HP Pavilion a712n - It will not POST (No video, No beeps, Solid HDD Led, k/b not responding)

Hi guys/gals:
I am a comp. tech here in NY and I have a customers PC with a
rather strange issue.

Issue: PC is not booting. It will not even POST. Monitor is blank/in
stand-by. Hard Drives and Fans are all working. Hard Drive light is
solid.

The PC is a Pavilion a712n Desktop-PC. Pentium 4, IDE drives, 512mb
ddr memory, 1 cdr 1 cd drive, only 1 PCI slot occupied with a modem.
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Here are some of the PC's symtoms when first turned on:
- No Video (Monitor will not even switch off standby/light is yellow)
- No POST Beeps at all.
- All keyboard lights (num/caps/scroll) initially flash when powered
on but thereafter no keys respond, not even caps or num.
- Solid Hard Drive Light (No blinking at all, it's solid. The drive
does spin up and go through it's initital startup/self-test? process
(short series of clicking).
- Green LED on Power Supply blinks once on startup (Apparently normal
because I tested the PC with 2 other good PSUs.
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Here are some procedures I tried, all of which resulted in no change.
No Beeps, POST. No Video. K/B Not Responding. (these may not be in
order)

[Video]
- Tried other monitors.
- Tried Adding a basic PCI video card and connecting the monitor
through there.
[Power]
- Tried 2 other power supplies I had. 1 was HP, one was from a
dell (but compatible)

[Hard Drive/Other Drive]
- Tried booting without the hard drive or any IDE devices.

[Motherboard]
- Checked and Reseated all cables for m/b, IDE drives, front
connectors)
- Reseated PCI card (modem), I tried without the card as well.
- Stripped down the PC to the least components required to boot.
- Tried it without memory, Tried it with new memory.
- Tried replacing the cpu with the same exact CPU from my stock
- Ensured heat sink was properly connected and used new thermal
paste.
- Cleaned/Dusted off entire motherboard and PSU (of course with
power and clk. batt removed)
- Tried removing the motherboard from the case and running it on
non-conducting surface (no shorting)
- No Visible Motherboard/IC Problems (Carefully inspected
motherboard under worklight/magnifier to look for blown/leaking caps
or solder bridges between pins.)

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I have come to the conclusion that the motherboard is blown but I
would like your help/confirmation before I have the customer spend
$200+ for a new HP board.

I would greatly appreciate help from anyone with experiance on these
systems. Also, if indeed it's the motherboard does anyone know of a
replacement board non-oem that will fit in the HP case.

Thank you so very much guys/gals!
.

Relevant Pages

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