Sound issue recapped SE/30

[ESM-NL]

Recently I bought an SE/30 in a nice non-Apple carrying bag. It had sound, but nearly inaudible. A sigh of a needed recap.

I did the recap (also my firts SE/30 recap). The sound is back, but it is crackly. So I did an extra cleaning with IPA and washed away corrosion around chips. Sexond attempt did not give improvement. Sound is still crackly. The sound levels aro also not good. From lever 1 to 7, no difference at all.

One I pulled the LB out again after being on for about 5 minutes, I noticed that the LB was quite hot around the sound chip UE10. I assume that is not normal.

The tests with Snooper 2.0 were good, even after several test runs. I wonder what the problem could be.

 

[Mark_W]

Have you tried the headphone output? Is the sound clear on both channels? If so the opamp that drives the internal speaker or the speaker itself might be faulty. If only one channel is clear then one of the sony sound chips isn't working, otherwise either both sony chips or ASC at UE10 is faulty, the fact that UE10 heats up and volume is not working indicates it may have been damaged.

Your board looks mint without any visible corrosion but I'd pull UE10 off and clean any electrolyte residue underneath and check for damaged traces. Also check it's connection to data and address bus following the table in redrawn schematic diagram.

Not on SE30 but every single LC475/550/575/CC logic board I worked on has sound issues, ranging from no sound at all to low volume, noisy output, input not working.. Sound chip on these boards is surrounded by 4 leaky capacitors and every time I pull the sound chip off I can find a huge mess underneath. Already had a handful of DFAC-II chips killed by electrolytes, unfortunately these sound chips are apple customs and need to come from donor boards.