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Dear all,
I own a K2 s/n 4926 since 5 years. It was working fine until last week, when after being unused for some months was back powered on for the IOTA contest. After 3 minutes of power applied during normal rx operation some smoke was coming out from the back top of the KPA100. After investigation I found C24, 10nF 50V capacitor on KPA100 burned out. I replaced it and the KPA100 passed the preliminary checks, and no other damages were found. Re-applying the power everything was ok, except that going to CW in test mode and keying the K2 with the paddle, no sidetone was appearing. So I checked the K2 manual in the troubleshhoting section for sidetone, and I found that the U8 pin 4, raised to isolate it from 2N7000 gate, UPO digital output of the MAX534, doesn´t produce the sidetone square wave filtered (it stays always to 0 even keying the K2) then from U10B filter and then injected in the AF chain after the volume control.
I tried also to see if it was a problem in sw settings, but my firmware version 2.04 doesn´t have the ST P option to change the source of sidetone, so that was not a problem.
The 2N7000 seems ok. So I suspect a wrong behaviour of MAX 534, even if the rest of the DAC analog outputs are working fine, including sidetone volume control, or a firmware and MCU problem, even if the rest of the K2 seems to work fine.
Any good suggestions for my poor K2 ?
Thanks a lot
73 de Stefano, IV3LZQ
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