Compaq PSU

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Hello i have a COMPAQ AP400 Workstation with propriety PSU, I have a
ATX power supply and am trying to convert the Compaq to ATX PSU
usage!! I have got the Compaq to power with the modified ATX PSU
(changed the pins around to suit the COMPAQ but it does not display or
beep! the cpu fan starts and the motherboard light lights up so i
think i am close!! It is not damaged with the compaq PSU it still
works as normal!

Re: Compaq PSU

On 12 Apr 2005 12:15:55 -0700,
(Dave McMahon) wrote:

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Since you have this proprietary PSU and we don't, it would
tend to help if you described it a bit... as much as

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Did the original fail?
It may be easier and more cost-effective to fix it.
It may be most time-effective to replace the motherboard.
Is the system even new enough, valuable enough to be worth
spending the time and $$ with power supply mods?

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You'll probably want to take a multimeter and a spreadsheet
to map out the functions of all pins, to see if (& what) the
standard ATX PSU provides that is suitable.

Some Compaq PSU supply 3.3V Standby power.  If yours does
and the board needs it, you simply can't use a stanard ATX
without more mods, additional circuitry perhaps.

IMO, since the original works you're better off dropping
this project altogether.  If you have some kind of suspicion
that the Compaq PSU doesn't have sufficient capacity, you
might look into using a secondard PSU for powering some
parts... would certainly be easier and (without more/all
info) much more certain to work.

I did once try to adapt a Compaq proprietary system to use a
standard ATX PSU.  Problem was, I didn't even have the
system, only a dead power supply.  I believe the Compaq
board needs a signal for power-good or something proprietary
but I never did confirm/prove it.  I do know that (at least
for the one I had) it was not simply a matter of matching up
voltages and the PS-ON signal pins, that didn't work.

Re: Compaq PSU

kony wrote:
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