From what you write it sounds like the display indicates the scanner is doing what it should. In other words, it boots and runs. Makes me wonder about your antenna (connection).
OP, do you have an extra antenna to test?
I was nearby one of the SRRCS Countywide Simulcast sites, and on a whim, I took off my antenna and the signal was strong enough that I was able to receive audio with the antenna off. This might be a fast and easy way to determine if the unit is experiencing the Cold Solder Joint issue or a defective antenna.