Re: [time-nuts] FRK-L Rubidium
Bob, Just wanted to let you know your advice to let the FRK run for a while was spot on. The lock voltage is down to 9.2 volts. I was able to get my thunderbolt with the bad oscillator oven working by heating the oscillator with a power resistor. After it locked I could see on an oscilloscope that it and the FRK were both exactly the same. I plan on putting the thunderbolt oscillator in an oven I'm building that will have proportional control and see how that works. Thanks for the help. Garren -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Camp Sent: Saturday, February 09, 2013 10:14 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] FRK-L Rubidium Hi Let it run for a couple of days. If it's still up at > 11V, I'd tweak it down a bit. Bob On Feb 9, 2013, at 12:38 PM, Garren Davis wrote: > Found my problem with the FRK. R31 on the Osc board was burned and open. This > was caused by a shorted C16. Replaced and it is now locked. The lock voltage > is 12.7v. Is this good or should it be lower? > > Garren > > > > > On Feb 9, 2013, at 6:10 AM, "Bob Camp" wrote: > >> Hi >> >> How old is the FRK? Does it look like it's been run without a heat sink for >> very long? They tend to get flaky if run for a while (many months) without >> heat sinking. There's nothing mysterious about it. The MTBF of the parts >> gets noticeably worse as the unit heats up. >> >> Bob >> >> On Feb 9, 2013, at 1:09 AM, Garren Davis wrote: >> >>> >>> Well for some reason the 10 Mhz stopped working on the FRK. Don't know why. >>> Started up the thunderbolt. It acquired satellites but then the DAC voltage >>> went to -5 volts. It's been there for an hour. Will this change after the >>> unit stabilizes? Going to bed. Will check it tomorrow. >>> >>> Garren >>> >>> >>> >>> >>> On Feb 8, 2013, at 8:25 PM, "Ed Palmer" wrote: >>> >>>> Hi Garren, >>>> >>>> I suggest that you get the Thunderbolt working first. Without a known 10 >>>> MHz source to compare to, you're flying blind. Once the Tbolt is running, >>>> you should be able to check the frequency of the FRK by feeding both into >>>> your scope. Trigger on the Tbolt and watch what the FRK does. You should >>>> see the trace scrolling in one direction, then slow down, then stop, then >>>> scroll the other direction. The 'stop' point is at 10 MHz. The frequency >>>> sweeps a total of 20-30 Hz so it's easy to see. If you don't see the >>>> 'stop' point, the FRK isn't getting to 10 MHz. Now use the best frequency >>>> counter you've got to measure the Tbolt. Regardless of the calibration of >>>> your counter, the number your counter gives you becomes your 'new' 10 MHz. >>>> Now measure the FRK to see if it's running fast or slow. >>>> >>>> You should check the temperature of the lamp. It's easy to get at by >>>> removing the cover in the center of the heat sink. Probably best to >>>> remove the cover and then power down before you go poking around inside! >>>> The temperature of the cavity is also important, but getting to it is more >>>> of a hassle - don't go there if you don't have to. >>>> >>>> Of course, check for the normal things like internal power supply >>>> voltages, ripple, current drain (both initial and steady-state), etc. >>>> >>>> Regarding your second message, yes, the adjustment under the heat sink >>>> near the edge is the C-field. That won't help you at this point. The >>>> adjustment in the center of one side is the VCO. You could try adjusting >>>> it, but like I said, you're flying blind at this point. You won't know if >>>> you're adjusting closer to 10 MHz or further away. >>>> >>>> Good luck, >>>> >>>> Ed >>>> >>>> >>>> On 2/8/2013 6:12 PM, Garren Davis wrote: >>>>> Been lurking on the list for a while and finally started playing >>>>> with a FRK-L rubidium frequency standard. I've had this thing for >>>>> a while and decided to power it up and see what it would do. I do >>>>> not get a lock. What I see is the lamp voltage at 8.54 volts which >>>>> I
Re: [time-nuts] FRK-L Rubidium
It is possible to open the can if you are careful. A good vacuum desoldering tool is a good start to remove as much of the solder as possible. Then one would peal the can open a bit at a time. Then you need to find out where the failure is. But to answer your question, yes just buy one, it's much easier. But first check that there is power to the heater. - Original Message - From: "Garren Davis" To: "Discussion of precise time and frequency measurement" Sent: Monday, February 11, 2013 12:01 PM Subject: Re: [time-nuts] FRK-L Rubidium Ed, Bob, This morning I noticed the crystal control voltage was down to 11 volts. I'll let it keep running to see if it drops any further. The tuning capacitor is adjusted out about as far as I want to set it. Any further and I think the adjustment screw will fall out. I did remove C11 as an experiment to see what it would do to the frequency. It dropped a lot so now I know I can put a smaller one in if I need more adjustment. Next up is the Tbolt. I'm pretty sure the oven heater is not working. Has anyone taken apart the trimble oscillator? It looks like it's sealed pretty good. I see quite a few for sale. Is it just easier to replace it? Thanks for all the help. Garren -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Ed Palmer Sent: Sunday, February 10, 2013 11:02 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] FRK-L Rubidium Hi Garren, Yes, you're right. Silly me, I made the mistake of believing what was written in the manual which says 2-12 volts. When I measure it, I see ~2-16 volts. Let that be a warning to you. This isn't the first time that manual has led me astray! I should have known better. Did you notice that the voltage changes as you adjust the capacitor on the side? If the adjustment is at it's limit, you may have to change capacitors A3C11 and maybe A3C12 to get the oscillator back on frequency. It's explained in the manual. :-) Let it settle for at least a few days and see which direction the crystal control voltage moves. If it falls you're fine. If it rises higher, you may want to look at the capacitors. If you have to change the capacitors, be sure to use NP0/C0G type capacitors. Bob's comments regarding the C-field are right on the money. It's for fine tuning after you have a stable lock. It won't help you obtain or maintain a lock. You won't be able to adjust it without a known, stable 10 MHz reference source like the Tbolt and some good measurement equipment. Ed On 2/10/2013 9:27 AM, Garren Davis wrote: Hi Ed, The voltage swings from 2v to 17v. Doesn't that mean I have about 4 to 5 volt margin if it's locked at 12 volts? I had to adjust the capacitor out almost all the way to get it to lock. If I need to adjust it more can I use the C-field adjustment or should I stay away from that? Garren On Feb 9, 2013, at 10:48 PM, "Ed Palmer" wrote: Hi Garren, Congrats on your repair. Since the crystal control voltage is spec'd as ~1 to 12 Vdc, you're apparently holding onto lock by the narrowest of margins. You definitely want to adjust the oscillator to bring that voltage closer to the middle of it's range. Ed On 2/9/2013 11:38 AM, Garren Davis wrote: Found my problem with the FRK. R31 on the Osc board was burned and open. This was caused by a shorted C16. Replaced and it is now locked. The lock voltage is 12.7v. Is this good or should it be lower? Garren On Feb 9, 2013, at 6:10 AM, "Bob Camp" wrote: Hi How old is the FRK? Does it look like it's been run without a heat sink for very long? They tend to get flaky if run for a while (many months) without heat sinking. There's nothing mysterious about it. The MTBF of the parts gets noticeably worse as the unit heats up. Bob On Feb 9, 2013, at 1:09 AM, Garren Davis wrote: Well for some reason the 10 Mhz stopped working on the FRK. Don't know why. Started up the thunderbolt. It acquired satellites but then the DAC voltage went to -5 volts. It's been there for an hour. Will this change after the unit stabilizes? Going to bed. Will check it tomorrow. Garren On Feb 8, 2013, at 8:25 PM, "Ed Palmer" wrote: Hi Garren, I suggest that you get the Thunderbolt working first. Without a known 10 MHz source to compare to, you're flying blind. Once the Tbolt is running, you should be able to check the frequency of the FRK by feeding both into your scope. Trigger on the Tbolt and watch what the FRK does. You should see the trace scrolling in one direction, then slow down, then stop, then scroll the other direction. The 'stop' point is at 10 MHz. The frequency sweeps a total of 20-30 Hz so it's easy to see. If you don't
Re: [time-nuts] FRK-L Rubidium
