No sound from Color Classic

[EvieSigma]

My Color Classic (upgraded with a 550 board) no longer bongs when booted up. I haven't recapped the 550 board so could it be caps that are the cause?

 

[BadGoldEagle]

Yes.

http://www.maccaps.com/MacCaps/Capacitor_Reference/Entries/1994/2/2_Macintosh_LC_550.html

 

[EvieSigma]

On the one hand I'm glad it's not some weirdness on the analog board, on the other hand it's frustrating to have to recap something...I only just learned how to solder period this weekend!

 

[EvieSigma]

Giving the motherboard a really good clean with isopropyl alcohol (including the edge connector) restored the bong! I didn't notice any tell-tale wet spots from leaking caps before cleaning though.

 

[BadGoldEagle]

Yes but that will be temporary. You just fixed some of the shorting traces. It will happen again. And again, and again. 

Only a proper recap: bath or really good scrub and new capacitors/solder can fix it. Then it’ll be good for another 20 years hopefully.

 

[EvieSigma]

I just find it strange that there were no wet spots from cap goo on the dusty board. Some pads that were less shiny than others, sure, but you'd think if my sound had gone completely out there would be utter cap carnage.

 

[Zippy Zapp]

It is often hard to tell because the dust can stick to the fluid and it just looks like dust.  But if you were to hold it to the light at a certain angle you can sometimes see it but not always.  Dull or crusty solder pads/component legs are a dead giveaway.  

 

[eraser]

If you keep running this Mac without recapping it the damage will be permanent.  There is zero doubt the caps have leaked and they are now no longer providing the proper capacitance.  You are putting all of your ICs at risk by using it in this state.  If the analog board/PSU hasn't been recapped it needs it too.