Compaq power supply failure

[Dan]

The box I use at home is a Pentium II Compaq full tower (built like a
tank and weighs like one).
Outdated as it is, it runs fine with Windows 2000 pro SP4, with all
programs such as Nero 6, Firefox 2 etc.

It recently began this problem of every now and then not turning on
when the ON button is pressed. However, sometimes it would turn on
several minutes afterwards. I'd been suspecting something wrong with
power supply all along.

A couple of days ago it turned on after a long delay (one hour or so
after I'd pushed the ON button. But no memory check, no booting,
nothing. The monitor was not receiving any signal. Plus, the POWER ON
indicator was blinking (2 seconds on - 2 seconds off -2 seconds on
etc).
I turned it off. Now whenever I turn it on, it comes on (fans running,
LEDs on but that's all: no booting. It seems power reaches the devices
(I tried ejecting CD, it responds fine).

Could it means I've lost the power supply? strange, considering that
the system powers up convincingly, with all fans (Processor and Power
Supply) running and LEDs lighting up.

Anyone came across this? please assist.

 

[Jan Alter]

The box I use at home is a Pentium II Compaq full tower (built like a
tank and weighs like one).
Outdated as it is, it runs fine with Windows 2000 pro SP4, with all
programs such as Nero 6, Firefox 2 etc.

It recently began this problem of every now and then not turning on
when the ON button is pressed. However, sometimes it would turn on
several minutes afterwards. I'd been suspecting something wrong with
power supply all along.

A couple of days ago it turned on after a long delay (one hour or so
after I'd pushed the ON button. But no memory check, no booting,
nothing. The monitor was not receiving any signal. Plus, the POWER ON
indicator was blinking (2 seconds on - 2 seconds off -2 seconds on
etc).
I turned it off. Now whenever I turn it on, it comes on (fans running,
LEDs on but that's all: no booting. It seems power reaches the devices
(I tried ejecting CD, it responds fine).

Could it means I've lost the power supply? strange, considering that
the system powers up convincingly, with all fans (Processor and Power
Supply) running and LEDs lighting up.

Anyone came across this? please assist.

I'd agree with you that it's the PS. The PS supplies different voltages
through the mb; and although you may have minimum necessary voltage and
current to peripherals the necessary voltage to parts on the mb may be
insufficient. The way to be sure of this is to use a voltmeter and check the
voltages from the PS while the PS is under a load; perhaps just attaching it
to an old hard drive while reading those voltages that you should have.
Most likely what has been happening is that there is a leaky capaciter
not charging for necessary voltage. The more you tried it in its early
stages the more the cap heated and expanded to stop the leak and build the
voltage, but as time continued the leak just kept getting bigger and at this
point it's leaking more than the heat variable can hold the electrolyte to
supply the voltage.
See if you can substitute another PS before you immediately run out to
replace yours. It's possible that that the one Compaq supplied is
propriatory and a generic one will not have the correct connectors. If
that's the case it becomes questionable if the price it will cost for the
replacement is worth it to keep your system running for another year before
you decide to replace the whole rig.

 

[limeylew]

The box I use at home is a Pentium II Compaq full tower (built like a
tank and weighs like one).
Outdated as it is, it runs fine with Windows 2000 pro SP4, with all
programs such as Nero 6, Firefox 2 etc.

It recently began this problem of every now and then not turning on
when the ON button is pressed. However, sometimes it would turn on
several minutes afterwards. I'd been suspecting something wrong with
power supply all along.

A couple of days ago it turned on after a long delay (one hour or so
after I'd pushed the ON button. But no memory check, no booting,
nothing. The monitor was not receiving any signal. Plus, the POWER ON
indicator was blinking (2 seconds on - 2 seconds off -2 seconds on
etc).
I turned it off. Now whenever I turn it on, it comes on (fans running,
LEDs on but that's all: no booting. It seems power reaches the devices
(I tried ejecting CD, it responds fine).

