Thanks to the list...

From: dave dameron <>
Date: Sat Jul 18 02:01:49 1998

Hi Doug and all,
At 05:19 PM 7/17/98 -0500, you wrote:

>> 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

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
(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.
Received on Sat Jul 18 1998 - 02:01:49 BST

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