I had a similar problem.
Locate the 3 Driver Fets that use the bottom cover as a Heat Sink (see Assembly Manual).
I would do this test on 80 Meters. In the SSB or AM mode Key the PTT or TX and FEEL
The bottom cover to see if the Driver FETS Gets HOT. If Hot they are most likely shorted.
I think I found this test on U-TUBE. If none of the Driver Fets gets Hot, then I would look
At the Output FETS. If you are Comfortable Working on the Radio, you can take the bottom
Cover off and remove the FETs from the board and test them with a Multi-meter.
Hope that helps…….. Ray WA6VAB.
Last week I noticed that my K3 has no TX output on 6m band.
I run Transmitter gain adjustment procedure on all bands.
I noticed that 160m and 10-6m has problems and can not finish properly the adjustment procedure.
Here are my results using a dummy load:
Transmitter Gain adjustment
Measures RX: 14.9V, 1.19A, PA 24C, FP 20C
Band, Reaching Power, SWR, Voltage, Current, Error
160m, 2W, 1.2-1, 14.7V, 2.78A, ERR TXG
80m, 5W, 1.0-1, 14.6V, 3.27A
60m, 5W, 1.0-1, 14.6V, 3.33A
40m, 5W, 1.1-1, 14.6V, 3.30A
30m, 5W, 1.0-1, 14.6V, 3.38A
20m, 5W, 1.0-1, 14.6V, 3.19A
17m, 5W, 1.0-1, 14.6V, 3.19A
15m, 5W, 1.0-1, 14.6V, 3.25A
12m, 5W, 1.0-1, 14.6V, 3.24A
10m, 5W, 1.0-1, 14.6V, 3.35A, ERR TXG
6m, 0.1W, --, 14.8V, 2.19A.
For the measurements I replaced the KAT with the antenna interface card, so the problem is not in KAT.
I guess that possible components that can cause such problems are LPA and maybe the SWR Bridge.
What components in the LPA or in SWR bridge can cause such?
Has anybody had similar problems?
73 de Jarmo, OH8KVA