Re: [Elecraft] K2 Only 30-metre Band Works
Don, I borrowed a couple of new relays from my KAT2 kit. I installed K1 and K2 with the correct orientation this time. This immediately resolved all transmit and receive problems. I have pushed on to successfully build the KNB2, KBT2 and I'm now working on the KSB2. No further problems have been found. The K160RX, KAT2 and KIO2 will follow these. My replacement relays are on the way to me from Elecraft. I'm having fun again. I have downloaded Spectrogram and I'll use it for filter alignment as soon as I complete the KSB2 just to be thorough but I'm already happy with the way the K2 is working. I've also bookmarked your web page since I see lots of useful articles. This email list sure is a useful resource. 73, Murray VA1CQ -- This email has been checked for viruses by AVG. https://www.avg.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] K2 Only 30-metre Band Works
Jerry, I tried briefly to remove the relay for re-use. I decided quickly, however, after starting with my equipment on hand and skill level, it made more sense to go for full demolition since the cost of replacement is low. I will keep your method in mind for future. I have found when removing a 2-pin device that rocking the device back and forth while heating works to remove 1 pin followed by heating the other pin, rocking and pulling out the device. My current solder sucker is OK but not up the task of removing a multipin device like these relays. 73, Murray VA1CQ -- This email has been checked for viruses by AVG. https://www.avg.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] K2 Only 30-metre Band Works
Jerry, I have had only marginal success with the Soldapullt, but I have a Hakko 808 that works very well - with the correct tip it does the job nicely - it heats and then you pull the trigger to extract the solder. Not inexpensive, but when I was doing repairs on a daily basis, it was a godsend. 73, Don W3FPR On 7/3/2021 7:57 PM, jerry wrote: On 2021-07-03 11:03, VA1CQ wrote: Any tips on removing them would be appreciated. *** Crush them with a pair of pointy vise-grips? Of course, I'd try desoldering them first. Hold the heat on a bit longer than seems necessary, because you need to melt that solder all the way to the other side of the board. When the hole is nice and clean around the pin, take your needlenose pliers and wiggle the pin back & forth. You'll be able to tell when it's really free. The main catastrophe to avoid is tearing out the plated through hole. If you don't have one, it's hard to beat a Soldapullt. Get a real one, not a clone. - Jerry KF6VB __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] K2 Only 30-metre Band Works
On 2021-07-03 11:03, VA1CQ wrote: Any tips on removing them would be appreciated. *** Crush them with a pair of pointy vise-grips? Of course, I'd try desoldering them first. Hold the heat on a bit longer than seems necessary, because you need to melt that solder all the way to the other side of the board. When the hole is nice and clean around the pin, take your needlenose pliers and wiggle the pin back & forth. You'll be able to tell when it's really free. The main catastrophe to avoid is tearing out the plated through hole. If you don't have one, it's hard to beat a Soldapullt. Get a real one, not a clone. - Jerry KF6VB __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] K2 Only 30-metre Band Works
Don, I took your advice and crushed those two relays. Even doing that, it was tough enough to get both relays out and clean out the solder pad holes. It's done and the K2 is ready for me to pop in two new relays. I even used a couple toothpicks in the process. I confirmed the stenciled outlines were correct on the PCB. I've been on the Elecraft site and I've got my shopping cart ready with those relays plus a few other spare parts. I powered up the K2 with the two missing relays. Of course, 80 and 40 metres don't work as expected. But every band from 30 to 10 metres seems to be working perfectly now in both receive and transmit. I've never been so happy to hear QRM and band noise. The DX is rolling in. The trimmer caps work just as they are supposed to in the bandpass filters for 20, 17 and 12 metres. A side benefit is I sure know the K2 circuits better now than I did a few days ago after all the time I spent studying the schematics. I will push on building the various accessories I have while I wait for my order to arrive from Elecraft so I can complete the K2 build. 73, Murray VA1CQ -- This email has been checked for viruses by AVG. https://www.avg.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] K2 Only 30-metre Band Works
Murray,
Yes, Elecraft has those relays.
