Mac SE/30 making zipping and buzzing noises

[Marc Verdiell]

A classic case of Mac SE leaking electrolytic caps. Soon your sound will
disappear completely. Then your Mac SE/30 won't even boot. You can confirm
looking for shiny leaks traces around the caps. Very easy to take care of.
Replace all of them, as they will all go bad. But there aren't many of them,
I think I counted just 11. Most of them are of the 10 uF variety if I
remember. Surface mount with leads hidden underneath the caps, a bit
annoying to remove, but you can pretty much break them off the board
carefully. The leads should break off at the cap and stay attached on the
board. Then desolder the lead remnants and clean off the old solder with
copper wick until you get pristine pads. Clean any spilled electrolyte under
the caps thoroughly. Replace them with regular 10 uF ones - or whatever
value is needed. I used standard axial through holes ones, just soldered the
bent leads on the traces. It's even written on the board where the + go!
Thanks Steve Jobs. If I could attach pictures of the before and after, I
would... I can send them to you off line if you want. Actually I see your
email, I will.

Marc

On 20/03/2015 6:39 PM, <dave at 661.org> wrote:

> I'm gradually restoring a Mac SE/30.  Today I got a new PRAM battery 
> and installed it.  There was no battery leakage, so I'm good there.  
> The machine seems to run just fine.  The big problem now is that even 
> though nothing should be emitted from the speaker, I'm getting zips, 
> buzzes, and burbles from it depending on what the computer is doing at 
> the time.  I'm quite sure the the sound circuitry is somehow picking 
> up RF noise from the system bus.  What does this symptom indicate?  
> Should I recap the whole machine?
>
> David Griffith
> dave at 661.org