[Elecraft] K2 No SSB output power with new SSB board fitted.
Everything setup to the point of ‘Fine carrier Balance Adjustment. But no RF output. The SSBA BAL adjustment worked fine so there must be a low level SSB signal to be fed back to the Rx. Current jumps from 222mA to 398mA on activating PTT. No increase with audio input, no S meter indication or indication in wattmeter. New SSB board swapped out with known working one from another rig. The newly built board works fine in the other rig. Known good board does not work in newly built rig. Stating the obvious the SSB boards are fine there is something up with the new rig. CW works ok with full output power. Mike is Elecraft MH4. Continuity of AF pin1 confirmed up to pin5 of J11. W2 and W3 removed, also C167. -- __ 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 - Stumble at the last hurdle.
This is my 2nd K2 build this year. This fantastic kit has kept me sane. I tested every component on an LCR meter (found RFC10 open) and tried to work as slowly as possible. I got to the end of the build to the very last alignment step.-- The adjustment of C44 and C46 for the 12 meter band and I can only get 0.2W. 10 meters is fine with adjusting L12 and L13 but 12 meters (which I do not use but it should work) is nada. I had the exact same problem on 20meters but careful tweaking of C21/23 and L8/9 and it burst into life. When testing the capacitors I noticed they had quite a wide tolerance range. Could the band pass range for the 10 and 12 meter bands be too high? Any ideas would be appreciated. I am quite good at wondering down rabbit holes. Rgds. Mark G4RUR Das Beste Oder Nichts __ 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] KSB2 problems in K2 transceiver
Today I finished the KSB2 adapter and installed it into my K2. It worked first time but was intermittent. I found the issue as I had omitted to solder the outer top pins of the twin three pin interconnects. That done everything seems ok and then No Apparent RF output. USB/LSB/CW Pressing TUNE produced a max of 0.8W. VOX would trip to transmit but the S meter showed no modulation. Coarse carrier balance adjustment worked but zero S meter readings was very wide (unlike earlier when it was a fine, narrow adjustment) All voltages looked slightly low but ball park on the KSB2 board except for U2 (the DAC) Pin5 which is ALC THR. This was sitting at 5.89v rather than 0.6 on both RX and TX. I have removed the KSB2 and full CW power output can now be achieved which is a relief. I will examine everything under a microscope again but has anyone any suggestions? I suspect ALC to be the culprit but how to investigate? Thanks Mark G4RUR -- If you are afraid you are living in the future. If you are sad you are living in the past. If you are content you are living in the now. __ 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.Unable to undertake VCO alignment.
Issue. Unable to undertake VCO alignment. Voltage at R30 fixed at 24mV. The VCO oscillator test (Alignment and test Part II p 63) has passed. Well the frequency is 7.98MHz rather than 8->10 but that conceivably could be within the bounds of measurement error. In the VCO alignment test a DMM (Keysight U1271) clamped onto the left side end of R30 reads 24mV no matter what the setting of L30. I have looked everywhere over the appropriate circuitry but can see no issues. Including triple checking T5 which is 100% wound and fitted properly. I made the measurements from troubleshooting (PLL Reference Oscillator and VCO P 10) and got:- Reference Oscillator Output 0.72 VCO Output 0.24 VCO Buffer Output 0.59 All measurements are at the low end of the acceptable range but just in spec. I measured voltages in the area and have noted the following:- 1. U4 (MC145170) pin 7 CLK/SCK is at 5v as against the specified 0v. 2. U4 pin 13 PDOUT is at 5v rather than 4v. This feeds the inverting input of U6B causing the output to be low. 3. The gate input of Q18 is 0 rather than -1. I am at a loss as to what to check next and any suggestions would be most welcome. BTW I also have a ½ decent scope so can probe with that assuming I can figure out what I should be seeing. The K2 is a brilliant kit but seriously different to tube amps. which is my usual playpen. Thanks -- If you are afraid you are living in the future. If you are sad you are living in the past. If you are content you are living in the now. __ 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