Ed, Bob, This morning I noticed the crystal control voltage was down to 11 volts. I'll let it keep running to see if it drops any further. The tuning capacitor is adjusted out about as far as I want to set it. Any further and I think the adjustment screw will fall out. I did remove C11 as an experiment to see what it would do to the frequency. It dropped a lot so now I know I can put a smaller one in if I need more adjustment. Next up is the Tbolt. I'm pretty sure the oven heater is not working. Has anyone taken apart the trimble oscillator? It looks like it's sealed pretty good. I see quite a few for sale. Is it just easier to replace it? Thanks for all the help. Garren -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Ed Palmer Sent: Sunday, February 10, 2013 11:02 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] FRK-L Rubidium Hi Garren, Yes, you're right. Silly me, I made the mistake of believing what was written in the manual which says 2-12 volts. When I measure it, I see ~2-16 volts. Let that be a warning to you. This isn't the first time that manual has led me astray! I should have known better. Did you notice that the voltage changes as you adjust the capacitor on the side? If the adjustment is at it's limit, you may have to change capacitors A3C11 and maybe A3C12 to get the oscillator back on frequency. It's explained in the manual. :-) Let it settle for at least a few days and see which direction the crystal control voltage moves. If it falls you're fine. If it rises higher, you may want to look at the capacitors. If you have to change the capacitors, be sure to use NP0/C0G type capacitors. Bob's comments regarding the C-field are right on the money. It's for fine tuning after you have a stable lock. It won't help you obtain or maintain a lock. You won't be able to adjust it without a known, stable 10 MHz reference source like the Tbolt and some good measurement equipment. Ed On 2/10/2013 9:27 AM, Garren Davis wrote: > Hi Ed, > > The voltage swings from 2v to 17v. Doesn't that mean I have about 4 to 5 volt > margin if it's locked at 12 volts? > > I had to adjust the capacitor out almost all the way to get it to lock. If I > need to adjust it more can I use the C-field adjustment or should I stay away > from that? > > Garren > > > On Feb 9, 2013, at 10:48 PM, "Ed Palmer" wrote: > >> Hi Garren, >> >> Congrats on your repair. Since the crystal control voltage is spec'd as ~1 >> to 12 Vdc, you're apparently holding onto lock by the narrowest of margins. >> You definitely want to adjust the oscillator to bring that voltage closer to >> the middle of it's range. >> >> Ed >> >> On 2/9/2013 11:38 AM, Garren Davis wrote: >>> Found my problem with the FRK. R31 on the Osc board was burned and open. >>> This was caused by a shorted C16. Replaced and it is now locked. The lock >>> voltage is 12.7v. Is this good or should it be lower? >>> >>> Garren >>> >>> On Feb 9, 2013, at 6:10 AM, "Bob Camp" wrote: >>> >>>> Hi >>>> >>>> How old is the FRK? Does it look like it's been run without a heat sink >>>> for very long? They tend to get flaky if run for a while (many months) >>>> without heat sinking. There's nothing mysterious about it. The MTBF of the >>>> parts gets noticeably worse as the unit heats up. >>>> >>>> Bob >>>> >>>> On Feb 9, 2013, at 1:09 AM, Garren Davis wrote: >>>> >>>>> Well for some reason the 10 Mhz stopped working on the FRK. Don't know >>>>> why. Started up the thunderbolt. It acquired satellites but then the DAC >>>>> voltage went to -5 volts. It's been there for an hour. Will this change >>>>> after the unit stabilizes? Going to bed. Will check it tomorrow. >>>>> >>>>> Garren >>>>> >>>>> >>>>> On Feb 8, 2013, at 8:25 PM, "Ed Palmer" wrote: >>>>> >>>>>> Hi Garren, >>>>>> >>>>>> I suggest that you get the Thunderbolt working first. Without a known >>>>>> 10 MHz source to compare to, you're flying blind. Once the Tbolt is >>>>>> running, you should be able to check the frequency of the FRK by feeding >>>>>> both into your scope. Trigger on the Tbolt and watch what the FRK does. >>>>>> You should see the trace scrolling i
Re: [time-nuts] FRK-L Rubidium
Hi Garren, Yes, you're right. Silly me, I made the mistake of believing what was written in the manual which says 2-12 volts. When I measure it, I see ~2-16 volts. Let that be a warning to you. This isn't the first time that manual has led me astray! I should have known better. Did you notice that the voltage changes as you adjust the capacitor on the side? If the adjustment is at it's limit, you may have to change capacitors A3C11 and maybe A3C12 to get the oscillator back on frequency. It's explained in the manual. :-) Let it settle for at least a few days and see which direction the crystal control voltage moves. If it falls you're fine. If it rises higher, you may want to look at the capacitors. If you have to change the capacitors, be sure to use NP0/C0G type capacitors. Bob's comments regarding the C-field are right on the money. It's for fine tuning after you have a stable lock. It won't help you obtain or maintain a lock. You won't be able to adjust it without a known, stable 10 MHz reference source like the Tbolt and some good measurement equipment. Ed On 2/10/2013 9:27 AM, Garren Davis wrote: Hi Ed, The voltage swings from 2v to 17v. Doesn't that mean I have about 4 to 5 volt margin if it's locked at 12 volts? I had to adjust the capacitor out almost all the way to get it to lock. If I need to adjust it more can I use the C-field adjustment or should I stay away from that? Garren On Feb 9, 2013, at 10:48 PM, "Ed Palmer" wrote: Hi Garren, Congrats on your repair. Since the crystal control voltage is spec'd as ~1 to 12 Vdc, you're apparently holding onto lock by the narrowest of margins. You definitely want to adjust the oscillator to bring that voltage closer to the middle of it's range. Ed On 2/9/2013 11:38 AM, Garren Davis wrote: Found my problem with the FRK. R31 on the Osc board was burned and open. This was caused by a shorted C16. Replaced and it is now locked. The lock voltage is 12.7v. Is this good or should it be lower? Garren On Feb 9, 2013, at 6:10 AM, "Bob Camp" wrote: Hi How old is the FRK? Does it look like it's been run without a heat sink for very long? They tend to get flaky if run for a while (many months) without heat sinking. There's nothing mysterious about it. The MTBF of the parts gets noticeably worse as the unit heats up. Bob On Feb 9, 2013, at 1:09 AM, Garren Davis wrote: Well for some reason the 10 Mhz stopped working on the FRK. Don't know why. Started up the thunderbolt. It acquired satellites but then the DAC voltage went to -5 volts. It's been there for an hour. Will this change after the unit stabilizes? Going to bed. Will check it tomorrow. Garren On Feb 8, 2013, at 8:25 PM, "Ed Palmer" wrote: Hi Garren, I suggest that you get the Thunderbolt working first. Without a known 10 MHz source to compare to, you're flying blind. Once the Tbolt is running, you should be able to check the frequency of the FRK by feeding both into your scope. Trigger on the Tbolt and watch what the FRK does. You should see the trace scrolling in one direction, then slow down, then stop, then scroll the other direction. The 'stop' point is at 10 MHz. The frequency sweeps a total of 20-30 Hz so it's easy to see. If you don't see the 'stop' point, the FRK isn't getting to 10 MHz. Now use the best frequency counter you've got to measure the Tbolt. Regardless of the calibration of your counter, the number your counter gives you becomes your 'new' 10 MHz. Now measure the FRK to see if it's running fast or slow. You should check the temperature of the lamp. It's easy to get at by removing the cover in the center of the heat sink. Probably best to remove the cover and then power down before you go poking around inside! The temperature of the cavity is also important, but getting to it is more of a hassle - don't go there if you don't have to. Of course, check for the normal things like internal power supply voltages, ripple, current drain (both initial and steady-state), etc. Regarding your second message, yes, the adjustment under the heat sink near the edge is the C-field. That won't help you at this point. The adjustment in the center of one side is the VCO. You could try adjusting it, but like I said, you're flying blind at this point. You won't know if you're adjusting closer to 10 MHz or further away. Good luck, Ed On 2/8/2013 6:12 PM, Garren Davis wrote: Been lurking on the list for a while and finally started playing with a FRK-L rubidium frequency standard. I've had this thing for a while and decided to power it up and see what it would do. I do not get a lock. What I see is the lamp voltage at 8.54 volts which I think is good but the xtal control voltage swings from 2 volts to 15 volts and back to 2 volts and keeps cycling like that. I don't have a good frequency counter but I have a 3 Ghz 40 G/sample scope and it shows that the 10 MHz signal is there. I jus
Re: [time-nuts] FRK-L Rubidium
Hi The OCVCXO tuning voltage adjust on the 10 MHz simply centers up the sweep process. It has no impact on the output frequency once the unit is locked up. The C field adjustment sets the Rb on frequency once it is locked. It is only used to set the unit on frequency. Since the range on the C field is maybe 0.002 ppm and the 10 MHz set is maybe 1 ppm, there is little the C field would do to "help" the 10 MHz adjust. It is quite possible for the crystal in the 10 MHz oscillator to age further than tuning range on the oscillator. You can either replace the crystal (good luck) or fiddle one of the fixed caps in the oscillator circuit (normally much easier). Bob On Feb 10, 2013, at 10:27 AM, Garren Davis wrote: > > Hi Ed, > > The voltage swings from 2v to 17v. Doesn't that mean I have about 4 to 5 volt > margin if it's locked at 12 volts? > > I had to adjust the capacitor out almost all the way to get it to lock. If I > need to adjust it more can I use the C-field adjustment or should I stay away > from that? > > Garren > > > > > On Feb 9, 2013, at 10:48 PM, "Ed Palmer" wrote: > >> Hi Garren, >> >> Congrats on your repair. Since the crystal control voltage is spec'd as ~1 >> to 12 Vdc, you're apparently holding onto lock by the narrowest of margins. >> You definitely want to adjust the oscillator to bring that voltage closer to >> the middle of it's range. >> >> Ed >> >> On 2/9/2013 11:38 AM, Garren Davis wrote: >>> Found my problem with the FRK. R31 on the Osc board was burned and open. >>> This was caused by a shorted C16. Replaced and it is now locked. The lock >>> voltage is 12.7v. Is this good or should it be lower? >>> >>> Garren >>> >>> On Feb 9, 2013, at 6:10 AM, "Bob Camp" wrote: >>> Hi How old is the FRK? Does it look like it's been run without a heat sink for very long? They tend to get flaky if run for a while (many months) without heat sinking. There's nothing mysterious about it. The MTBF of the parts gets noticeably worse as the unit heats up. Bob On Feb 9, 2013, at 1:09 AM, Garren Davis wrote: > Well for some reason the 10 Mhz stopped working on the FRK. Don't know > why. Started up the thunderbolt. It acquired satellites but then the DAC > voltage went to -5 volts. It's been there for an hour. Will this change > after the unit stabilizes? Going to bed. Will check it tomorrow. > > Garren > > > On Feb 8, 2013, at 8:25 PM, "Ed Palmer" wrote: > >> Hi Garren, >> >> I suggest that you get the Thunderbolt working first. Without a known >> 10 MHz source to compare to, you're flying blind. Once the Tbolt is >> running, you should be able to check the frequency of the