Re: Looking for original Apple II PSU shematics

["Michael J. Mahon" <mjmahon@aol.com>]

Nama wrote:
> Hi,
> I'm about to replace all the old and dead caps in my Apple II PSU. Does
> anyone have a schematic, as this would really help me a lot?

While I can understand your desire for a schematic, it isn't much help
if you're just planning to replace all the electrolytics.  They are all
well marked, and their physical size and temperature range are as much
an issue as their electrical parameters, and unaddressed by a schematic.

(And FWIW, in my experience the only ones likely enough to be a problem
to justify preventive replacement are the two (or four) higher voltage
electrolytics on the line side of the power supply--the ones that filter
the raw DC from the AC line rectifier.)

The real problem is that Apple contracted with several power supply
vendors for their power supplies, and each vendor felt free to revise
the circuit as long as Apple agreed that it met specs.  So there are
quite a few circuits.

The circuit for the original supply, designed by Rod Holt for the
Apple II, is in the Reference Manual (p.93).

-michael

Music synthesis for 8-bit Apple II's!
Home page:  http://members.aol.com/MJMahon/

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