If you do not have adequate desoldering gear, the the best way to remove
them is to crush the case so you can remove the pins one at a time.
Clean up with solder wick and if solder remains in the holes, push it
out with a wooden toothpick. Use whatever tool works to crush the relay
cases.
73,
Don W3FPR
On 7/3/2021 2:03 PM, VA1CQ wrote:
Hi Don,
I have discovered I installed K1 and K2 backwards. The location bar on
each relay is facing in the opposite direction ("down") from the other
relays. The manual Parts Placement Drawing clearly shows all relays
oriented vertically must have the bar on the relay at the "top". I
can't imagine why I did that. Unless the stenciling on the PCB is
wrong (highly unlikely), then it's my fault for not following the
manual. I can't see the PCB stenciling now since the relay covers it.
This explains why I could not tune the 40 metre band. And probably
explains other things I couldn't do too. I discovered this when I
started measuring voltages around K1.
This will be difficult to correct. The two relays are flush with the
board. I can't cut them off since I have no access to their pins. I
will need to solder suck and wick them out. Fortunately, their pins
are not bent but straight through their solder pads.
Any tips on removing them would be appreciated. I'm hoping these or
similar parts are still available.
73,
Murray VA1CQ
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Re: [Elecraft] K2 Only 30-metre Band Works
Hi Don,
I have discovered I installed K1 and K2 backwards. The location bar on
each relay is facing in the opposite direction ("down") from the other
relays. The manual Parts Placement Drawing clearly shows all relays
oriented vertically must have the bar on the relay at the "top". I can't
imagine why I did that. Unless the stenciling on the PCB is wrong
(highly unlikely), then it's my fault for not following the manual. I
can't see the PCB stenciling now since the relay covers it.
This explains why I could not tune the 40 metre band. And probably
explains other things I couldn't do too. I discovered this when I
started measuring voltages around K1.
This will be difficult to correct. The two relays are flush with the
board. I can't cut them off since I have no access to their pins. I will
need to solder suck and wick them out. Fortunately, their pins are not
bent but straight through their solder pads.
Any tips on removing them would be appreciated. I'm hoping these or
similar parts are still available.
73,
Murray VA1CQ
--
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Re: [Elecraft] K2 Only 30-metre Band Works
Murray, The 7.6 volts on the 8 volt power rail is not a problem. The relays operate on 5 volts output from U1. It is possible that the relays have developed oxidation - if there is any damage to the relay case. Otherwise, the relay contacts should be good - they are good for more than 100k operations. Try the proper bandpass filter alignment. Follow the band order shown in the manual - it is important. The inductors must be aligned before the capacitors (to do otherwise will end up with you 'chasing your tail'). If you do not have indicated power output, put your RF Probe on W6 and align the bandpass filters for maximum RF voltage on each band. 73, Don W3FPR On 7/2/2021 8:54 PM, VA1CQ wrote: Hi Geert, Coincidentally, while troubleshooting today I was listening to relays! There is a different sound depending on whether one relay clicks or more than one clicks. Yes, there are relays clicking as I change the band. A different number of relays operate depending on which band you change to. The schematic shows which relays close as you change bands. I was suspicious that maybe the necessary relay contacts were not closing. If there is relay closing trouble, this could explain why the different bandpass filters are not working correctly. Some history. I bought this K2 new in 2008. It sat unbuilt for about 10 years. I then built the Control board only. After that a couple more years passed. Just this year I built the Front Panel and RF boards. Therefore all parts are at least 13 years old. I wondered if over that time perhaps the relay contacts may have aged through lack of use. Today I now have 80, 30 and 15 metre bands working. I was able to tune the matching bandpass filters to get the correct transmit output power on each of these bands. But I still cannot get 40, 20, 17, 12 and 10 metres to function. I did some resoldering and even took off the heatsink to examine the underside of the RF board. I did more voltage checking today. I came to no conclusions but I still am wondering why the 8 volt bus is only 7.6 volts and whether this could be an issue or possibly cause unpredictable switching. I will continue studying the relays further in my next troubleshooting session. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] K2 Only 30-metre Band Works
