Computer power supply compatiility

[My father's son]

I had a Soyo computer which didn't work: All it did was turn on, light up
a
few lights on the CD-ROM, start the fan whirring and I got some very minor
clicking. Nothing whatsoever got transmitted from the computer to the
monitor which would stop the light on the monitor from flashing as if there
was nothing connected

Soyo eventually told me that the mobo was probably at fault so I replaced it
with an Asus P3V133 which I am now using with the 450 Mhz Pentium 11.

Which (when I THINK I got all the processor and voltages/bus speeds and
multiples correct) does exactly the same thing

So I am wondering if it might actually be a problem with the power supply,
a problem Soyo didn't consider.

So I bought a Compaq one for a munificent $3 at a local flea market.

Does anyone know if all ATX power supplies will work with Asus mobos? I
found out (not the hard way) that apparently all Dell ones are different and
if you plug a Dell one (which helpfully has exactly the same ATX plug) into
a non-Dell mobo, it may well fry the circuits.

Unlike the original Soyo power supply the Compaq doesnt have a power switch
on it and when I tried testing the voltages to see if they went with the
voltages cleverly set out in the ASUS manual, nothing is measured:
Apparently
unless you plug it in to place a load on it (the fan doesnt even go on when
you plug the power supply into the mains)

"Brothers and Sisters Have I None
But That Man's Father is My Father's Son"

 

[LASERandDVDfan]

Does anyone know if all ATX power supplies will work with Asus mobos?

As long as it is a standard ATX supply with the correct pinouts for the ATX
feed plug, it will work. Asus and Soyo makes stuff that conforms to the
industry standard, while Dell is far more proprietary than that. (One of the
many reasons why I opted to build my own computer rather than buy one from Dell
or Compaq.)

Whether or not it will work reliably is a different story.

Go get a new standard ATX power supply and try it out. If it doesn't work, you
can always return it to the place of purchase.

Unlike the original Soyo power supply the Compaq doesnt have a power switch
on it

And what kind of power switch are you talking about? A rocker switch on the
back of the power supply module itself or a long black cord with a locking
pushbutton switch on it?

If it's a rocker swtich on the back of the module itself, then that's likely to
be okay. Some ATX power supplies have this switch and others don't.

If it's the latter, then are you sure it's ATX? - Reinhart

 

[My father's son]

Well having bought it I kinda wanted to know if it would work rather than
having to buy another which might well be the same (but at 83 times the
price): Do you KNOW htat Compaq s are non-standard ATXs? (It IS A rocker
switch on the back of the power supply module itself)

 

[Alfred E. Neuman]

Well having bought it I kinda wanted to know if it would work rather
than having to buy another which might well be the same (but at 83
times the price): Do you KNOW htat Compaq s are non-standard ATXs?
(It IS A rocker switch on the back of the power supply module itself)

I'm fairly positive that Compaq power supplies ARE standard in regards to their
power output. The only problem I've experienced regarding Compaq power
supplies is that a standard ATX power supply will not mount correctly in a
Compaq case. Aside from the mounting problem, however, a standard ATX power
supply will power a Compaq motherboard just fine. Given that, I assume the two
are giving the same output, unless Compaq has made their motherboards
compatible with a proprietary power supply and the standard power supplies,
which I doubt.

 

[Rocky]

Well having bought it I kinda wanted to know if it would work rather than
having to buy another which might well be the same (but at 83 times the
price): Do you KNOW htat Compaq s are non-standard ATXs? (It IS A rocker
switch on the back of the power supply module itself)

If it is a true ATX power supply (monolithic plug), the power switch
on the front of the case plugs into the motherboard which sends a
power up (and then a supply good signal) to the power supply. The
rocker switch on the back turns off power to the PSU and thus to the
whole computer.

Your motherboard (Asus P3V133) has this connector in the 6th and 7th
position (from the ISA slot) of the panel connection closest to the
edge of the board.

If you want to test your PSU without a motherboard, you should connect
pin 7 to 6 ( green and black ). eg:

H
---------------------------------
|O|O|O|X|X|O|O|O|O|O|
u -- -- u u -- -- u u --
---------------------------------
|O|O|O|O|O|O|O|O|O|O|
-- u u -- u u -- -- -- u

The H is the clip for the plug, the u's mark the rounded pins on the
connector.

I have tried this and it does work.

Here is a URL for this:
http://modtown.co.uk/mt/article2.php?id=psumod

Rocky

 

[My father's son]

Thanks guys: That pretty much answers my questions although I wish someone
would have given me that advice before I changed the mobo if there IS
something wrong with the original Soyo power supply and I neednt have gone
to the bother of changing boards and figuring out all the connections, -
which arent (exactly) the same on the Asus as on the Soyo. But I dont
suppose the differences matter, - they all seem to involve connecting
peripherals such as additional fans which are already internal to the power
supply. And, yes, I WAS determined not to buy an ATX power supply which
had one of those connectors to the power switch on the front panel (so that
all I have to figure out is how to connect the 'jumper' to the pins on the
mobo)

 

[My father's son]

Uh-oh

Things not looking all that promising: none of the colours on the Compaq PS
are the same as on the Soyo PS (on which the black and green ARE the same as
on the http://modtown.co.uk/mt/article2.php?id=psumod site) On the Compaq
those two pins are black and white (which is I suppose a 50% correct rate?)

I suppose I had better both test the Soyo PS to see if the voltages match
the Asus motherboard values when jumpered (ie if it is genuinely non-
working) AND if the Compaq voltages are in fact the same despite all the
colours being different when I jumper those two same pins? (a bit unlikely?)

