ASRock P4VT8+ freeze at POST

Hot-swapping and Boot-Block flash & Boot block flash and floppy support
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chox_nox
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Joined: Fri Dec 09, 2005 10:28 pm

Hi all,

I have one really strange problem with mobo I got from friend.
It's ASRock P4VT8+ (FSB800, DDR400, SATA, AGP8x, supporting Northwood/Willamette/Prescott ... )

My problem is:
1. I put a Celly @ 2.4 GHz, 256 MB memory, PCI video card, P4 PSU compatible (450W, with ATX12V connector although there is no this type connector on the mobo :S) and turned it ON. There was nothing on the screen. After few seconds I smellt a burning silicon. Immediately, I turned it off. The burning component was somewhere between ATX connector, mem slots and CPU slot. There are only 3 coils, 5 capacitors and 4 quadratic elements with 3 pins (middle pin is in the air, not connected to the mobo) marked of the PCB as Q#. I touched all those elements and they were as hot as hell.
2. After hour or two, I turned again mobo. But this time I was using older PSU (235W) and as soon as I turned it on, a big blue flash got out of the PSU, I heard a loud explosion inside PSU and a grey smoke got out). I turned off mobo immediately. I opened PSU and I saw that fuse was the one that exploded.
3. After this incident, I took the measuring instrument and checked conductivity (measured in mV). All of above mentioned elements (caps, coils, black quadratic elements) had conductivity greater then 100mV, except one black quadratic element which had conductivity less then 1mV althought they had the same number written on them (all four elements were the same model infact). I suspected this was a faulty element so I diconnected it from the mobo (actually, I disconnected only one pin).
4. Then I turned it on again and I was surprised to see a POST screen. BUT (why there always must be but???), it was just the beginning of the POST. The screen looks like this:
- On the top of the screen was AMI logo,
- under that was CPU detection string saying: "Intel Celeron 2.4 GHz (100*24) ... bla bla bla"
- then the line saying: "F2 Setup F11 Boot Menu"
- and on the last line on the screen was BIOS ID

But that is all, I can't enter the SETUP, it doesn't continues to detect IDE devices, the keyboard isn't working.

Now what I suspect is that black quadratic element was something important, obviously. Maybe voltage regulator, but it has only 2 pins connected to mobo. If I press Num Lock, Caps Lock or Scroll Lock, no LED powers on keyboard. Voltage between USB GND and +5V is only 0.2V???

I can say that I am a computer guru :), I have repaired many computers and computer hardware by myself, but now I need help and I hope somebody can help me, because this mobo is not totally dead (POST screen shows up).

I will provide you with more info if needed!

Thanks in forward,
Amir Ahmetovic
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