Hi Geert, Coincidentally, while troubleshooting today I was listening to relays! There is a different sound depending on whether one relay clicks or more than one clicks. Yes, there are relays clicking as I change the band. A different number of relays operate depending on which band you change to. The schematic shows which relays close as you change bands. I was suspicious that maybe the necessary relay contacts were not closing. If there is relay closing trouble, this could explain why the different bandpass filters are not working correctly. Some history. I bought this K2 new in 2008. It sat unbuilt for about 10 years. I then built the Control board only. After that a couple more years passed. Just this year I built the Front Panel and RF boards. Therefore all parts are at least 13 years old. I wondered if over that time perhaps the relay contacts may have aged through lack of use. Today I now have 80, 30 and 15 metre bands working. I was able to tune the matching bandpass filters to get the correct transmit output power on each of these bands. But I still cannot get 40, 20, 17, 12 and 10 metres to function. I did some resoldering and even took off the heatsink to examine the underside of the RF board. I did more voltage checking today. I came to no conclusions but I still am wondering why the 8 volt bus is only 7.6 volts and whether this could be an issue or possibly cause unpredictable switching. I will continue studying the relays further in my next troubleshooting session. 73, Murray VA1CQ -- This email has been checked for viruses by AVG. https://www.avg.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] K2 Only 30-metre Band Works
Further troubleshooting of my new K2 build reveals that transmit and receive on the 30-metre band works well. But all other bands, transmit and receive, don't work. ... I am trying to think of what's common among all bands except 30 metres, transmit and receive, where a problem could lie. The fact that 30 metres works OK confirms that much of the rig is working correctly. Since 30 and 20 metres share a band-pass filter as well as a low pass filter makes this all the more confusing. The K2 uses latching relays for band switching (as well as VFO switching, ext ant switching and some other things). So, if your K2 can't drive its relays (or no longer can drive its relays) then many things still work, except band switching. All of this is driven from U1 on the main board. U1 has a separate voltage regulator, U2. I am pretty sure that the main CPU on the control board yells at you if it can't talk to the IO controller U1 on the main board. But perhaps the voltage is good enough for the controller to work but not for the relays to operate. If you change bands, do you hear the relays operate? After you change bands, after a second or so, you should hear a distinct "lickkk" as several relays are changed. Also, since you are measuring, can you verify that if you change bands, the relays switch as expected? When looking at the 2005 schematics, I see that all relays - even on optional modules like the 160m module, have a voltage "RY COM" to switch against (mainboard, sheet 3). The schematic says that if one relay needs to be operated, all the other relays are pulled in the other direction. I would make sure that this "RY COM" isn't grounded or something. 73, Geert Jan PE1HZG __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] K2 Only 30-metre Band Works
Hi Jerry, Your advice is good. I never did get that soldering iron technique to work for stripping the toroid wire. I used the fine sandpaper supplied with the K2 to manually bare each wire end. After I soldered, for each connection, I checked using an ohm meter for continuity between solder pads at each end of the toroid wire on the board (not between the wires). I figured this should confirm that the toroid wire was in fact connected to its solder pad. 73, Murray VA1CQ -- This email has been checked for viruses by AVG. https://www.avg.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] K2 Only 30-metre Band Works
