pce duo sound repair form HELL!

[crans]

So I picked up a broken duo that has broken audio and a prior person with zero skill or eye sight has mucked it all to hell fixing cap's .

Many caps backwards some popped and originals still in place with obvious corrosion all over the place and some chips shorted.

First thing I did was remove all the crap work and original cap's. Cleaned all pads tined and gave it a sonic wash.

Recapped and got the audio back to 10%. 4558 is missing voltage so checked and some legs where corroded off the chip, replaced it. The M51131L had some bridging top side, removed and cleaned and replaced. After this the audio has gone from 10% back to original zero.

Now I have no audio and seems the 4558 is getting weak power but none of the voltage it should. Jumped some via's to pads with lifted traces.

With all that knowledge I have found the rail that provides 8v is low at 1v. I would guess some diode or transistor is toast from reversed caps around the large transistors (they are working with correct voltage  5v/8v)

Prior to rebuilding the board 100%. Any known components I could check?

Thank you for looking.

[crans]

seems Q603 was not passing the 8v.  Chip tunes are back now

[NightWolve]

Cool you saved it! Don't understand how someone learned enough about these consoles needing full capacitor replacement and basic soldering technique but not enough to mind the polarity of an electrolytic cap...

[crans]

im going with blind tech or drunk or blind drunk idk.  Solder splash was all over and from the first sight of the board i knew it was not going to be a walk in the park fix.

[thesteve]

the problems are nothing new to us here
if you get stumped ask, but it sounds like you have a decent grasp of how it works

[ApolloBoy]

Don't understand how someone learned enough about these consoles needing full capacitor replacement and basic soldering technique but not enough to mind the polarity of an electrolytic cap...

Or had the decency to recap the entire system when it's well-known that all the caps in the Duo go bad...

[Necromancer]

Congrats on getting her fixed properly. 

Whoever abused that poor Duo should be beaten.  Severely.