[IWE] Power Supply question

[D. Scott Katzer]

Hi Jay,

Jay Burns IV wrote:
> Greetings, wizards-
> 
> I have a friend who has a Compaq thing of some kind.  It's older and it 
> steadfastly refuses to tell anyone what model it is  All it says on the 
> front is"Compaq"...no "Deskpro" or "Presario" or "Evo" or anything like 
> that.  Nothing on the roughly half dozen stickers with innumerable 
> barcodes o the back of it, either.  Its all black, in a what they call 
> their Compact Workstation Tower (CWT) case.  Has both a CD and DVD 
> reader/writer on it, and a (gasp) 5-1/2" floppy drive, too!
> 
> And it doesn't work.
> 
> At least, not for very log...You power it up, and it runs for about a 
> minute, just enough to get XP-Home to display the login screen (she has 
> logins enabled, for reasons that I will never know, and am probably 
> better not knowing...).  Then there appears to be an abrupt loss of 
> power...but not all power.  The CPU fan stops running, the video card 
> halts (driving the monitor to black).  But the LEDs on the network port 
> (it has integrated networking) continue to flicker, and the power supply 
> fan continues to run.

This doesn't sound like a power supply problem to me.  It sounds like 
the CPU is shutting down - maybe due to overheating?  But maybe the +12V 
and +5V rails of the supply are Ok, but the +3.3V has died.

> I suspect there is a power supply problem.  I haven't check ed the power 
> leads yet tot he MB...I'm going to do that later tonight.

An alternative is to get a utility that reads the power supply voltages 
in Windows, but they're usually chipset-specific.  SpeedFan may work 
though - http://www.almico.com/sfscreenshots.php  If you can keep it 
running long enough, then it might tell you the voltages without needing 
a meter, etc.

> However, I 
> had it open on got the model number off the power supply.  It's a 
> HP-P251GF3.  Finding a new one of these isn't easy, and the way too 
> expensive (between US$200 and 250; you can just about replace the entire 
> machine for that).  In poking around the interwebs, I found that HiPro 
> makes a similar supply, the 244166-001.  Much of the literature states 
> that this power supply will "just drop in " to a number of Compaq PCs, 
> mostly Presarios.  That's great, except that I may not have a Presario...

As long as the power connectors are the same (20 pins vs 24 pins vs 20+4 
pins) and the power rating is the same for the +3.3V, +5V, +12V, -12V 
rails, and the layout is the same (fan location, power cord location, 
switch location), then it really shouldn't matter.

> So the question I'm asking o you is, does anyone know if a HiPro 
> 244166-001 is a direct replacement forthe massively overpriced 
> HP_P251GF3?  I'm pretty sure they are compatible from a plug 
> perspective...but I'm not sure the mounting holes and al the physical 
> interfaces will line up (you know how Compaq is regarding puting 
> standard things in non-standard places on teir boxes...simply to insure 
> that you'll have to buy their overpriced crap when a part fails).
> 
> Any info would be appreciated.

A guy at work was in a similar situation.  He had a Presario that had a 
dead PS and he wanted to resurrect it.  I think I became convinced that 
there was no difference between a $20 NewEgg supply and the $200 exact 
replacement he found somewhere.  But he knew the machine number, etc.  I 
think he spent the extra "to be sure", but I wouldn't have.

I would take a look at this 300W HiPro (out of stock, unfortunately)
http://www.newegg.com/Product/ProductReview.aspx?Item=N82E16817174026

and this
http://www.newegg.com/Product/Product.aspx?Item=N82E16817338005

and this
http://www.atxpowersupplies.com/250-Watt-Power-Supply-Compaq-244166-001.php

and see if there's anything obviously different between them.

HTH a bit.  Good luck!

Cheers,
Scott.
> 
> thanx-
> jb4