[time-nuts] Racal 1992 input amplifier offset problem - fixed
I am happy to report that the offset problem I mentioned on Dec 28 is fixed. There were no responses to my request, but it might be helpful to others should their 1992 get faulty in the same way. Basically the A-input had a low leakage input protection diode (JPAD50) that was, well, not so low leakage anymore. Should it have broken down completely the problem would probably have been more easy to spot. Anyway, it is replaced with a BAS116. Offset and sensitivity calibration went fine and operation is back to normal. Joop ___ 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] Racal 1992 input amplifier offset problem
Hi, Sorry if this question is a bit out of place. It is not about timing, but more an electronics thing. But searching for Racal 1992 seems to get a lot of hits here on this list. I have just received a used Racal 1992 counter and are checking it for proper operation. All seem fine except the channel A only triggers properly on small signals with DC input or when in "auto-trigger" mode selecting AC. Checking the trigger level in this mode shows -1.08 (Volts I guess) I went through the protocol for channel-A adjustment with R192/R149 and channel-B adjustment with R193/R150. Channel B seems to work fine and needed only minor adjustment. The offset can be adjusted to 0V and the specified sensitivity levels of 13mV (count) and 7mV (gate off) are fine. Changing from AC to DC has no effect, both work fine here. However channel A seems to have a problem. It is not possible to adjust it to 0V in AC mode. Only with DC it can be adjusted to 0. Sensitivity is also a bit out of range. I get 17mV (count is steady) and 7mV (gate off). The trigger output levels at the back seem ok for both channels (about +5.1 to -5.1) So I guess the DAC is still OK. Looking at the schematics I suspect IC34 (CA3140E) might be having a problem, but I did not dare to open the module yet. Is it placed in a socket? Has anybody experienced a similar problem and fixed it? Are some capacitors known to go bad? Any help would be appreciated. Cheers, Joop ___ 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] Racal 1992
mine 1992 (S/N: 992064) mounts a 9462 (454879, REV A) 5MHz OCXO: any more info about it? _ Elio. ___ 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] Racal 1992 drift after standby
Antonio, I will have a look this weekend when I'm back home so I can read the manual and/or open the counter to find the jumper... Harry - PE1OXP > Thanks, Harry, I already had got this info from this list, but had trouble > locating the jumper. The manuals seemed ambiguous, and I didn't find > anyone who actually made the change. May you help? Anyway, now my programs > are MATE/CIIL ... > > Antonio I8IOV > >> You can switch the mode to standard language instead of MATE/CIIL by >> changing a jumper inside the counter. >> >> 73, Harry - PE1OXP >> > > > ___ > 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] Racal 1992 drift after standby
Thanks, Harry, I already had got this info from this list, but had trouble locating the jumper. The manuals seemed ambiguous, and I didn't find anyone who actually made the change. May you help? Anyway, now my programs are MATE/CIIL ... Antonio I8IOV > You can switch the mode to standard language instead of MATE/CIIL by > changing a jumper inside the counter. > > 73, Harry - PE1OXP > ___ 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] Racal 1992 drift after standby
You can switch the mode to standard language instead of MATE/CIIL by changing a jumper inside the counter. 73, Harry - PE1OXP > In my experience limited to two units, the 04E works very well, and I've > been prudent claiming an aging of one part in 10E10 per day. I suggest to > check your unit. My reference was Rb (LPRO). They are both 02M. > The 02M has a tag on the left side looking from the front. If the tag was > lost, there are two holes. 02M uses the military GPIB language > (MATE/CIIL), and, as far as I know, doesn't respond to the standard 1992 > language. > It exists an enanched version of the 04E, that is the 04ES, but AFAIK it > was available only in England. > At power on, I read 1992 first, then 8572 0404. > > Antonio I8IOV > >> Ed,Mine comes out of standby pretty much where it is going to be. I see >> from >> information posted that I seem to have option 4E. Mine doesn't look >> quite >> that good compared to GPS. I believe mine is an 02M model though there >> is >> nothing on the unit to say so. The manual says the GPIB should be a >> 401820 >> but mine is labeled 411820. Maybe a later version. I haven't had time to >> hook a GPIB controller to it yet. Maybe next week. >> ___ >> 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 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] Racal 1992 drift after standby
In my experience limited to two units, the 04E works very well, and I've been prudent claiming an aging of one part in 10E10 per day. I suggest to check your unit. My reference was Rb (LPRO). They are both 02M. The 02M has a tag on the left side looking from the front. If the tag was lost, there are two holes. 02M uses the military GPIB language (MATE/CIIL), and, as far as I know, doesn't respond to the standard 1992 language. It exists an enanched version of the 04E, that is the 04ES, but AFAIK it was available only in England. At power on, I read 1992 first, then 8572 0404. Antonio I8IOV > Ed,Mine comes out of standby pretty much where it is going to be. I see from > information posted that I seem to have option 4E. Mine doesn't look quite > that good compared to GPS. I believe mine is an 02M model though there is > nothing on the unit to say so. The manual says the GPIB should be a 401820 > but mine is labeled 411820. Maybe a later version. I haven't had time to > hook a GPIB controller to it yet. Maybe next week. > ___ > 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] Racal 1992
