User`s guide

Blown Electrolytic Capacitor(s)
On the end of the circuit board near the Switch are some relatively large
electrolytic capacitors (typically these are tubular aluminum things with
shrink-wrapped grey or light-green covers on which there are markings). Usually,
they are the same size and have the same uF value and Voltage rating. One (or
more) of these may be obviously blown or may just show some slime near the base.
If you find something like this, the suspect capacitor should be replaced
by one of the same (or slightly larger) uF value with the same (or larger)
Voltage rating. Size and shape are, also, important in order to get a good fit.
When removing the bad cap, be sure to mark the "+" side on the board-- use
the markings on the cap's cover to identify the "+" side. Install the
replacement cap with its "+" lead in the marked hole.
Note: Also see the fix in the next Q&A and the C7 fix discussion in Q&A 012.
Messed-up or 'Dirty' Adjustment
The power supply may have a mini-potentiometer mounted on the circuit board
for fine-tuning voltage output. Usually, it will be somewhere near the end
opposite the Switch and will have a slotted plastic 'knob'.
If there is such an adjustment, mark its current position and, then, turn
it back and forth. (If you have some Radio Shack, etc. 'Circuit Cleaner', into
the mini-pot first is a good idea.)
Set the adjustment a bit to one side of the original setting and plug in
the power supply. If it now seems to work the problem was a 'dirty' voltage
adjustment control.
Check the voltage on the +5V line with a meter and adjust it to 5 Volts.
(Note: _no_ output due to a dirty adjustment control seems unlikely. Incorrect
output is more probable; and, this could cause a IIe to not work.)
Beyond the above, you are, most likely, looking at a bombed electrolytic
capacitor which is not obviously bad, a blown resistor (which may be easier to
spot), or a blown main power transistor (the big silvery thing mounted on a
heatsink). Unless you enjoy more involved electronic testing and repair work,
your best course is, probably, to get a replacement power supply.
______________________________
From: Mark Cummings
011- Some of our classroom IIe's don't work at all. There
is no beep and nothing on the monitor. Do the power
supplies need to be replaced?
Maybe not. My experience with a couple Australian Platinum //e's indicates
that you may be able to repair the power supplies.