I have been asked to repair an HF transceiver, a Yaesu FT-990, that does not transmit. The owner had done some research and got an opinion from some repair expert that it is a failed PIN switching diode feeding the power stage. Unfortunately an exact replacement diode is not to be found, at east so far. I did remove the diode and checked it wit a DMM and it seems to pass the normal diode test of conducting in ony one direction. I am hoping that there is additional testing that will verify that it is either failed, and must be replaced, or OK, and I need to keep searching for the problem.
So what other tests can I do for the PIN diode? Besides reverse leakage and forward voltage?
So what other tests can I do for the PIN diode? Besides reverse leakage and forward voltage?