At 10:16 PM 9/18/98 -0700, it was written:
>At 10:19 PM 9/18/98 -0500, Wirehead wrote:
>>
>>> I measured the voltages across a power connector and got 9.4V, +17.56 and
>>> -17.86. A little high but I attribute that to a lack of a load.
>>
>>Actually, I think most power supplies in S100 mainframes tend to run a
>>bit high so they can handle the load and because it doesn't matter since
>>each board has it's own regulators anyway.
>>
>>Anthony Clifton - Wirehead
>>
>On some (static memory and other) cards the linear regulators get quite hot
>with the high input voltages. Doesn't help here that the 117 Volts is
>sometimes 122 Volts or higher. For these systems I run them with a 12V
>transformer wired as a 120 to 108V step down (buck) autotransformer. I first
>tried with a variac to see how low the voltage can go, usually below 100V
>with supplies with a lot of "margin", such as many of those open frame
>linear supplies.
A note in defence of the much maligned Altair while on this subject...
May I point out the the Altair 'B' series machines were one of the first to
provide a main transformer with a multi-tap primary to allow for adjusting
for varying loads and local AC supply.
-jim
---
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The Computer Garage - http://www.rdrop.com/~jimw
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Received on Sat Sep 19 1998 - 00:31:33 BST