FRK by feeding >> both into your scope. Trigger on the Tbolt and watch what the FRK does. >> You should see the trace scrolling in one direction, then slow down, >> then stop, then scroll the other direction. The 'stop' point is at 10 >> MHz. The frequency sweeps a total of 20-30 Hz so it's easy to see. If >> you don't see the 'stop' point, the FRK isn't getting to 10 MHz. Now >> use the best frequency counter you've got to measure the Tbolt. >> Regardless of the calibration of your counter, the number your counter >> gives you becomes your 'new' 10 MHz. Now measure the FRK to see if it's >> running fast or slow. >> >> You should check the temperature of the lamp. It's easy to get at by >> removing the cover in the center of the heat sink. Probably best to >> remove the cover and then power down before you go poking around inside! >> The temperature of the cavity is also important, but getting to it is >> more of a hassle - don't go there if you don't have to. >> >> Of course, check for the normal things like internal power supply >> voltages, ripple, current drain (both initial and steady-state), etc. >> >> Regarding your second message, yes, the adjustment under the heat sink >> near the edge is the C-field. That won't help you at this point. The >> adjustment in the center of one side is the VCO. You could try >> adjusting it, but like I said, you're flying blind at this point. You >> won't know if you're adjusting closer to 10 MHz or further away. >> >> Good luck, >> >> Ed >> >> >> On 2/8/2013 6:12 PM, Garren Davis wrote: >>> Been lurking on the list for a while and finally started playing with a >>> FRK-L rubidium frequency standard. I've had this thing for a while and >>> decided to power it up and see what it would do. I do not get a lock. >>> What I see is the lamp voltage at 8.54 volts which I think is good but >>> the xtal control voltage swings from 2 volts to 15 volts and back to 2 >>> volts and keeps cycling like that. I don't have a good frequency >>>
Re: [time-nuts] FRK-L Rubidium
Bob, That was my thoughts also. The GPS receiver and serial connection to the computer are working so I know the power connections are ok. I think I bought this through a group buy from someone on this list and they said all were tested before they were shipped. Maybe it was just time for the heater to fail. Are these trimbles repairable or is it easier to just replace these? Garren On Feb 9, 2013, at 8:14 AM, "Bob Camp" wrote: > Hi > > The +12 V supply at 60 ma likely means that the heater in the OCXO is not > working. If you have 60 ma on the -12 V supply, it's pulling about 10X more > than it should. > > Bob > > On Feb 9, 2013, at 10:01 AM, Garren Davis wrote: > >> Thanks for the reply. >> I found that the 12v current is only 60ma. I suppose that means the Osc. >> heater is not working. I'm not having much luck with this time nuts stuff. >> First the FRK and now the thunderbolt. Guess I'll start looking for another >> one. >> >> Garren >> >> >> >> >> On Feb 9, 2013, at 6:01 AM, "Bob Camp" wrote: >> >>> Hi >>> >>> DAC clamped at -5 volts suggests that the TBolt has issues. First thing to >>> check is the -12 volt supply. If it's missing, the DAC will indicate -5 on >>> the screen and be sitting at 0 in real life. There are a couple other >>> things in the DAC circuit that can make it malfunction. >>> >>> Bob >>> >>> On Feb 9, 2013, at 1:09 AM, Garren Davis wrote: >>> Well for some reason the 10 Mhz stopped working on the FRK. Don't know why. Started up the thunderbolt. It acquired satellites but then the DAC voltage went to -5 volts. It's been there for an hour. Will this change after the unit stabilizes? Going to bed. Will check it tomorrow. Garren On Feb 8, 2013, at 8:25 PM, "Ed Palmer" wrote: > Hi Garren, > > I suggest that you get the Thunderbolt working first. Without a known 10 > MHz source to compare to, you're flying blind. Once the Tbolt is > running, you should be able to check the frequency of the FRK by feeding > both into your scope. Trigger on the Tbolt and watch what the FRK does. > You should see the trace scrolling in one direction, then slow down, then > stop, then scroll the other direction. The 'stop' point is at 10 MHz. > The frequency sweeps a total of 20-30 Hz so it's easy to see. If you > don't see the 'stop' point, the FRK isn't getting to 10 MHz. Now use the > best frequency counter you've got to measure the Tbolt. Regardless of > the calibration of your counter, the number your counter gives you > becomes your 'new' 10 MHz. Now measure the FRK to see if it's running > fast or slow. > > You should check the temperature of the lamp. It's easy to get at by > removing the cover in the center of the heat sink. Probably best to > remove the cover and then power down before you go poking around inside! > The temperature of the cavity is also important, but getting to it is > more of a hassle - don't go there if you don't have to. > > Of course, check for the normal things like internal power supply > voltages, ripple, current drain (both initial and steady-state), etc. > > Regarding your second message, yes, the adjustment under the heat sink > near the edge is the C-field. That won't help you at this point. The > adjustment in the center of one side is the VCO. You could try adjusting > it, but like I said, you're flying blind at this point. You won't know > if you're adjusting closer to 10 MHz or further away. > > Good luck, > > Ed > > > On 2/8/2013 6:12 PM, Garren Davis wrote: >> Been lurking on the list for a while and finally started playing with a >> FRK-L rubidium frequency standard. I've had this thing for a while and >> decided to power it up and see what it would do. I do not get a lock. >> What I see is the lamp voltage at 8.54 volts which I think is good but >> the xtal control voltage swings from 2 volts to 15 volts and back to 2 >> volts and keeps cycling like that. I don't have a good frequency counter >> but I have a 3 Ghz 40 G/sample scope and it shows that the 10 MHz signal >> is there. I just don't know how accurate it is. Has anyone seen a >> problem like this? Can anyone point me to a place to start debugging >> this? I have the schematics and test tools. I am a test engineer so I'm >> not afraid to poke around in the guts of this thing. Hopefully I can get >> this thing running. I also have a thunderbolt that I'll get running this >> weekend. I don't know how deep I'll get into this time-nuts thing but I >> have this nice scope and a Wavecrest sitting in my garage > >> a >>> n d > I'd lik > e to put them to use. Any help would be appreciated. >> >> Garren > > __
Re: [time-nuts] FRK-L Rubidium
Hi Ed, The voltage swings from 2v to 17v. Doesn't that mean I have about 4 to 5 volt margin if it's locked at 12 volts? I had to adjust the capacitor out almost all the way to get it to lock. If I need to adjust it more can I use the C-field adjustment or should I stay away from that? Garren On Feb 9, 2013, at 10:48 PM, "Ed Palmer" wrote: > Hi Garren, > > Congrats on your repair. Since the crystal control voltage is spec'd as ~1 > to 12 Vdc, you're apparently holding onto lock by the narrowest of margins. > You definitely want to adjust the oscillator to bring that voltage closer to > the middle of it's range. > > Ed > > On 2/9/2013 11:38 AM, Garren Davis wrote: >> Found my problem with the FRK. R31 on the Osc board was burned and open. >> This was caused by a shorted C16. Replaced and it is now locked. The lock >> voltage is 12.7v. Is this good or should it be lower? >> >> Garren >> >> On Feb 9, 2013, at 6:10 AM, "Bob Camp" wrote: >> >>> Hi >>> >>> How old is the FRK? Does it look like it's been run without a heat sink for >>> very long? They tend to get flaky if run for a while (many months) without >>> heat sinking. There's nothing mysterious about it. The MTBF of the parts >>> gets noticeably worse as the unit heats up. >>> >>> Bob >>> >>> On Feb 9, 2013, at 1:09 AM, Garren Davis wrote: >>> Well for some reason the 10 Mhz stopped working on the FRK. Don't know why. Started up the thunderbolt. It acquired satellites but then the DAC voltage went to -5 volts. It's been there for an hour. Will this change after the unit stabilizes? Going to bed. Will check it tomorrow. Garren On Feb 8, 2013, at 8:25 PM, "Ed Palmer" wrote: > Hi Garren, > > I suggest that you get the Thunderbolt working first. Without a known 10 > MHz source to compare to, you're flying blind. Once the Tbolt is > running, you should be able to check the frequency of the FRK by feeding > both into your scope. Trigger on the Tbolt and watch what the FRK does. > You should see the trace scrolling in one direction, then slow down, then > stop, then scroll the other direction. The 'stop' point is at 10 MHz. > The frequency sweeps a total of 20-30 Hz so it's easy to see. If you > don't see the 'stop' point, the FRK isn't getting to 10 MHz. Now use the > best frequency counter you've got to measure the Tbolt. Regardless of > the calibration of your counter, the number your counter gives you > becomes your 'new' 10 MHz. Now measure the FRK to see if it's running > fast or slow. > > You should check the temperature of the lamp. It's easy to get at by > removing the cover in the center of the heat sink. Probably best to > remove the cover and then power down before you go poking around inside! > The temperature of the cavity is also important, but getting to it is > more of a hassle - don't go there if you don't have to. > > Of course, check for the normal things like internal power supply > voltages, ripple, current drain (both initial and steady-state), etc. > > Regarding your second message, yes, the adjustment under the heat sink > near the edge is the C-field. That won't help you at this point. The > adjustment in the center of one side is the VCO. You could try adjusting > it, but like I said, you're flying blind at this point. You won't know > if you're adjusting closer to 10 MHz or further away. > > Good luck, > > Ed > > > On 2/8/2013 6:12 PM, Garren Davis wrote: >> Been lurking on the list for a while and finally started playing with a >> FRK-L rubidium frequency standard. I've had this thing for a while and >> decided to power it up and see what it would do. I do not get a lock. >> What I see is the lamp voltage at 8.54 volts which I think is good but >> the xtal control voltage swings from 2 volts to 15 volts and back to 2 >> volts and keeps cycling like that. I don't have a good frequency counter >> but I have a 3 Ghz 40 G/sample scope and it shows that the 10 MHz signal >> is there. I just don't know how accurate it is. Has anyone seen a >> problem like this? Can anyone point me to a place to start debugging >> this? I have the schematics and test tools. I am a test engineer so I'm >> not afraid to poke around in the guts of this thing. Hopefully I can get >> this thing running. I also have a thunderbolt that I'll get running this >> weekend. I don't know how deep I'll get into this time-nuts thing but I >> have this nice scope and a Wavecrest sitting in my garage > and I'd > like to put them to use. Any help would be appreciated. >> Garren > > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listin
