17 Jul
1998
17 Jul
'98
7:01 p.m.
Hi Doug and all,
At 05:19 PM 7/17/98 -0500, you wrote:
Pins 1-50 on front, 51-100 on rear.
Pin 1, 51 +8 Volts. Leftmost from the front, front and back. Unregulated
(just filtered rectified DC from the power transformer) for the +5 volt
regulators.
(Usually very easy to trace or test)
Pin 2, +16 Volts, unregulated.
Pin 52, -16 Volts, unregulated.
In my system I put fuses in these lines. Make sure the filter capacitors
have bleeder resistors attached, so they will discharge without a load.
Otherwise you might have problems when plugging in a card later :-(.
Pin 50, 100 Ground.
There were other ground lines on later cards, which you may have to check
for when you start to mix cards,
such as pins 20, 70, which were Unprotect, Protect in the early S-100 systems.
-Dave
5) Check the
+8, +/-16, and GND pins on the bus connectors before
powering up, make sure nothing's shorted.
I found the power supply wasn't very well regulated, so you might see
higher voltages without a load. Which pins on the S-100 bus correspond to
those volatages? I just checked the mobo terminals, one of which was
unlabeled.