Hi! I finally got around to solder together my Juma RX-1 kit I'd purchased a couple years before. Everything connected, I noticed that my 12 volt power source was broken, so tried to boot the radio up with a 9 volt battery. And it worked: I got the greeting CW on the speaker and welcome message followed by frequence & S meter screen on the LCD. Frequency selection worked, too - or so I assume; the number on screen changed. I didn't have an antenna connected so I just heard noise. I disconnected the battery and left the kit on my desk, planning to attach it to a dipole the next day.
However, when I turned the receiver on the next day, the display remained dead, and I could hear no CW from the speaker. I could hear the static, though, and turning the pot changed the loudness. Dumbfounded, I checked the battery voltage - same as yesterday. I found a battery holder for eight AA batteries (I only had NiMH batteries, so got only ~10 volts, but that should be enough, shouldn't it). However, same result: just noise on the speaker, nothing on display, no CW heard.
I checked if there was some misplaced conductive material somewhere on the circuit boards, blown in - couldn't find anything. All the soldered connections appeared good, including connections between the microcontroller and LCD. And checked by multimeter, they were good. Also, there was 5 volts after the DDS card regulator in all the places there should be, including the LCD board and the correct leg of the microcontroller.
So now I'm a bit at a loss. I can hear noise on the speaker, I'm guessing the RX card mostly works. But the microcontroller on the DDS card doesn't seem to boot up. It did boot the day before, and I turned it on and off multiple times, then spent the day on my desk, battery disconnected, nobody touched it, come next morning - dead. Any ideas what to try next?