Magic smoke!

[D Finnigan]

At last, the inevitable has transpired! On Friday I took my 1980 integer
Apple II out of its box and set it up. Saturday afternoon, after playing
Jungle Hunt, I heard the crackling noise. And saw the whisp of smoke.

This isn’t the first time a RIFA has given it up, so I acted quickly to
switch off the power. Carried the still-smoking Apple out of the room, and
opened some windows to let in fresh air. Next step is to hunt around and see
if I have an extra capacitor. I think the last machine I had to replace was
a Mac 512K. I may have ordered an extra then.

Service life in this Apple II: about 43 years. Not bad!

[phigan]

Post by D Finnigan
if I have an extra capacitor. I think the last machine I had to replace was
a Mac 512K. I may have ordered an extra then.

Are there some known people or places that one can send Apple2 and
classic Macintosh units to for re-capping?

[D Finnigan]

Post by phigan

Post by D Finnigan
if I have an extra capacitor. I think the last machine I had to replace was
a Mac 512K. I may have ordered an extra then.

Are there some known people or places that one can send Apple2 and
classic Macintosh units to for re-capping?

The Apple II isn't notorious for failing capacitors (except for this one in
the power supply!), so I don't know of any services for this kind of work.
I have heard of places for older Macintosh models, but I haven't used any of
them. There were some people selling capacitor kits for Macs too, which
could save some time as long as you did the work yourself.

[Andrew Roughan]

Post by D Finnigan

Post by phigan

Post by D Finnigan
if I have an extra capacitor. I think the last machine I had to replace was
a Mac 512K. I may have ordered an extra then.

Are there some known people or places that one can send Apple2 and
classic Macintosh units to for re-capping?

The Apple II isn't notorious for failing capacitors (except for this one in
the power supply!), so I don't know of any services for this kind of work.
I have heard of places for older Macintosh models, but I haven't used any of
them. There were some people selling capacitor kits for Macs too, which
could save some time as long as you did the work yourself.

I can think of only two classes of devices where recapping is likely to fix
1) Computer equipment (and maybe other electronics more generally) of a
certain age that was built with counterfeit electrolytic capacitors
https://en.wikipedia.org/wiki/Capacitor_plague
Apple IIs (and 68K Macs, while we're at it) predate this issue by several
years.
2) Really old devices (mostly running on vacuum tubes instead of solid-state
devices) that used wax- or plastic-covered paper capacitors in which
failure of the wax covering would cause the paper dielectric to absorb
moisture, altering its properties.

The Wikipedia article you cited acknowledges there are other causes for
capacitors to fail than counterfeit electrolyte.
One being that they can dry out over time.

I stored a IIgs keyboard in my roof space (which gets hot in summer) and it
didn’t work after several years. After a lot of troubleshooting and getting
nowhere the caps were replaced as a what-if and it now works.

Regards
Andrew

[Andrew Roughan]

BTW, “re-capping” is an artifact of 1) old vacuum tube (hot, high voltage)
equipment, 2) old and not very reliable paper-insulated or wet electrolytic
capacitors, and 3) folks not very skilled in the repair of such equipment.
The combination of these ingredients has led to an almost superstitious
tendency to “replace ‘em all”. This is almost never necessary, and often
results in needless damage.
In the case of low-voltage, solid state electronic equipment, re-capping is
certainly unnecessary and potentially damaging. (Note that power supplies
are NOT low-voltage.)

While I don’t have your experience, I have heard from others who have
extensive recapping experience, that over time, electrolytic capacitors in
equipment that is not used can degrade. To prevent degradation, the
recommendation is to use the equipment for 30mins a year to keep it
exercised.

If the equipment hasn’t been used for an extended period of time then
exercising the equipment may not result in satisfactory function.

Regards
Andrew