Then as a last resort I can cut off the plug from th eSoyo and find an ATX
with those colours in all the same positions

 

[jakdedert]

Hey, look at it this way: you already have the makings of a second computer.
Buy a new case with power supply. Use the p.s. to swap-test your old one;
then buy new drives/memory/cpu and you've got two computers...or sell the
m.b./p.s. combo as a 'barebones' kit. If your old p.s. is bad, use the new
one or replace it. A case w/p.s. doesn't cost all that much more than a
p.s. alone.

jak

 

[TCS]

Hey, look at it this way: you already have the makings of a second computer.
Buy a new case with power supply. Use the p.s. to swap-test your old one;
then buy new drives/memory/cpu and you've got two computers...or sell the
m.b./p.s. combo as a 'barebones' kit. If your old p.s. is bad, use the new
one or replace it. A case w/p.s. doesn't cost all that much more than a
p.s. alone.

The problem is that case/p.s. combinations almost invariably have a power
supply that is a complete piece of shit. They might have triacs rated for
an output of 450W, but they die all the time with less than a 200W
load.

Given the choice between a $39 case/P.S. (with an $8 power supply included)
and a $39 power supply, I'll take the latter.

 

[larrymoencurly]

if there IS something wrong with the original Soyo power supply
and I neednt have gone to the bother of changing boards and
figuring out all the connections, - which arent (exactly) the same
on the Asus as on the Soyo.

Soyo PSUs are made by Key Mouse, www.kmepc.com, and aren't the very
worst you can get, although mine caused a lot of radio inteference
because it didn't contain a line filter, contrary to what the website
said. My 300W managed 300W and also met its 190W combined +3.3V and
+5V rating, at least for ten minutes (limit of my test).

To turn on a PSU without a mobo, connect its pin 14 (green wire, Power
On) to a black wire, like pin 13 or 15 next to it. Some PSUs also
need a load of 20 ohms or less (use 10 watt resistor -- could get hot
otherwise) between red and black wires for the +5V.

Compaq PSUs are supposed to be really good and made by Newton or
somebody.

 

[My father's son]

Yes, I was able to test the Soyo PS with this method but cannot interpret
the results: The PS DOES seem able to give out 3.3 volts, 5 volts and 12
volts. But some (one?) of the pins which should give out 12 volts only
gives out 10 and a 5 volt one only gives out 3 volts.

Does this mean that the power supply has failed or might it be OK when under
load? Put another way, when power supplies go bad, do they TEND to go out
in toto or can this type of behaviour be indicative of a PS which has in
practice failed? The COmpaq has completely different pin colours and
voltages despite having the same type of plug going into the MoBo.

Otherwise I wish I could make another computer with a lousy 233 Pentium 1
Dimension I have here which works, a good Soyo Pentium 11 MoBo, numerous
good hard drives and only a need for a Pentium 11 processor. But as it is,
none of the parts work together in the first computer (not to mention any
potential second one)

 

[larrymoencurly]

Yes, I was able to test the Soyo PS with this method but cannot interpret
the results: The PS DOES seem able to give out 3.3 volts, 5 volts and 12
volts. But some (one?) of the pins which should give out 12 volts only
gives out 10 and a 5 volt one only gives out 3 volts.

I've found that the voltages will often be out of tolerance when a PSU
is tested without the mobo because some PSUs need rails to be loaded
with at least 1 amp, and I have a PSU that needs far more than that
and when loaded with just a 466 MHz Celeron the +12V rail will be so
low that the HD won't even spin. The Key Mouse website once listed a
minimum current of 5A for the +5V rail of one of its PSUs.

It's possible that the +5V wire that measures at only +3V is actually
a signal
line, like the Power-On signal (grey on standard ATX PSUs). One way
to find out is by connecting it to a known good +5V wire through a
1K-2K resistor (do NOT connect it directly to +5V!!!), and if it
increases to +5V then you know it's a signal output rather than a
voltage supply line.

Have you tried www.support.compaq.com to find the Compaq's pin
specifications?
Unfortunately it doesn't seem to be nearly as easy to use as Gateway's
online help.

 

[My father's son]

The Compaq really isnt in contention at the moment

Its purchase was probably a misake and it was probably intended for some old
workstation but coincidentally has the same plug to a motherbaord.

I think you are right about the PS There probably isnt a lot wrong
with it as it CAN give the correct voltages so i assume it can give them
under proper circumstnaces and through the proper pinouts

But I have now excluded the mobo, the memory, the PS, the processor and the
video card

This is getting really baffling and the guys at the ASUS boards couldn't
asssit in telling me what jumper settings I might have got wrong. But it
also raises the possiblity that the SOyo mobo wasnt broken in any way and it
didnt have any particualr jumper settings

Baffled

 

[jakdedert]

Start at the beginning: mobo and p.s. hooked up with only processor
installed. Listen for beeps. If you get them, add in memory--beeps again,
add video card...and so on until the process fails. That's where your
problem lies.

jak

 

[My father's son]

Unforunately it isnt that easy: I tried that and dont get any beeps at all
under any circumstances. (But I cant figure out if that is because the
contact to the speaker is loose or not)

 

[123.bam]

Start at the beginning: mobo and p.s. hooked up with only processor
installed. Listen for beeps. If you get them, add in memory--beeps again,
add video card...and so on until the process fails. That's where your
problem lies.

jak

you forgot to mention to hook up the small speaker to the mobo, otherwise you
may not hear a diagnostic beep sequence