The problem was with bypass cap C75 in the T-R switch. It had a resistance of about 1.5 ohms across it. Replacing it solved the problem. Thanks for the tips.
73 Jonathan K1RFD Don Wilhelm wrote: > Jonathan, > > It is not a "well-known problem", but I believe you are correct to > assume the problem source is in the T/R switch. I would suggest that > you check diodes D11, D12 and D14 first - or just replace them, > 1N4007s are plentiful and inexpensive. > > 73, > Don W3FPR > > Jonathan Taylor, K1RFD wrote: >> K2/100 # 2462, with all options except DSP. >> >> I've noticed just recently that when turning the Power above 10 W >> (and hearing the relays click), the receiver gain drops 20 or 30 dB. >> The receiver returns to normal sensitivity when the Power knob is >> returned to a lower setting. >> >> This must have starting happening only recently. The rig is working >> fine on transmit at all power levels. >> >> Looking at the schematic, I suspect the the first place to look will >> be the T-R switch in the KPA100, but I thought I would post to the >> list to see if this is a well-known problem. >> > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
