Mac SE/30 making zipping and buzzing noises

Eric Smith spacewar at
Sat Mar 21 14:25:12 CDT 2015

On Sat, Mar 21, 2015 at 9:04 AM, Jules Richardson
<jules.richardson99 at> wrote:
> Does anyone know why Apple machines of that era (including GSes and even
> late IIe machines) seem to have a reputation for this? I've never seen it in
> systems from other manufacturers - obviously there are cases of caps going
> high-ESR or with bulging (and sometimes even split) tops, but I've never
> seen one puke its guts all over the PCB.

In the Apple II series, I've only seen the X2 and Y2 safety-rated
capacitors in the power supply fail, which can be somewhat
spectacular, and that happens in non-Apple equipment of that age as
well. I think that's just expected as the capacitor gets way beyond
its expected operating life.

For the Macintosh, Plus, SE, etc., the electrolytics, and pretty much
all of the other components of the analog board are subject to heat
substantially beyond their rated specifications. Mr. Jobs insisted on
having no fan, and only vent holes, and it is inadequate.

> My guess is that Apple just used a particular supplier that few other makers did, and those caps happen to be prone to age-related failure?

I don't think so.

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