Hi, A year or so back I had an unusual fault on my 1991 (160MHz version of the 1992). After half-an-hour it would lock-up if you changed any settings but was okay if you left it alone. Of course, after a cool-down period, all went well until the next time. Now for some reason I got it into my head that it was the GPIB board giving me grief so I put the 10x scope probe on a buss line going to it from IC18 on the motherboard. Instantly the fault appeared and it then became apparent there wasn't enough poke to run both the counter and the few pF of the scope lead. To cut a long story short, the supply pin was bent under at 90 degrees so the chip was working without any external power, just on internal leakages, until it warmed up. Had it been IC18 - good bye Mr. Chips. Cheers - Joe G3LLV ___ 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] Racal 1992 drift after standby
Ed,Mine comes out of standby pretty much where it is going to be. I see from information posted that I seem to have option 4E. Mine doesn't look quite that good compared to GPS. I believe mine is an 02M model though there is nothing on the unit to say so. The manual says the GPIB should be a 401820 but mine is labeled 411820. Maybe a later version. I haven't had time to hook a GPIB controller to it yet. Maybe next week. ___ 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] Racal 1992
Hi Alan, I have the same info, but it's collected from multiple sources. I haven't seen all of it in one official source. I'd like to see it and I'm sure others would as well. Ed Alan Melia wrote: Hi Ed I dont know whther it would be of interest but i have a page from a cat with the comparative specs for those OXCOs Alan G3NYK - Original Message - From: "Ed Palmer" To: "Time Nuts Mailing List" Sent: Thursday, August 27, 2009 6:52 PM Subject: Re: [time-nuts] Racal 1992 John Green wrote: Ed Palmer wrote:Which timebase does yours have? I've got option 4E (similar to 4B). Although the timebase appears to be stable, I've noticed that the counter drifts about 5e-9 during warmup, even when the oscillator has been on standby for many days. It takes a couple of hours to settle down. Does yours do anything similar? Ed, Exactly which reference I have seems to be something of a mystery. The part number on it is 454879. The part number listed in my manual is 404386. My manual makes no reference to optional timebases. The manual I downloaded does but doesn't list the part number I have as a choice. Though it is ovenized, I don't believe it is the best high stability type. It does look pretty good in general terms. Retrace is important to me and it seems pretty good in this respect. I did try to get it in sync with the GPSDO and after several minor adjustments and several hours of observation, I still saw movement. This isn't that important as I can always use the GPSDO as a standard. I did find out why it doesn't output a sine wave. There is a nice sine wave out of the oscillator itself but that goes through a conditioning amplifier and into IC39 which is some kind of 40 pin device. IC39 actually feeds the back panel BNC. Why they do this is beyond me but it answers the question. I haven't looked at how it behaves coming out of standby yet. I'll let you know when I have done that. Yes, they seem to have made a few oscillator substitutions along the way. I'm guessing that they outsourced the oscillators and changed suppliers a few times during the life of the 1991/1992 product. I have two units, one labelled as having 04A and the other having 04E. Pulling info from various manuals, data sheets, and my units, I think the info is as follows: Option Osc. Part # Physical Description - based on my oscillators only 04A 9444* or 11-1710 Approx. cube 5 cm., only one adjustment 04B 9423 Don't know - haven't seen one of these 04E 9462* or 404386 or 454879* Approx 5x5x10cm., two adjustments * these are the markings on my oscillators. The 04E oscillator is actually labelled "9462 454879, Rev. A ERC 87-34". Both of my oscillators are 5 MHz with freq. doubler boards attached to the bottom. IC39 is one of the "Magic happens here" chips in these units. One of my units died shortly after I got it. IC39 didn't let the magic smoke out, but it was running at a temperature of ~90C! IC39 in the other unit was running at ~60C. I decided to put a heat sink on it just in case. Ed ___ 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] Racal 1992
Hi Ed I dont know whther it would be of interest but i have a page from a cat with the comparative specs for those OXCOs Alan G3NYK - Original Message - From: "Ed Palmer" To: "Time Nuts Mailing List" Sent: Thursday, August 27, 2009 6:52 PM Subject: Re: [time-nuts] Racal 1992 > John Green wrote: > > Ed Palmer wrote:Which timebase does yours have? I've got option 4E (similar > > to 4B). > > Although the timebase appears to be stable, I've noticed that the > > counter drifts about 5e-9 during warmup, even when the oscillator has > > been on standby for many days. It takes a couple of hours to settle > > down. Does yours do anything similar? > > > > > > > > Ed, Exactly which reference I have seems to be something of a mystery. The > > part number on it is 454879. The part number listed in my manual is 404386. > > My manual makes no reference to optional timebases. The manual I downloaded > > does but doesn't list the part number I have as a choice. Though it is > > ovenized, I don't believe it is the best high stability type. It does look > > pretty good in general terms. Retrace is important to me and it seems pretty > > good in this respect. I did try to > > get it in sync with the GPSDO and after several minor adjustments and > > several