Recent content by ThirdGear

Here's a video showing how to rewire the LS-454 so its pinout works with the PRC-25/77 audio connector. The LS-454/U connector pinout is normally configured for use with the PRC-68 radio family, and the instructions in this video show how to rewire it for use with the PRC-77...

For the PRC-77, you just can't beat the PRM-34 "God Box" for getting a quick characterization of receive sensitivity, squelch, transmit frequency, and transmit power. Here's a video demonstration of using the PRM-34 test set on a PRC-77. The RF output power measured way too high in this video...

Update: Out of three GRM-55 sets I have, only one of the MX-4622 Test Prod/Probes works between them. I am now following the pulse method to push and release the test button between cal knob adjustments as pointed out. Even so, after trying all combinations of probes and test sets, only one...

I have a couple GRM-55 test sets that don't pass self test / calibration.I can reproduce the same symptoms on two different GRM-55's using multiple different PRC-77's. Both GRM-55's are behaving similarly -- can't get a solid green on self test / cal mode. It's strange that both boxes fail...