Re: Apple IIgs powersupply

[dempson@atlantis.actrix.gen.nz (David Empson)]

Further to my previous posting on this subject: I have located the
110V IIgs power supply, and now have them both open for comparison.

> Well, looking at the label on the bottom of my ROM 1's power supply:
> it is made Astec, in Malaysia.  It says that the input is 230V AC at
> 63 watts, 50 or 60 Hz.  No mention of switching options or other
> voltages.

The 110V one has exactly the same label, except that it says 110V
instead of 230V.

Inside the power supply, the circuit boards are identical, but there
are several major differences in the installed set of components in
the primary stage.

The 110V power supply is missing the fuse (the holder is empty - I
suspect it was removed because it had blown; I've never tried to use
this power supply).

Obvious differences: the 110V supply is missing capacitor C1, has a
much smaller capacitor at C3, has a capacitor at C25 instead of a
resistor (R48), has a different capacitor at C5 (220 microfarads at
200V, instead of 100 microfarads at 400V), has a different resistor at
R3 and R8, has a jumper at J4 in place of R45, and possibly has a
different power transistor at Q2.  Capacitor C8 is not installed in
the 230V version, and there is a different resistor value near the big
transformer.

There are a few differences in the wire jumpers on the board: J3 is
connected in the 230V supply, missing in the 110V one.  Inductors L9
and L10 are replaced by jumpers J1 and J2.

The transformers look pretty similar.  The small transformer (L2B)
have the same part numbers, but the large one has a different number.

The 110V supply has a couple of plastic shielded inductors (I think) on
the power lines (they are coated with translucent glue, which makes it
hard to see what they are).