hours of observation, I still saw movement. This isn't that > > important as I can always use the GPSDO as a standard. > > I did find out why it doesn't output a sine wave. There is a nice sine wave > > out of the oscillator itself but that goes through a conditioning amplifier > > and into IC39 which is some kind of 40 pin device. IC39 actually feeds the > > back panel BNC. Why they do this is beyond me but it answers the question. > > I haven't looked at how it behaves coming out of standby yet. I'll let you > > know when I have done that. > > > > Yes, they seem to have made a few oscillator substitutions along the > way. I'm guessing that they outsourced the oscillators and changed > suppliers a few times during the life of the 1991/1992 product. I have > two units, one labelled as having 04A and the other having 04E. Pulling > info from various manuals, data sheets, and my units, I think the info > is as follows: > > Option Osc. Part # Physical Description - based on my oscillators only > 04A 9444* or 11-1710 Approx. cube 5 cm., only one adjustment > 04B 9423 Don't know - haven't seen one of these > 04E 9462* or 404386 or 454879* Approx 5x5x10cm., two adjustments > > * these are the markings on my oscillators. The 04E oscillator is > actually labelled "9462 454879, Rev. A ERC 87-34". Both of my > oscillators are 5 MHz with freq. doubler boards attached to the bottom. > > IC39 is one of the "Magic happens here" chips in these units. One of my > units died shortly after I got it. IC39 didn't let the magic smoke out, > but it was running at a temperature of ~90C! IC39 in the other unit was > running at ~60C. I decided to put a heat sink on it just in case. > > Ed > > > ___ > 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] Racal 1992
John Green wrote: Ed Palmer wrote:Which timebase does yours have? I've got option 4E (similar to 4B). Although the timebase appears to be stable, I've noticed that the counter drifts about 5e-9 during warmup, even when the oscillator has been on standby for many days. It takes a couple of hours to settle down. Does yours do anything similar? Ed, Exactly which reference I have seems to be something of a mystery. The part number on it is 454879. The part number listed in my manual is 404386. My manual makes no reference to optional timebases. The manual I downloaded does but doesn't list the part number I have as a choice. Though it is ovenized, I don't believe it is the best high stability type. It does look pretty good in general terms. Retrace is important to me and it seems pretty good in this respect. I did try to get it in sync with the GPSDO and after several minor adjustments and several hours of observation, I still saw movement. This isn't that important as I can always use the GPSDO as a standard. I did find out why it doesn't output a sine wave. There is a nice sine wave out of the oscillator itself but that goes through a conditioning amplifier and into IC39 which is some kind of 40 pin device. IC39 actually feeds the back panel BNC. Why they do this is beyond me but it answers the question. I haven't looked at how it behaves coming out of standby yet. I'll let you know when I have done that. Yes, they seem to have made a few oscillator substitutions along the way. I'm guessing that they outsourced the oscillators and changed suppliers a few times during the life of the 1991/1992 product. I have two units, one labelled as having 04A and the other having 04E. Pulling info from various manuals, data sheets, and my units, I think the info is as follows: Option Osc. Part # Physical Description - based on my oscillators only 04A 9444* or 11-1710 Approx. cube 5 cm., only one adjustment 04B 9423 Don't know - haven't seen one of these 04E 9462* or 404386 or 454879* Approx 5x5x10cm., two adjustments * these are the markings on my oscillators. The 04E oscillator is actually labelled "9462 454879, Rev. A ERC 87-34". Both of my oscillators are 5 MHz with freq. doubler boards attached to the bottom. IC39 is one of the "Magic happens here" chips in these units. One of my units died shortly after I got it. IC39 didn't let the magic smoke out, but it was running at a temperature of ~90C! IC39 in the other unit was running at ~60C. I decided to put a heat sink on it just in case. Ed ___ 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] Racal 1992
Ed Palmer wrote:Which timebase does yours have? I've got option 4E (similar to 4B). Although the timebase appears to be stable, I've noticed that the counter drifts about 5e-9 during warmup, even when the oscillator has been on standby for many days. It takes a couple of hours to settle down. Does yours do anything similar? Ed, Exactly which reference I have seems to be something of a mystery. The part number on it is 454879. The part number listed in my manual is 404386. My manual makes no reference to optional timebases. The manual I downloaded does but doesn't list the part number I have as a choice. Though it is ovenized, I don't believe it is the best high stability type. It does look pretty good in general terms. Retrace is important to me and it seems pretty good in this respect. I did try to get it in sync with the GPSDO and after several minor adjustments and several hours of observation, I still saw movement. This isn't that important as I can always use the GPSDO as a standard. I did find out why it doesn't output a sine wave. There is a nice sine wave out of the oscillator itself but that goes through a conditioning amplifier and into IC39 which is some kind of 40 pin device. IC39 actually feeds the back panel BNC. Why they do this is beyond me but it answers the question. I haven't looked at how it behaves coming out of standby yet. I'll let you know when I have done that. ___ 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.