Hi Don, I forgot to add my name or call on my last post. I agree with that policy. Yes, the K2 seems to be fully operational on 30 metres. I even briefly tried setting 10 W transmit power and it actually transmitted at 10 watts. I was able to tweak the 30 metre bandpass filter and I could see the transmit power reaching a peak and then decreasing as I tuned. I see this same effect when receiving from the antenna on 30 metres. I already know that on the bands which are not operating (all except 30 metres) that tuning the bandpass filters has no effect on either transmit output or on receive signal levels from an antenna. Adjusting the filters produces no RF voltage at W6. Regardless how I tune the filters, the K2 indicates the transmit power is 0.1 to 0.2 watts. It never changes. I notice that my 8 volt regulator output is 7.6 volts. Considering I am using an input voltage to the transceiver of 13.6 volts, isn't 7.6 volts a little low for a regulated output? By comparison, the 5 volt regulator output is 4.92 volts. The manual suggests current draw may be too large if the 8 volt line drops to 7.5 volts or lower. The manual even suggests changing the regulator if a reason can't be found for its voltage being below 7.5 volts. 73, Murray VA1CQ -- This email has been checked for viruses by AVG. https://www.avg.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] K2 Only 30-metre Band Works
I would suggest that since 30 meters is working OK, the K2 is capable of both transmit and receive. Furthermore, I would expect the problem to be in the bandpass filter tuning. Be certain to follow the band order for tuning, otherwise you will be chasing your tail. Use the RP Probe (provided with the K2 kit) to measure RF voltage. If the bandpass filter adjustment does not provide adequate Power Output, put the RF Probe on W6 while making the adjustments to the bandpass filter. Tune the bandpass filter for maximum RF voltage at W6. Then look at the power output. You may want to 'tweek' the bandpass filter a bit, but it should be very close to correct. Your name and call on your posts please - I know your call is in your email address, but your name would make it a bit more personal. 73, Don W3FPR On 7/1/2021 5:34 PM, VA1CQ wrote: Further troubleshooting of my new K2 build reveals that transmit and receive on the 30-metre band works well. But all other bands, transmit and receive, don't work. On transmit on non-working bands, the output signal doesn't make it past the output of the band-pass filters (W6). But on 30 metres, the band-pass filter output is in the correct range of 25 mV with 5 watts of transmit power. On 30 metres, the band-pass coils tune as you would expect and I can peak the band on receive and transmit. On receive on 30 metres, I can hear RTTY, CW and WWV as well as SW stations in the 31-metre band. On other bands, I hear nothing except on 40 metres at night when signals are strongest. I can hear an occasional strong station on 40. When transmitting, I am using the DL-1 dummy load. I am trying to think of what's common among all bands except 30 metres, transmit and receive, where a problem could lie. The fact that 30 metres works OK confirms that much of the rig is working correctly. Since 30 and 20 metres share a band-pass filter as well as a low pass filter makes this all the more confusing. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] K2 Only 30-metre Band Works
On 2021-07-01 14:34, VA1CQ wrote: Further troubleshooting of my new K2 build reveals that transmit and receive on the 30-metre band works well. But all other bands, transmit and receive, don't work. *** I would carefully check the connections to the toroids. Yeah, that procedure for stripping the wire ends with a soldering iron works every time. Except when it doesn't. - Jerry KF6VB ( who remembers - without fondness - his one-time job troubleshooting passive filters in the telephone factory ) __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
[Elecraft] K2 Only 30-metre Band Works
Further troubleshooting of my new K2 build reveals that transmit and receive on the 30-metre band works well. But all other bands, transmit and receive, don't work. On transmit on non-working bands, the output signal doesn't make it past the output of the band-pass filters (W6). But on 30 metres, the band-pass filter output is in the correct range of 25 mV with 5 watts of transmit power. On 30 metres, the band-pass coils tune as you would expect and I can peak the band on receive and transmit. On receive on 30 metres, I can hear RTTY, CW and WWV as well as SW stations in the 31-metre band. On other bands, I hear nothing except on 40 metres at night when signals are strongest. I can hear an occasional strong station on 40. When transmitting, I am using the DL-1 dummy load. I am trying to think of what's common among all bands except 30 metres, transmit and receive, where a problem could lie. The fact that 30 metres works OK confirms that much of the rig is working correctly. Since 30 and 20 metres share a band-pass filter as well as a low pass filter makes this all the more confusing. -- This email has been checked for viruses by AVG. https://www.avg.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
