I got Siva to tune to 14MHz, AM, and then key the rig via the mic. I did this by wrapping some wire around the signal pin of the connector and sending the signal into my Anritsu MS2712 spectrum analyzer. I thought that perhaps it would be better just to see if there is a signal from the stage feeding the PA. Here is a picture of that type of connector:Īs you can see, there was little chance to make a good RF connection to the PA input from my signal generator. In fact ICOM commonly uses this kind of connector to make inter-board RF connections I have seen that kind of connector when I was refurbishing my old ICOM IC725. The rig used that kind of funny non-standard connector to connect into the RF input of the PA. This task proved to be easier said than done. Once the rig was in the shop, with calm mind, the first thing to do was to ascertain that the “no output” was actually due to the PA and not the circuitry driving the PA. It was all conventional looking circuitry, nothing special.
#Icom ic 7800 bench test manual
I downloaded the IC7800 manual and printed out the relevant sections – mainly the PA schematics. Either the PA did not fail much or not many hams could afford the rig. I spent some time searching the web on the topic of IC7800 PA failures – not much found. In the meantime, Siva “downgraded” himself to using his spare rig. Work pressures kept me from working on the repairs too soon. Such an expensive rig, pretty display, good quality knobs, good everything, but no output – not even a teeny weeny flick on the power meter.įrankie, Siva and myself helped to carry the patient downstairs to my car. The party, comprising my XYL, Frankie Zuniga 9V1FZ and myself arrived to find the IC7800 lying sadly on the table, dismantled, thick towel beneath, with the power amp module partly tilted up. The next weekend, a few of us went to his QTH. He said that it had happened before, but this time, replacing the MOSFET finals did not help. Sad news! His beloved ICOM IC7800 had died – no output. Some time back, I got a call from my good ham friend Siva 9V1SV.