Berea, OH
Quoted from Kryose:1. The power supply circuit is putting out 5V too much voltage and overblowing the display circuit.
2. The display circuit itself has some sort of problem.
3. The main circuit board sending data to the display circuit has some sort of problem.
Have any of you seen this kind of thing before? Any idea where I should look next?
Thanks,
Kryose
Not likely to be #1, as the power is "close enough" within tolerance and used to illuminate digits which appear to be about the correct brightness, not too dim or overly bright.
It could be a problem on the MPU board or display board, but do not forget to rule out the cables by checking those first. I would want to replace the ribbon cable, and check and repin the other connectors as well, along with checking the reverse side of both boards for cracked solder joints. Rule out the easiest first. There are some common ICs prone to failure that are static sensitive on the display board, although I cannot exactly tell where to look from the type of symptom shown in the video. The easiest way to determine would be to replace the display board with a known good working board, which would tell you which board is the culprit.