Re: [time-nuts] FRK-L Rubidium
Hi Garren, Congrats on your repair. Since the crystal control voltage is spec'd as ~1 to 12 Vdc, you're apparently holding onto lock by the narrowest of margins. You definitely want to adjust the oscillator to bring that voltage closer to the middle of it's range. Ed On 2/9/2013 11:38 AM, Garren Davis wrote: Found my problem with the FRK. R31 on the Osc board was burned and open. This was caused by a shorted C16. Replaced and it is now locked. The lock voltage is 12.7v. Is this good or should it be lower? Garren On Feb 9, 2013, at 6:10 AM, "Bob Camp" wrote: Hi How old is the FRK? Does it look like it's been run without a heat sink for very long? They tend to get flaky if run for a while (many months) without heat sinking. There's nothing mysterious about it. The MTBF of the parts gets noticeably worse as the unit heats up. Bob On Feb 9, 2013, at 1:09 AM, Garren Davis wrote: Well for some reason the 10 Mhz stopped working on the FRK. Don't know why. Started up the thunderbolt. It acquired satellites but then the DAC voltage went to -5 volts. It's been there for an hour. Will this change after the unit stabilizes? Going to bed. Will check it tomorrow. Garren On Feb 8, 2013, at 8:25 PM, "Ed Palmer" wrote: Hi Garren, I suggest that you get the Thunderbolt working first. Without a known 10 MHz source to compare to, you're flying blind. Once the Tbolt is running, you should be able to check the frequency of the FRK by feeding both into your scope. Trigger on the Tbolt and watch what the FRK does. You should see the trace scrolling in one direction, then slow down, then stop, then scroll the other direction. The 'stop' point is at 10 MHz. The frequency sweeps a total of 20-30 Hz so it's easy to see. If you don't see the 'stop' point, the FRK isn't getting to 10 MHz. Now use the best frequency counter you've got to measure the Tbolt. Regardless of the calibration of your counter, the number your counter gives you becomes your 'new' 10 MHz. Now measure the FRK to see if it's running fast or slow. You should check the temperature of the lamp. It's easy to get at by removing the cover in the center of the heat sink. Probably best to remove the cover and then power down before you go poking around inside! The temperature of the cavity is also important, but getting to it is more of a hassle - don't go there if you don't have to. Of course, check for the normal things like internal power supply voltages, ripple, current drain (both initial and steady-state), etc. Regarding your second message, yes, the adjustment under the heat sink near the edge is the C-field. That won't help you at this point. The adjustment in the center of one side is the VCO. You could try adjusting it, but like I said, you're flying blind at this point. You won't know if you're adjusting closer to 10 MHz or further away. Good luck, Ed On 2/8/2013 6:12 PM, Garren Davis wrote: Been lurking on the list for a while and finally started playing with a FRK-L rubidium frequency standard. I've had this thing for a while and decided to power it up and see what it would do. I do not get a lock. What I see is the lamp voltage at 8.54 volts which I think is good but the xtal control voltage swings from 2 volts to 15 volts and back to 2 volts and keeps cycling like that. I don't have a good frequency counter but I have a 3 Ghz 40 G/sample scope and it shows that the 10 MHz signal is there. I just don't know how accurate it is. Has anyone seen a problem like this? Can anyone point me to a place to start debugging this? I have the schematics and test tools. I am a test engineer so I'm not afraid to poke around in the guts of this thing. Hopefully I can get this thing running. I also have a thunderbolt that I'll get running this weekend. I don't know how deep I'll get into this time-nuts thing but I have this nice scope and a Wavecrest sitting in my garage and I'd like to put them to use. Any help would be appreciated. Garren ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] FRK-L Rubidium
I'll add my own FRK-L failure story. I have a FRK that suddenly stopped locking. The 10 MHz was there, but off frequency so much that I couldn't adjust it to sweep over 10 MHz. It suddenly occurred to me that the crystal oven housing should be hotter than just barely warm to the touch (it's usually too hot to touch). I found that the Darlington transistor that is used as a oven heater was bad. Replacing the transistor fixed the problem. Tom --- On Sat, 2/9/13, Dan Rae wrote: From: Dan Rae Subject: Re: [time-nuts] FRK-L Rubidium To: "Discussion of precise time and frequency measurement" Date: Saturday, February 9, 2013, 10:31 AM Since we're offering up faults for the FRK, I'll add one that I've found: there's a CMOS 4060 oscillator that should go off at 8.128 kHz, set by an adjust on test R. If this drifts off enough the lock will never happen. It provides the FM frequency for the synth. Dan ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] FRK-L Rubidium
Since we're offering up faults for the FRK, I'll add one that I've found: there's a CMOS 4060 oscillator that should go off at 8.128 kHz, set by an adjust on test R. If this drifts off enough the lock will never happen. It provides the FM frequency for the synth. Dan ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] FRK-L Rubidium
Hi Let it run for a couple of days. If it's still up at > 11V, I'd tweak it down a bit. Bob On Feb 9, 2013, at 12:38 PM, Garren Davis wrote: > Found my problem with the FRK. R31 on the Osc board was burned and open. This > was caused by a shorted C16. Replaced and it is now locked. The lock voltage > is 12.7v. Is this good or should it be lower? > > Garren > > > > > On Feb 9, 2013, at 6:10 AM, "Bob Camp" wrote: > >> Hi >> >> How old is the FRK? Does it look like it's been run without a heat sink for >> very long? They tend to get flaky if run for a while (many months) without >> heat sinking. There's nothing mysterious about it. The MTBF of the parts >> gets noticeably worse as the unit heats up. >> >> Bob >> >> On Feb 9, 2013, at 1:09 AM, Garren Davis wrote: >> >>> >>> Well for some reason the 10 Mhz stopped working on the FRK. Don't know why. >>> Started up the thunderbolt. It acquired satellites but then the DAC voltage >>> went to -5 volts. It's been there for an hour. Will this change after the >>> unit stabilizes? Going to bed. Will check it tomorrow. >>> >>> Garren >>> >>> >>> >>> >>> On Feb 8, 2013, at 8:25 PM, "Ed Palmer" wrote: >>> Hi Garren, I suggest that you get the Thunderbolt working first. Without a known 10 MHz source to compare to, you're flying blind. Once the Tbolt is running, you should be able to check the frequency of the FRK by feeding both into your scope. Trigger on the Tbolt and watch what the FRK does. You should see the trace scrolling in one direction, then slow down, then stop, then scroll the other direction. The 'stop' point is at 10 MHz. The frequency sweeps a total of 20-30 Hz so it's easy to see. If you don't see the 'stop' point, the FRK isn't getting to 10 MHz. Now use the best frequency counter you've got to measure the Tbolt. Regardless of the calibration of your counter, the number your counter gives you becomes your 'new' 10 MHz. Now measure the FRK to see if it's running fast or slow. You should check the temperature of the lamp. It's easy to get at by removing the cover in the center of the heat sink. Probably best to remove the cover and then power down before you go poking around inside! The temperature of the cavity is also important, but getting to it is more of a hassle - don't go there if you don't have to. Of course, check for the normal things like internal power supply voltages, ripple, current drain (both initial and steady-state), etc. Regarding your second message, yes, the adjustment under the heat sink near the edge is the C-field. That won't help you at this point. The adjustment in the center of one side is the VCO. You could try adjusting it, but like I said, you're flying blind at this point. You won't know if you're adjusting closer to 10 MHz or further away. Good luck, Ed On 2/8/2013 6:12 PM, Garren Davis wrote: > Been lurking on the list for a while and finally started playing with a > FRK-L rubidium frequency standard. I've had this thing for a while and > decided to power it up and see what it would do. I do not get a lock. > What I see is the lamp voltage at 8.54 volts which I think is good but > the xtal control voltage swings from 2 volts to 15 volts and back to 2 > volts and keeps cycling like that. I don't have a good frequency counter > but I have a 3 Ghz 40 G/sample scope and it shows that the 10 MHz signal > is there. I just don't know how accurate it is. Has anyone seen a problem > like this? Can anyone point me to a place to start debugging this? I have > the schematics and test tools. I am a test engineer so I'm not afraid to > poke around in the guts of this thing. Hopefully I can get this thing > running. I also have a thunderbolt that I'll get running this weekend. I > don't know how deep I'll get into this time-nuts thing but I have this > nice scope and a Wavecrest sitting in my garage > a >> n >>> d I'd lik e to put them to use. Any help would be appreciated. > > Garren ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. >>> >>> >>> >>> This message and any attached documents contain information from QLogic >>> Corporation or its wholly-owned subsidiaries that may be confidential. If >>> you are not the intended recipient, you may not read, copy, distribute, or >>> use this information. If you have received this transmission in error, >>> please notify the sender immediately by reply e-mail and then delete this >>> message. >>> >>> __
