[Elecraft] K3 intermittent transmit power

[Phil Zminda]

My K3 -100 S/N 4385 has developed an intermittent transmit problem on CW. I operate very little SSB so can’t say if it happens on SSB. It seems that the transmit power as seen on the meter display drops to 0 on a character and then goes up to 100, even when running at 40 watts driving my amplifier, an ALS-600, modified with QSK. At first I blamed the amp and did check it out thoroughly, but see the problem even without it. I have checked all my coax connections, the amp keying keying connection, re-seated the power cable, tried both full and semi-qsk and both internal and external Winkeyer keying. I’ve seen this both with my antenna and with a dummy load. It doesn’t seem to matter which band I’m on. The problem seems to happen when the rig is first turned on and then may go away. I saw the problem when operating last night and when I tested the rig this morning on a dummy load it, re-occurred for a short while, then went away. A couple of weeks ago  ran SS CW with the K3 running QRP and didn’t notice the problem. 

Before I box up the K3 and ship it to Elecraft, I am looking for ideas of what else to check. Although I built the K3 from a kit I haven’t had it open in years. I did send it to Don, W3FPR, to update the synthesizer boards and install the 2nd receiver about a year ago, but that was the last time the rig was opened up. The problem is very recent I am not sure if having 2nd RX will require much more disassembly in order to get to any connections related to the PA. I am rather hesitant to open the rig up. My workbench space is rather limited now and I don’t feel as confident with the dis-assembly as I was when I built the K3.

Any suggestions appreciated.

Thanks,

Phil N3ZP