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LeeV
05-16-2001, 11:21 AM
Hello all you happy people,

WARNING! This is a long post.

I am working on a machine that has no video. The owner of the machine decided to try to determine the problem himself, and by the time it was delivered to me it was in pieces! He said this machine was in working condition when he put it in storage. After 3 years he decided to plug it in and see what happened. It booted fine (so he says) until windows appeared, and then it displayed the mouse not detected error. He decided to check the connection (while computer was on) and noticed mouse cable was tangled up in the monitor cable. While he's messing around with the wires, he loses the video display......

Here is a list of hardware:

Unknown motherboard
-baby AT form factor?
-award bios (vendor is blank on bios chip, and I cant see bios string)
-socket 7
-4 72pin Simm slots (supports FPM and EDO)
-1 168pin Dimm slot
-onboard IDE, Floppy, USB, and SCSI
-3 PCI, 4 ISA, and what looks like maybe a riser card slot?
Generic ISA Video card

Pentium 90 CPU

16MB FPM Memory (4 X 4MB)

Sound Blaster 16 Value ISA

When he brought me the machine, the cover was already off and the machine was full of dust and spiders! I got my handy can of air and cleaned it out. I connected the computer to a known good monitor (old AST VGA), serial mouse, and keyboard. Crossing my fingers I hit the power button..... No display. The CPU fan spins, floppy drive and cd rom leds light up, and you can hear harddrive activity, but no POST display shows...

For a quick test, I pulled its video card and replaced it with a known good one. Trident ISA VGA 512k, nothing fancy works in everything else I have. No change, same symptoms. Tried S3 PCI card, same results. Original video card works in my machines as well.

I pulled the board out and assembled it on a piece of card board on table, with just power supply, cpu, memory, video card, and speaker. No display, the computer did not have pc speaker in case, and at this point I noticed no beep at power up. I decided to pull everything off the board (cpu, memory, and video card), and test the speaker. When I turned the machine on, instead of the long wailing beep I expected, I heard nothing. Yes, speaker works and is hooked up correctly. + = red, - = black.

I believe the motherboard is bad, does this sound like a logical conclusion? Could the cpu be at fault? Memory? I could put the cpu in another machine no problem, but if it's bad could it hurt my motherboards?

Just wanted to bounce my thoughts off the talented minds here and see if maybe I'm overlooking something... like just now I thought about it possibly being a power supply problem.

Thanks for any input, Lee http://www.PCGuide.com/ubb/biggrin.gif

LeeV
05-16-2001, 12:34 PM
Update...

Not the power supply. http://www.PCGuide.com/ubb/rolleyes.gif

I guess I'll try all the parts on another board...

Lee

tjaymadison
05-16-2001, 04:19 PM
You might try a few other things:

Remove all cards and RAM modules, and blast the slots with the compressed air.

VERY lightly 'scuff' the contacts on the cards and RAM with a pink pencil eraser.


------------------
"I am not able to rightly apprehend the kind of confusion of ideas that could provoke such a question."
-- Charles Babbage, mathematician, computer pioneer, analytical engine designer (1791-1871)
-- (Question: 'Pray, Mr. Babbage, if you put into the machine wrong figures, will the right answers come out?')

LeeV
05-17-2001, 10:20 PM
Just a note to end the thread,

Fixed the problem. Replacing the motherboard solved the problem. I had only one problem along the way. I put the CPU, memory, and video card on the new board, and had a memory error. The old memory had a mixed pair in one bank. Both the same size, but one double sided. The new board said no way!

Put everything back on old board and used new memory, still no video, so it looks like I guessed right, and this old board is junk...

http://www.PCGuide.com/ubb/smile.gif Lee