21 Mar
2015
21 Mar
'15
2 a.m.
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
21 Mar
21 Mar
11:04 a.m.
On 03/21/2015 01:00 AM, Marc Verdiell wrote:
A classic case of Mac SE leaking electrolytic caps.
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.
None of my Apple hardware seems to be affected (or at least, wasn't the
last time I had cases open), but I hear enough reports of it that it seems
to be quite common.
If it was a problem with a specific machine I'd think it was a design issue
- heat build-up, maybe, or working at close to voltage limit, but it seems
to hit several different products. 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?
cheers
Jules
3:25 p.m.
On Sat, Mar 21, 2015 at 9:04 AM, Jules Richardson
<jules.richardson99 at gmail.com> 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.
10:15 p.m.
On Sat, Mar 21, 2015 at 11:04 AM, Jules Richardson
<jules.richardson99 at gmail.com> wrote:
On 03/21/2015 01:00 AM, Marc Verdiell wrote:
I have a dead Amiga 4000 with leaky caps on the CPU board :-(
http://amiga.serveftp.net/A3640_capacitor.html
-ethan
A classic case of Mac SE leaking electrolytic
caps.
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
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