Power supply question

From: ajp166 <ajp166_at_bellatlantic.net>
Date: Sat May 12 21:48:39 2001

From: Ken Seefried <ken_at_seefried.com>


>Forgive me if this is a silly question; it never got covered in my
digital
>electronics classes :-).
>
>Is a modern switching power supply a suitable replacement for an ancient
>(and dead) linear power supply in a classic computer (PDP-11, FWIW)?


First switch mode vs linear only covers HOW the regulation is obtained in
a power supply unit.

Most of the DEC PDP-11s had switch mode supplies especially the Qbus
PDP-11s though many of the later Unibus systems did as well.

The problem using a PC supply is that DEC supplies provide DCok and
BeventL (line time clock) to name a few signals plus the +12 and -12
power may exceed most PC PSUs. the later is something for a case
by case study.

I have used a 200W PC supply (it was handy) to run a 12 slot H9281-AC
with 10 cards in it. I had to supply DCok and Bevent-L, it was otherwise
ok.

Allison
Received on Sat May 12 2001 - 21:48:39 BST