Re: [time-nuts] FRK-L Rubidium
Found my problem with the FRK. R31 on the Osc board was burned and open. This was caused by a shorted C16. Replaced and it is now locked. The lock voltage is 12.7v. Is this good or should it be lower? Garren On Feb 9, 2013, at 6:10 AM, "Bob Camp" wrote: > Hi > > How old is the FRK? Does it look like it's been run without a heat sink for > very long? They tend to get flaky if run for a while (many months) without > heat sinking. There's nothing mysterious about it. The MTBF of the parts gets > noticeably worse as the unit heats up. > > Bob > > On Feb 9, 2013, at 1:09 AM, Garren Davis wrote: > >> >> Well for some reason the 10 Mhz stopped working on the FRK. Don't know why. >> Started up the thunderbolt. It acquired satellites but then the DAC voltage >> went to -5 volts. It's been there for an hour. Will this change after the >> unit stabilizes? Going to bed. Will check it tomorrow. >> >> Garren >> >> >> >> >> On Feb 8, 2013, at 8:25 PM, "Ed Palmer" wrote: >> >>> Hi Garren, >>> >>> I suggest that you get the Thunderbolt working first. Without a known 10 >>> MHz source to compare to, you're flying blind. Once the Tbolt is running, >>> you should be able to check the frequency of the FRK by feeding both into >>> your scope. Trigger on the Tbolt and watch what the FRK does. You should >>> see the trace scrolling in one direction, then slow down, then stop, then >>> scroll the other direction. The 'stop' point is at 10 MHz. The frequency >>> sweeps a total of 20-30 Hz so it's easy to see. If you don't see the >>> 'stop' point, the FRK isn't getting to 10 MHz. Now use the best frequency >>> counter you've got to measure the Tbolt. Regardless of the calibration of >>> your counter, the number your counter gives you becomes your 'new' 10 MHz. >>> Now measure the FRK to see if it's running fast or slow. >>> >>> You should check the temperature of the lamp. It's easy to get at by >>> removing the cover in the center of the heat sink. Probably best to remove >>> the cover and then power down before you go poking around inside! The >>> temperature of the cavity is also important, but getting to it is more of a >>> hassle - don't go there if you don't have to. >>> >>> Of course, check for the normal things like internal power supply voltages, >>> ripple, current drain (both initial and steady-state), etc. >>> >>> Regarding your second message, yes, the adjustment under the heat sink near >>> the edge is the C-field. That won't help you at this point. The >>> adjustment in the center of one side is the VCO. You could try adjusting >>> it, but like I said, you're flying blind at this point. You won't know if >>> you're adjusting closer to 10 MHz or further away. >>> >>> Good luck, >>> >>> Ed >>> >>> >>> On 2/8/2013 6:12 PM, Garren Davis wrote: Been lurking on the list for a while and finally started playing with a FRK-L rubidium frequency standard. I've had this thing for a while and decided to power it up and see what it would do. I do not get a lock. What I see is the lamp voltage at 8.54 volts which I think is good but the xtal control voltage swings from 2 volts to 15 volts and back to 2 volts and keeps cycling like that. I don't have a good frequency counter but I have a 3 Ghz 40 G/sample scope and it shows that the 10 MHz signal is there. I just don't know how accurate it is. Has anyone seen a problem like this? Can anyone point me to a place to start debugging this? I have the schematics and test tools. I am a test engineer so I'm not afraid to poke around in the guts of this thing. Hopefully I can get this thing running. I also have a thunderbolt that I'll get running this weekend. I don't know how deep I'll get into this time-nuts thing but I have this nice scope and a Wavecrest sitting in my garage a > n >> d >>> I'd lik >>> e to put them to use. Any help would be appreciated. Garren >>> >>> ___ >>> time-nuts mailing list -- time-nuts@febo.com >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >> >> >> >> This message and any attached documents contain information from QLogic >> Corporation or its wholly-owned subsidiaries that may be confidential. If >> you are not the intended recipient, you may not read, copy, distribute, or >> use this information. If you have received this transmission in error, >> please notify the sender immediately by reply e-mail and then delete this >> message. >> >> ___ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > > ___ > time-nuts mailing list -- time-nuts@febo.com > To un
Re: [time-nuts] FRK-L Rubidium
Hi The +12 V supply at 60 ma likely means that the heater in the OCXO is not working. If you have 60 ma on the -12 V supply, it's pulling about 10X more than it should. Bob On Feb 9, 2013, at 10:01 AM, Garren Davis wrote: > Thanks for the reply. > I found that the 12v current is only 60ma. I suppose that means the Osc. > heater is not working. I'm not having much luck with this time nuts stuff. > First the FRK and now the thunderbolt. Guess I'll start looking for another > one. > > Garren > > > > > On Feb 9, 2013, at 6:01 AM, "Bob Camp" wrote: > >> Hi >> >> DAC clamped at -5 volts suggests that the TBolt has issues. First thing to >> check is the -12 volt supply. If it's missing, the DAC will indicate -5 on >> the screen and be sitting at 0 in real life. There are a couple other things >> in the DAC circuit that can make it malfunction. >> >> Bob >> >> On Feb 9, 2013, at 1:09 AM, Garren Davis wrote: >> >>> >>> Well for some reason the 10 Mhz stopped working on the FRK. Don't know why. >>> Started up the thunderbolt. It acquired satellites but then the DAC voltage >>> went to -5 volts. It's been there for an hour. Will this change after the >>> unit stabilizes? Going to bed. Will check it tomorrow. >>> >>> Garren >>> >>> >>> >>> >>> On Feb 8, 2013, at 8:25 PM, "Ed Palmer" wrote: >>> Hi Garren, I suggest that you get the Thunderbolt working first. Without a known 10 MHz source to compare to, you're flying blind. Once the Tbolt is running, you should be able to check the frequency of the FRK by feeding both into your scope. Trigger on the Tbolt and watch what the FRK does. You should see the trace scrolling in one direction, then slow down, then stop, then scroll the other direction. The 'stop' point is at 10 MHz. The frequency sweeps a total of 20-30 Hz so it's easy to see. If you don't see the 'stop' point, the FRK isn't getting to 10 MHz. Now use the best frequency counter you've got to measure the Tbolt. Regardless of the calibration of your counter, the number your counter gives you becomes your 'new' 10 MHz. Now measure the FRK to see if it's running fast or slow. You should check the temperature of the lamp. It's easy to get at by removing the cover in the center of the heat sink. Probably best to remove the cover and then power down before you go poking around inside! The temperature of the cavity is also important, but getting to it is more of a hassle - don't go there if you don't have to. Of course, check for the normal things like internal power supply voltages, ripple, current drain (both initial and steady-state), etc. Regarding your second message, yes, the adjustment under the heat sink near the edge is the C-field. That won't help you at this point. The adjustment in the center of one side is the VCO. You could try adjusting it, but like I said, you're flying blind at this point. You won't know if you're adjusting closer to 10 MHz or further away. Good luck, Ed On 2/8/2013 6:12 PM, Garren Davis wrote: > Been lurking on the list for a while and finally started playing with a > FRK-L rubidium frequency standard. I've had this thing for a while and > decided to power it up and see what it would do. I do not get a lock. > What I see is the lamp voltage at 8.54 volts which I think is good but > the xtal control voltage swings from 2 volts to 15 volts and back to 2 > volts and keeps cycling like that. I don't have a good frequency counter > but I have a 3 Ghz 40 G/sample scope and it shows that the 10 MHz signal > is there. I just don't know how accurate it is. Has anyone seen a problem > like this? Can anyone point me to a place to start debugging this? I have > the schematics and test tools. I am a test engineer so I'm not afraid to > poke around in the guts of this thing. Hopefully I can get this thing > running. I also have a thunderbolt that I'll get running this weekend. I > don't know how deep I'll get into this time-nuts thing but I have this > nice scope and a Wavecrest sitting in my garage > a >> n >>> d I'd lik e to put them to use. Any help would be appreciated. > > Garren ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. >>> >>> >>> >>> This message and any attached documents contain information from QLogic >>> Corporation or its wholly-owned subsidiaries that may be confidential. If >>> you are not the intended recipient, you may not read, copy, distribute, or >>> use this information. If you have received this transm
Re: [time-nuts] FRK-L Rubidium