Could it means I've lost the power supply? strange, considering that
the system powers up convincingly, with all fans (Processor and Power
Supply) running and LEDs lighting up.

Anyone came across this? please assist.

Obviously I don't know where you live but here, in TX, I often find
'garage sale' computers in the $10.00 - $20.00 price range and have
actually had a situation recently where the box I bought had a dead
power supply and I replaced it with a power supply from a box that had
been gutted, except for the PS and left out for the trash man.

You need to check the plug-in to the motherboard. I don't think there
are many different types of plug, so its not rocket science.

Then again, are new one is not a great expense.

 

[km]

Obviously I don't know where you live but here, in TX, I often find
'garage sale' computers in the $10.00 - $20.00 price range and have
actually had a situation recently where the box I bought had a dead
power supply and I replaced it with a power supply from a box that had
been gutted, except for the PS and left out for the trash man.

You need to check the plug-in to the motherboard. I don't think there
are many different types of plug, so its not rocket science.

Then again, are new one is not a great expense.

The point made about the propriaty power supply could be relevant in
that it is not the connectors physical look that is different but the
way that it is wired.

km

 

[km]

The point made about the propriaty power supply could be relevant in
that it is not the connectors physical look that is different but the
way that it is wired.

km

where's that spellchecker gone?

km

 

[kony]

The point made about the propriaty power supply could be relevant in
that it is not the connectors physical look that is different but the
way that it is wired.

I can't claim to have seen ALL Compaqs from that era, but in
general they did use standard ATX PSU except for a few
smaller form factor units that had what looked more like a
retrofitted AT pair of (single row) connectors.

I'd suspect power supply, motherboard battery, motherboard
capacitors. Clearing CMOS is the first try.

 

[Dan]

The machine doesn't get anywhere near executing cmos. No signal ever
goes to the display, no beep codes, nothing. Only that power on LED
lights (first day it was blinking, thereafter it lights continuously).
The IDE light also comes on when the ON button is pushed, then goes off
after 10 seconds or so. The PSU fan is running.

I visited HP web, but the info given there about PSU fix is not helpful
at all (such as telling me to go try another wall outlet ha-ha)

Motherboard power supply looks like ATX: I haven't yanked it out to
count the pins, but I suspect it wouldn't be same as generic ATX. Plus
wiring could be different as someone has noted before.

The power supply is huge, with enough 5/12 rails to power 6 or so ide
devices, although I've been using just one HD and one CDRW--and one
dormant floppy drive. I therefore don't think it is the case of
overload.

 

[kony]

The machine doesn't get anywhere near executing cmos. No signal ever
goes to the display, no beep codes, nothing. Only that power on LED
lights (first day it was blinking, thereafter it lights continuously).
The IDE light also comes on when the ON button is pushed, then goes off
after 10 seconds or so. The PSU fan is running.

I visited HP web, but the info given there about PSU fix is not helpful
at all (such as telling me to go try another wall outlet ha-ha)

Motherboard power supply looks like ATX: I haven't yanked it out to
count the pins, but I suspect it wouldn't be same as generic ATX. Plus
wiring could be different as someone has noted before.

Why suspect it wouldn't be the same? If it looks like ATX,
odds are it is. Dell was the OEM notorious for using an ATX
connector with non-ATX pinout, not HP or Compaq.

That doesn't necessarily mean it has a standard ATX case
(dimensions), some older HP were a shorter form factor with
the same rear face dimensions but not as long. Either way,
measuring the case dimensions and noting the connector wire
colors should indicate what is needed to replace it (if
that's the problem).

The power supply is huge,

Define huge.

with enough 5/12 rails to power 6 or so ide
devices, although I've been using just one HD and one CDRW--and one
dormant floppy drive. I therefore don't think it is the case of
overload.

# of plugs doesn't necesarily mean anything, and at this
point it's not a matter of initial capacity, it's a matter
of whether the part has failed. Everything fails,
eventually... now it's just a matter of figuring out what
has gone wrong.