I have had a B.N.O.S LPM144-10-100 solid state linear amplifier for some time. It brought it at a ham fest and it worked fine. However, when I tried to use it recently, I noticed that sometimes the amplifier would work, but other times there was no output. Due to the intermittent nature of the fault, I knew it couldn’t be the main power transistor (MRF247). The most likely cause was one of the 3 relays. There were also 5 electrolytic capacitors. I decided to change all 8 parts.
The first thing I did was cross correlate what I had with the circuit diagram (click for full size image/download).
Closeup of the 3 removed relays.
Comparing the original PCB photo with the one below, you can see the 3 replacement relays and 5 capacitors.
Below is the amplifier working! Yay!