Thanks for the reply. I found that the 12v current is only 60ma. I suppose that means the Osc. heater is not working. I'm not having much luck with this time nuts stuff. First the FRK and now the thunderbolt. Guess I'll start looking for another one. Garren On Feb 9, 2013, at 6:01 AM, "Bob Camp" wrote: > Hi > > DAC clamped at -5 volts suggests that the TBolt has issues. First thing to > check is the -12 volt supply. If it's missing, the DAC will indicate -5 on > the screen and be sitting at 0 in real life. There are a couple other things > in the DAC circuit that can make it malfunction. > > Bob > > On Feb 9, 2013, at 1:09 AM, Garren Davis wrote: > >> >> Well for some reason the 10 Mhz stopped working on the FRK. Don't know why. >> Started up the thunderbolt. It acquired satellites but then the DAC voltage >> went to -5 volts. It's been there for an hour. Will this change after the >> unit stabilizes? Going to bed. Will check it tomorrow. >> >> Garren >> >> >> >> >> On Feb 8, 2013, at 8:25 PM, "Ed Palmer" wrote: >> >>> Hi Garren, >>> >>> I suggest that you get the Thunderbolt working first. Without a known 10 >>> MHz source to compare to, you're flying blind. Once the Tbolt is running, >>> you should be able to check the frequency of the FRK by feeding both into >>> your scope. Trigger on the Tbolt and watch what the FRK does. You should >>> see the trace scrolling in one direction, then slow down, then stop, then >>> scroll the other direction. The 'stop' point is at 10 MHz. The frequency >>> sweeps a total of 20-30 Hz so it's easy to see. If you don't see the >>> 'stop' point, the FRK isn't getting to 10 MHz. Now use the best frequency >>> counter you've got to measure the Tbolt. Regardless of the calibration of >>> your counter, the number your counter gives you becomes your 'new' 10 MHz. >>> Now measure the FRK to see if it's running fast or slow. >>> >>> You should check the temperature of the lamp. It's easy to get at by >>> removing the cover in the center of the heat sink. Probably best to remove >>> the cover and then power down before you go poking around inside! The >>> temperature of the cavity is also important, but getting to it is more of a >>> hassle - don't go there if you don't have to. >>> >>> Of course, check for the normal things like internal power supply voltages, >>> ripple, current drain (both initial and steady-state), etc. >>> >>> Regarding your second message, yes, the adjustment under the heat sink near >>> the edge is the C-field. That won't help you at this point. The >>> adjustment in the center of one side is the VCO. You could try adjusting >>> it, but like I said, you're flying blind at this point. You won't know if >>> you're adjusting closer to 10 MHz or further away. >>> >>> Good luck, >>> >>> Ed >>> >>> >>> On 2/8/2013 6:12 PM, Garren Davis wrote: Been lurking on the list for a while and finally started playing with a FRK-L rubidium frequency standard. I've had this thing for a while and decided to power it up and see what it would do. I do not get a lock. What I see is the lamp voltage at 8.54 volts which I think is good but the xtal control voltage swings from 2 volts to 15 volts and back to 2 volts and keeps cycling like that. I don't have a good frequency counter but I have a 3 Ghz 40 G/sample scope and it shows that the 10 MHz signal is there. I just don't know how accurate it is. Has anyone seen a problem like this? Can anyone point me to a place to start debugging this? I have the schematics and test tools. I am a test engineer so I'm not afraid to poke around in the guts of this thing. Hopefully I can get this thing running. I also have a thunderbolt that I'll get running this weekend. I don't know how deep I'll get into this time-nuts thing but I have this nice scope and a Wavecrest sitting in my garage a > n >> d >>> I'd lik >>> e to put them to use. Any help would be appreciated. Garren >>> >>> ___ >>> time-nuts mailing list -- time-nuts@febo.com >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >> >> >> >> This message and any attached documents contain information from QLogic >> Corporation or its wholly-owned subsidiaries that may be confidential. If >> you are not the intended recipient, you may not read, copy, distribute, or >> use this information. If you have received this transmission in error, >> please notify the sender immediately by reply e-mail and then delete this >> message. >> >> ___ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > >
Re: [time-nuts] FRK-L Rubidium
Hi How old is the FRK? Does it look like it's been run without a heat sink for very long? They tend to get flaky if run for a while (many months) without heat sinking. There's nothing mysterious about it. The MTBF of the parts gets noticeably worse as the unit heats up. Bob On Feb 9, 2013, at 1:09 AM, Garren Davis wrote: > > Well for some reason the 10 Mhz stopped working on the FRK. Don't know why. > Started up the thunderbolt. It acquired satellites but then the DAC voltage > went to -5 volts. It's been there for an hour. Will this change after the > unit stabilizes? Going to bed. Will check it tomorrow. > > Garren > > > > > On Feb 8, 2013, at 8:25 PM, "Ed Palmer" wrote: > >> Hi Garren, >> >> I suggest that you get the Thunderbolt working first. Without a known 10 >> MHz source to compare to, you're flying blind. Once the Tbolt is running, >> you should be able to check the frequency of the FRK by feeding both into >> your scope. Trigger on the Tbolt and watch what the FRK does. You should >> see the trace scrolling in one direction, then slow down, then stop, then >> scroll the other direction. The 'stop' point is at 10 MHz. The frequency >> sweeps a total of 20-30 Hz so it's easy to see. If you don't see the 'stop' >> point, the FRK isn't getting to 10 MHz. Now use the best frequency counter >> you've got to measure the Tbolt. Regardless of the calibration of your >> counter, the number your counter gives you becomes your 'new' 10 MHz. Now >> measure the FRK to see if it's running fast or slow. >> >> You should check the temperature of the lamp. It's easy to get at by >> removing the cover in the center of the heat sink. Probably best to remove >> the cover and then power down before you go poking around inside! The >> temperature of the cavity is also important, but getting to it is more of a >> hassle - don't go there if you don't have to. >> >> Of course, check for the normal things like internal power supply voltages, >> ripple, current drain (both initial and steady-state), etc. >> >> Regarding your second message, yes, the adjustment under the heat sink near >> the edge is the C-field. That won't help you at this point. The adjustment >> in the center of one side is the VCO. You could try adjusting it, but like >> I said, you're flying blind at this point. You won't know if you're >> adjusting closer to 10 MHz or further away. >> >> Good luck, >> >> Ed >> >> >> On 2/8/2013 6:12 PM, Garren Davis wrote: >>> Been lurking on the list for a while and finally started playing with a >>> FRK-L rubidium frequency standard. I've had this thing for a while and >>> decided to power it up and see what it would do. I do not get a lock. What >>> I see is the lamp voltage at 8.54 volts which I think is good but the xtal >>> control voltage swings from 2 volts to 15 volts and back to 2 volts and >>> keeps cycling like that. I don't have a good frequency counter but I have a >>> 3 Ghz 40 G/sample scope and it shows that the 10 MHz signal is there. I >>> just don't know how accurate it is. Has anyone seen a problem like this? >>> Can anyone point me to a place to start debugging this? I have the >>> schematics and test tools. I am a test engineer so I'm not afraid to poke >>> around in the guts of this thing. Hopefully I can get this thing running. I >>> also have a thunderbolt that I'll get running this weekend. I don't know >>> how deep I'll get into this time-nuts thing but I have this nice scope and >>> a Wavecrest sitting in my garage an > d >> I'd lik >> e to put them to use. Any help would be appreciated. >>> >>> Garren >> >> ___ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > > > This message and any attached documents contain information from QLogic > Corporation or its wholly-owned subsidiaries that may be confidential. If you > are not the intended recipient, you may not read, copy, distribute, or use > this information. If you have received this transmission in error, please > notify the sender immediately by reply e-mail and then delete this message. > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] FRK-L Rubidium
Hi DAC clamped at -5 volts suggests that the TBolt has issues. First thing to check is the -12 volt supply. If it's missing, the DAC will indicate -5 on the screen and be sitting at 0 in real life. There are a couple other things in the DAC circuit that can make it malfunction. Bob On Feb 9, 2013, at 1:09 AM, Garren Davis wrote: > > Well for some reason the 10 Mhz stopped working on the FRK. Don't know why. > Started up the thunderbolt. It acquired satellites but then the DAC voltage > went to -5 volts. It's been there for an hour. Will this change after the > unit stabilizes? Going to bed. Will check it tomorrow. > > Garren > > > > > On Feb 8, 2013, at 8:25 PM, "Ed Palmer" wrote: > >> Hi Garren, >> >> I suggest that you get the Thunderbolt working first. Without a known 10 >> MHz source to compare to, you're flying blind. Once the Tbolt is running, >> you should be able to check the frequency of the FRK by feeding both into >> your scope. Trigger on the Tbolt and watch what the FRK does. You should >> see the trace scrolling in one direction, then slow down, then stop, then >> scroll the other direction. The 'stop' point is at 10 MHz. The frequency >> sweeps a total of 20-30 Hz so it's easy to see. If you don't see the 'stop' >> point, the FRK isn't getting to 10 MHz. Now use the best frequency counter >> you've got to measure the Tbolt. Regardless of the calibration of your >> counter, the number your counter gives you becomes your 'new' 10 MHz. Now >> measure the FRK to see if it's running fast or slow. >> >> You should check the temperature of the lamp. It's easy to get at by >> removing the cover in the center of the heat sink. Probably best to remove >> the cover and then power down before you go poking around inside! The >> temperature of the cavity is also important, but getting to it is more of a >> hassle - don't go there if you don't have to. >> >> Of course, check for the normal things like internal power supply voltages, >> ripple, current drain (both initial and