Mar 212018
 

Got from Portugal another Dogyuun PCB (after the one of some months ago), this was declared as ‘dead’ by the owner :

And it was so.All I got was a steady black screen, no activity on board, no clock on 68000 main CPU.I checked voltages on edge connector and there was no +5V  so the board was actually not powered :

A quick inspection revealed corrosion on edge connector:

Once cleaned it the board booted and played fine but sound samples were muffled and some static noise was present :

Some sign of electrolytic capacitor leaking was present on sound section :

I fired up my ESR meter and started measuring capacitors.A couple of them, the 220uF 16V @C7 and the 10uF 16V @C9, gave no reading so out of range of my meter (0-99 Ohm)

I replaced them, this restored clear sound.No other issue were found so board 100% fixed.

 Posted by at 5:19 pm