Allen Hundley <allenphundley@...>
I was only interested in this hobby as a way to communicate with Baofengs during hunting, etc. Well I had a few spare dollars and ordered a uBitX v4 off eBay.
Last night I wired it all up and listened...didn't have an antenna just a piece of wire. It worked all right. I tried to turn up the volume to listen to a feint signal, turned it back down...all was well.
Then I went to go use it this morning and it instantaneously started transmitting. The MOSFETS in the back got hot rapidly and I turned them off.
Well, I noticed that if I removed the harness on the display/arduino that it would work again. I then isolated that behavior to a 4.7k resistor that is explicitly required in the instructions to prevent this exact phenomenon from happening. I tested continuity and resistance...it was fine. I unsoldered it and the radio appeared to work. I replaced the resistor. Same problem.
I left it unsoldered and attempted to listen. It was then that I noticed the rotary encoder was behaving strangely. The arduino clearly was recognizing something, but something was messing with the signal.
Before I break out the oscilloscope, I was wondering if someone could point me in the right direction. Thanks!