steady-state), etc. >> >> Regarding your second message, yes, the adjustment under the heat sink near >> the edge is the C-field. That won't help you at this point. The adjustment >> in the center of one side is the VCO. You could try adjusting it, but like >> I said, you're flying blind at this point. You won't know if you're >> adjusting closer to 10 MHz or further away. >> >> Good luck, >> >> Ed >> >> >> On 2/8/2013 6:12 PM, Garren Davis wrote: >>> Been lurking on the list for a while and finally started playing with a >>> FRK-L rubidium frequency standard. I've had this thing for a while and >>> decided to power it up and see what it would do. I do not get a lock. What >>> I see is the lamp voltage at 8.54 volts which I think is good but the xtal >>> control voltage swings from 2 volts to 15 volts and back to 2 volts and >>> keeps cycling like that. I don't have a good frequency counter but I have a >>> 3 Ghz 40 G/sample scope and it shows that the 10 MHz signal is there. I >>> just don't know how accurate it is. Has anyone seen a problem like this? >>> Can anyone point me to a place to start debugging this? I have the >>> schematics and test tools. I am a test engineer so I'm not afraid to poke >>> around in the guts of this thing. Hopefully I can get this thing running. I >>> also have a thunderbolt that I'll get running this weekend. I don't know >>> how deep I'll get into this time-nuts thing but I have this nice scope and >>> a Wavecrest sitting in my garage an > d >> I'd lik >> e to put them to use. Any help would be appreciated. >>> >>> Garren >> >> ___ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > > > This message and any attached documents contain information from QLogic > Corporation or its wholly-owned subsidiaries that may be confidential. If you > are not the intended recipient, you may not read, copy, distribute, or use > this information. If you have received this transmission in error, please > notify the sender immediately by reply e-mail and then delete this message. > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] FRK-L Rubidium
Do you have the service manual? If not, get it here... http://www.ko4bb.com/manuals/index.php?dir=05%29_GPS_Timing/Efratom As I recall there's pretty good trouble shooting in the manual. Several years ago I fixed an FRK-H that wouldn't lock. The crystal osc had drifted enough that the trimmer didn't have enough range to tune to the lock freq. Fix was to pull one small cap that was in parallel with the trimmer. (C-11 on Osc schematic A21.) If you have a counter that you trust, it should be easy to see if tuning is reasonable. The manual will show where the trimmer is. I think I recall looking at the modulation signal as shown in fig 3-2 in the manual as I didn't have an accurately calibrated counter at the time. (I wasn't able to get to a balanced 2fm output signal until I modified the circuit.) On 2/8/2013 6:50 PM, Garren Davis wrote: I've let it run for hours and it gets warm. It has a heat sink and it all gets warm. There are two adjustment screws. One under the heat sink and one on the side of the unit. Is one for the vco and the other for the C-field? On Feb 8, 2013, at 4:53 PM, "jmfranke" wrote: How long do you let it run? Does the crystal oscillator oven get warm? If you let it run more than 15 minutes, and the oven gets hot, the next thing to check is the output frequency range as the tuning voltage sweeps. Not having a frequency counter hurts but there are other methods. One is to use WWV on 10 MHz. You should hear the output slowly sweep through WWV, first on one side of zero beat and then through zero beat to the other side. If the beat stays on one side, the VCO needs tweaking to get the sweep somewhat symmetrical about the 10 MHz WWV signal. John WA4WDL -- From: "Garren Davis" Sent: Friday, February 08, 2013 7:12 PM To: Subject: [time-nuts] FRK-L Rubidium Been lurking on the list for a while and finally started playing with a FRK-L rubidium frequency standard. I've had this thing for a while and decided to power it up and see what it would do. I do not get a lock. What I see is the lamp voltage at 8.54 volts which I think is good but the xtal control voltage swings from 2 volts to 15 volts and back to 2 volts and keeps cycling like that. I don't have a good frequency counter but I have a 3 Ghz 40 G/sample scope and it shows that the 10 MHz signal is there. I just don't know how accurate it is. Has anyone seen a problem like this? Can anyone point me to a place to start debugging this? I have the schematics and test tools. I am a test engineer so I'm not afraid to poke around in the guts of this thing. Hopefully I can get this thing running. I also have a thunderbolt that I'll get running this weekend. I don't know how deep I'll get into this time-nuts thing but I have this nice scope and a Wavecrest sitting in my garage and I'd like to put them to use. Any help would be appreciated. Garren ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] FRK-L Rubidium
Well for some reason the 10 Mhz stopped working on the FRK. Don't know why. Started up the thunderbolt. It acquired satellites but then the DAC voltage went to -5 volts. It's been there for an hour. Will this change after the unit stabilizes? Going to bed. Will check it tomorrow. Garren On Feb 8, 2013, at 8:25 PM, "Ed Palmer" wrote: > Hi Garren, > > I suggest that you get the Thunderbolt working first. Without a known 10 MHz > source to compare to, you're flying blind. Once the Tbolt is running, you > should be able to check the frequency of the FRK by feeding both into your > scope. Trigger on the Tbolt and watch what the FRK does. You should see the > trace scrolling in one direction, then slow down, then stop, then scroll the > other direction. The 'stop' point is at 10 MHz. The frequency sweeps a > total of 20-30 Hz so it's easy to see. If you don't see the 'stop' point, > the FRK isn't getting to 10 MHz. Now use the best frequency counter you've > got to measure the Tbolt. Regardless of the calibration of your counter, the > number your counter gives you becomes your 'new' 10 MHz. Now measure the FRK > to see if it's running fast or slow. > > You should check the temperature of the lamp. It's easy to get at by > removing the cover in the center of the heat sink. Probably best to remove > the cover and then power down before you go poking around inside! The > temperature of the cavity is also important, but getting to it is more of a > hassle - don't go there if you don't have to. > > Of course, check for the normal things like internal power supply voltages, > ripple, current drain (both initial and steady-state), etc. > > Regarding your second message, yes, the adjustment under the heat sink near > the edge is the C-field. That won't help you at this point. The adjustment > in the center of one side is the VCO. You could try adjusting it, but like I > said, you're flying blind at this point. You won't know if you're adjusting > closer to 10 MHz or further away. > > Good luck, > > Ed > > > On 2/8/2013 6:12 PM, Garren Davis wrote: >> Been lurking on the list for a while and finally started playing with a >> FRK-L rubidium frequency standard. I've had this thing for a while and >> decided to power it up and see what it would do. I do not get a lock. What I >> see is the lamp voltage at 8.54 volts which I think is good but the xtal >> control voltage swings from 2 volts to 15 volts and back to 2 volts and >> keeps cycling like that. I don't have a good frequency counter but I have a >> 3 Ghz 40 G/sample scope and it shows that the 10 MHz signal is there. I just >> don't know how accurate it is. Has anyone seen a problem like this? Can >> anyone point me to a place to start debugging this? I have the schematics >> and test tools. I am a test engineer so I'm not afraid to poke around in the >> guts of this thing. Hopefully I can get this thing running. I also have a >> thunderbolt that I'll get running this weekend. I don't know how deep I'll >> get into this time-nuts thing but I have this nice scope and a Wavecrest >> sitting in my garage and > I'd lik > e to put them to use. Any help would be appreciated. >> >> Garren > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > This message and any attached documents contain information from QLogic Corporation or its wholly-owned subsidiaries that may be confidential. If you are not the intended recipient, you may not read, copy, distribute, or use this information. If you have received this transmission in error, please notify the sender immediately by reply e-mail and then delete this message. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] FRK-L Rubidium
Hi Garren, I suggest that you get the Thunderbolt working first. Without a known 10 MHz source to compare to, you're flying blind. Once the Tbolt is running, you should be able to check the frequency of the FRK by feeding both into your scope. Trigger on the Tbolt and watch what the FRK does. You should see the trace scrolling in one direction, then slow down, then stop, then scroll the other direction. The 'stop' point is at 10 MHz. The frequency sweeps a total of 20-30 Hz so it's easy to see. If you don't see the 'stop' point, the FRK isn't getting to 10 MHz. Now use the best frequency counter you've got to measure the Tbolt. Regardless of the calibration of your counter, the number your counter gives you becomes your 'new' 10 MHz. Now measure the FRK to see if it's running fast or slow. You should check the temperature of the lamp. It's easy to get at by removing the cover in the center of the heat sink. Probably best to remove the cover and then power down before you go poking around inside! The temperature of the cavity is also important, but getting to it is more of a hassle - don't go there if you don't have to. Of course, check for the normal things like internal power supply voltages, ripple, current drain (both initial and steady-state), etc. Regarding your second message, yes, the adjustment under the heat sink near the edge is the C-field. That won't help you at this point. The adjustment in the center of one side is the VCO. You could try adjusting it, but like I said, you're flying blind at this point. You won't know if you're adjusting closer to 10 MHz or further away. Good luck, Ed On 2/8/2013 6:12 PM, Garren Davis wrote: Been lurking on the list for a while and finally started playing with a FRK-L rubidium frequency standard. I've had this thing for a while and decided to power it up and see what it would do. I do not get a lock. What I see is the lamp voltage at 8.54 volts which I think is good but the xtal control voltage swings from 2 volts to 15 volts and back to 2 volts and keeps cycling like that. I don't have a good frequency counter but I have a 3 Ghz 40 G/sample scope and it shows that the 10 MHz signal is there. I just don't know how accurate it is. Has anyone seen a problem like this? Can anyone point me to a place to start debugging this? I have the schematics and test tools. I am a test engineer so I'm not afraid to poke around in the guts of this thing. Hopefully I can get this thing running. I also have a thunderbolt that I'll get running this weekend. I don't know how deep I'll get into this time-nuts thing but I have this nice scope and a Wavecrest sitting in my garage and I'd lik e to put them to use. Any help would be appreciated. Garren ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] FRK-L Rubidium
