Replaced CPU cooler, no more POST, blank screen

[Peroxyde]

Hi,

EDIT: I think I have located the area of the issue. Each time I bend the motherboard a little bit or pressing the CMOS battery on its seat, the computer boots but doesn't recognize the hard drive (or detected the HD with corrupted chars ex: MaHt0r instead of Maxtor.Not sure whats going on but it definitely not the CPU

I am trying to fix an unstable computer. Although not perfect but the computer was working. The computer hangs when running Prime95 for 10 to 30 minutes, probably due to overheating, so I decided to swap the CPU cooler by a better one. Now when I boot, the screen is totally blank. Either with the onboard video or with an external AGP card.

The changes I have notice after the change of the CPU cooler are:

- HD led is always on

- no beep when boot

- video totally blank (when VGA unplug the screen flashes "No Signal", when plugged in, there is simply a blank screen)

NOTE 1:
- all fans, lights seems to be working OK.

- also tried with another working PSU, same issues.

- Monitor working OK with another computer

- If I stop the CPU fan, the heat sink warms up. So may be this indicates that CPU is OK?


NOTE 2: I might have done something dangerous, when I cleaned the CPU of the previous thermal grease. There was some spill under the golden pins that I have clean off (using nail polish remover). I left some tissu dust on the CPU pin grid (motherboard side) and brushed off with a tooth brush. Then I put CPU back and assembled the cooler.

Question: Is the behavior above consistent with a bad mounting of the CPU?



Detail hardware:
The motherboard is Biostar P4M800Pro-M7 http://www.biostar-usa.com/mbdetails.asp?model=p4m80-m7

The CPU is D830, 90 nm, 130 W http://processorfinder.intel.com/details.aspx?sSpec=SL8CN

1 GB module, Memtest86+ v2.11 OK (4 passes successful)

PSU: Antec True power 480

 

[BababooeyHTJ]

Did you break or bend any pins in the socket? You should have just used some compressed air and maybe some alcohol to break up the paste. I wouldn't do poking around in my cpu socket with a toothbrush.

 

[Peroxyde]

Did you break or bend any pins in the socket? You should have just used some compressed air and maybe some alcohol to break up the paste. I wouldn't do poking around in my cpu socket with a toothbrush.

I have removed the CPU heat sink, removed the CPU and looked at the bottom of the CPU and the pin grid on the socket with a magnifying glass. Everything looks OK.

I have tried to boot without the CPU cooler several times, just a few seconds to see if the boot screen will display and power off. Each time, I loosed and rearm the CPU holder on the socket hoping that this would make a better contact somehow. No change, screen is still blank. Then I re-assembled the CPU cooler again.

In desperation, I wonder if this could be the CMOS battery. I push on top of the battery (and maintain the pressure with my hand. And strangely enough, I could make the boot screen come up. After that I rearranged the battery contact, retried several times, but no success.

What is around the CMOS battery area that could prevent the motherboard from booting?

 

[topdog5252]

Well it sounds like you may have something shortening it out are you got a loose connection somewhere on the board it could be around where the battery goes in.Ihope you havent nicked any of the leads on the motherboard that could also be a issue.Have you pulled the board out and went from there?Another battery could be the trick.If you would post some pics and let me look at it in some good light and you can go from there if that dont help any pm me and keep me updated on this issue.Good Luck.

 

[Peroxyde]

Well it sounds like you may have something shortening it out are you got a loose connection somewhere on the board it could be around where the battery goes in.Ihope you havent nicked any of the leads on the motherboard that could also be a issue.Have you pulled the board out and went from there?Another battery could be the trick.If you would post some pics and let me look at it in some good light and you can go from there if that dont help any pm me and keep me updated on this issue.Good Luck.

Hi,

thank you very much for your help. Replaced battery and moved board out of case didn't solve.

After a few days struggling with this troubled old computer. I think I have stabilized some how. Quick summary is some defective parts: video board, IDE cable, the clip that hold the battery was loose and the RAM was too slow for the default automatic speed of the motherboard. Strangely enough these component are not 100% dead, sometimes they work, sometimes not. When all of them combined, the erratic behavior is random. On top of that, I am not very experienced and made some extra errors due to mis-dianostics.

Took me quite a while to isolate each of them. But now it seems like I can finally boot the computer successfully at every "power on".