NorthCoast3800 graciously sent me this radio last year to try and do a failure analysis. Life happened and I didn't get to it until now.
I hooked it up to a couple speakers and my bench supply and fired it up to see if I could replicate the issue. After about 10 minutes, the volume knob started getting intermittent, so I pulled the top cover off and took a look at it.
The caps appeared to be in pretty good shape, but the solder on the ground side of the volume knob pot looked sketch. I used my heat gun and my air compressor to alternately heat and cool the pcb on the volume knob and I was able to cause/fix the issues.
Upon removal and inspection, you can see that there was a cold solder joint on that pin that had started to crack. I reflowed it, reassembled the radio, and I am not able to cause that failure anymore. I listened to it for about an hour while I cleaned the shop.
Looking online, this appears to be a pretty common problem. I suspect that is because the pin in question is going directly into the ground plane so it takes a *lot* more heat (compared to the other pins) to warm up the ground plane to get a good connection.
If anyone else has this issue with the Retrosound radios, all you need is a #2 phillips, a reasonably high power soldering iron, and 5 minutes.