I've let it run for hours and it gets warm. It has a heat sink and it all gets warm. There are two adjustment screws. One under the heat sink and one on the side of the unit. Is one for the vco and the other for the C-field? On Feb 8, 2013, at 4:53 PM, "jmfranke" wrote: > How long do you let it run? Does the crystal oscillator oven get warm? If you > let it run more than 15 minutes, and the oven gets hot, the next thing to > check is the output frequency range as the tuning voltage sweeps. Not having > a frequency counter hurts but there are other methods. One is to use WWV on > 10 MHz. You should hear the output slowly sweep through WWV, first on one > side of zero beat and then through zero beat to the other side. If the beat > stays on one side, the VCO needs tweaking to get the sweep somewhat > symmetrical about the 10 MHz WWV signal. > > John WA4WDL > > -- > From: "Garren Davis" > Sent: Friday, February 08, 2013 7:12 PM > To: > Subject: [time-nuts] FRK-L Rubidium > >> >> Been lurking on the list for a while and finally started playing with a >> FRK-L rubidium frequency standard. I've had >> this thing for a while and decided to power it up and see what it would do. >> I do not get a lock. What I see is the >> lamp voltage at 8.54 volts which I think is good but the xtal control >> voltage swings from 2 volts to 15 volts and back >> to 2 volts and keeps cycling like that. I don't have a good frequency >> counter but I have a 3 Ghz 40 G/sample scope >> and it shows that the 10 MHz signal is there. I just don't know how accurate >> it is. Has anyone seen a problem like >> this? Can anyone point me to a place to start debugging this? I have the >> schematics and test tools. I am a test >> engineer so I'm not afraid to poke around in the guts of this thing. >> Hopefully I can get this thing running. I also >> have a thunderbolt that I'll get running this weekend. I don't know how deep >> I'll get into this time-nuts thing but >> I have this nice scope and a Wavecrest sitting in my garage and I'd like to >> put them to use. Any help would be appreciated. >> >> Garren >> >> >> >> This message and any attached documents contain information from QLogic >> Corporation or its wholly-owned subsidiaries that may be confidential. If >> you are not the intended recipient, you may not read, copy, distribute, or >> use this information. If you have received this transmission in error, >> please notify the sender immediately by reply e-mail and then delete this >> message. >> ___ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > This message and any attached documents contain information from QLogic Corporation or its wholly-owned subsidiaries that may be confidential. If you are not the intended recipient, you may not read, copy, distribute, or use this information. If you have received this transmission in error, please notify the sender immediately by reply e-mail and then delete this message. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] FRK-L Rubidium
Hi First thing to check is indeed the frequency of the 10 MHz oscillator. There's a good chance it's simply aged far enough that it will no longer lock up. If the drift isn't super far, the oscillator can be adjusted. The TBolt and a good counter will tell you everything you need to know about the 10 MHz. If the oscillator is sweeping past the correct frequency, the next thing to check is the output of the SRD assembly. Your scope should be able to "see" that signal. If it's missing, then track it back down the multiplier chain. Bob On Feb 8, 2013, at 7:12 PM, Garren Davis wrote: > > Been lurking on the list for a while and finally started playing with a FRK-L > rubidium frequency standard. I've had > this thing for a while and decided to power it up and see what it would do. I > do not get a lock. What I see is the > lamp voltage at 8.54 volts which I think is good but the xtal control voltage > swings from 2 volts to 15 volts and back > to 2 volts and keeps cycling like that. I don't have a good frequency counter > but I have a 3 Ghz 40 G/sample scope > and it shows that the 10 MHz signal is there. I just don't know how accurate > it is. Has anyone seen a problem like > this? Can anyone point me to a place to start debugging this? I have the > schematics and test tools. I am a test > engineer so I'm not afraid to poke around in the guts of this thing. > Hopefully I can get this thing running. I also > have a thunderbolt that I'll get running this weekend. I don't know how deep > I'll get into this time-nuts thing but > I have this nice scope and a Wavecrest sitting in my garage and I'd like to > put them to use. Any help would be appreciated. > > Garren > > > > This message and any attached documents contain information from QLogic > Corporation or its wholly-owned subsidiaries that may be confidential. If you > are not the intended recipient, you may not read, copy, distribute, or use > this information. If you have received this transmission in error, please > notify the sender immediately by reply e-mail and then delete this message. > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] FRK-L Rubidium
How long do you let it run? Does the crystal oscillator oven get warm? If you let it run more than 15 minutes, and the oven gets hot, the next thing to check is the output frequency range as the tuning voltage sweeps. Not having a frequency counter hurts but there are other methods. One is to use WWV on 10 MHz. You should hear the output slowly sweep through WWV, first on one side of zero beat and then through zero beat to the other side. If the beat stays on one side, the VCO needs tweaking to get the sweep somewhat symmetrical about the 10 MHz WWV signal. John WA4WDL -- From: "Garren Davis" Sent: Friday, February 08, 2013 7:12 PM To: Subject: [time-nuts] FRK-L Rubidium Been lurking on the list for a while and finally started playing with a FRK-L rubidium frequency standard. I've had this thing for a while and decided to power it up and see what it would do. I do not get a lock. What I see is the lamp voltage at 8.54 volts which I think is good but the xtal control voltage swings from 2 volts to 15 volts and back to 2 volts and keeps cycling like that. I don't have a good frequency counter but I have a 3 Ghz 40 G/sample scope and it shows that the 10 MHz signal is there. I just don't know how accurate it is. Has anyone seen a problem like this? Can anyone point me to a place to start debugging this? I have the schematics and test tools. I am a test engineer so I'm not afraid to poke around in the guts of this thing. Hopefully I can get this thing running. I also have a thunderbolt that I'll get running this weekend. I don't know how deep I'll get into this time-nuts thing but I have this nice scope and a Wavecrest sitting in my garage and I'd like to put them to use. Any help would be appreciated. Garren This message and any attached documents contain information from QLogic Corporation or its wholly-owned subsidiaries that may be confidential. If you are not the intended recipient, you may not read, copy, distribute, or use this information. If you have received this transmission in error, please notify the sender immediately by reply e-mail and then delete this message. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] FRK-L Rubidium
Been lurking on the list for a while and finally started playing with a FRK-L rubidium frequency standard. I've had this thing for a while and decided to power it up and see what it would do. I do not get a lock. What I see is the lamp voltage at 8.54 volts which I think is good but the xtal control voltage swings from 2 volts to 15 volts and back to 2 volts and keeps cycling like that. I don't have a good frequency counter but I have a 3 Ghz 40 G/sample scope and it shows that the 10 MHz signal is there. I just don't know how accurate it is. Has anyone seen a problem like this? Can anyone point me to a place to start debugging this? I have the schematics and test tools. I am a test engineer so I'm not afraid to poke around in the guts of this thing. Hopefully I can get this thing running. I also have a thunderbolt that I'll get running this weekend. I don't know how deep I'll get into this time-nuts thing but I have this nice scope and a Wavecrest sitting in my garage and I'd like to put them to use. Any help would be appreciated. Garren This message and any attached documents contain information from QLogic Corporation or its wholly-owned subsidiaries that may be confidential. If you are not the intended recipient, you may not read, copy, distribute, or use this information. If you have received this transmission in error, please notify the sender immediately by reply e-mail and then delete this message. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
