Computer won't start after changing HSF

dukdukgoos

Golden Member
Dec 1, 1999
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I just replaced a very loud HSF with a quieter one on a Sempron 2800 box I built for my dad and now it doesn't work all (worked fine before with the loud HSF).

When I did the replacement I dropped the CPU about 2 feet to the floor. The housing of the CPU looked fine, but a couple of the pins were slight bent. Bent them back straight and popped the CPU back in.

After reconnecting the rest of the box it doesn't do anything at all when hitting the power switch. If I unplug the power supply for a few minutes, plug it back in, and turn it on, the CPU fan will run for 2 or 3 seconds and then quit. No beeps.

Did I kill the CPU when I dropped it? Didn't seem like a bad drop at the time, but now I'm having these problems..

Any ideas greatly appreciated...

UPDATE: I left off a piece of rubber that goes between the backplate and the MB when installing the HSF, so there was bare metal touching the back of the MB. After putting the piece of rubber back on, the fans stay spinning, but still no POST. Have tried an alternate CPU with no luck. Get MB beeps only when I remove all the RAM from the system.
 

mechBgon

Super Moderator<br>Elite Member
Oct 31, 1999
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Check the third and fourth photos on this page for one possible issue. Also, you used a fresh application of high-quality thermal grease or an unused phase-change patch, correct?

edit: ooops, Sempron 2800+ would be a Socket754 part, so the heatsink's symmetrical :eek: What are the full specs (mobo and etc) and did you happen to unplug the ATX12V cable when you were working on it?
 

dukdukgoos

Golden Member
Dec 1, 1999
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MB is ASUS K8S-MX Socket 754. HSF is Arctic-cooling Silencer 64. It looked like it'd only go on one way. I don't have any other s754 chips to try out to see if the CPU's the issue.
 

mechBgon

Super Moderator<br>Elite Member
Oct 31, 1999
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I guess try reseating the RAM, cards, and CPU (unlock the socket, hold CPU down firmly, re-lock). Good luck! :confused:
 

dukdukgoos

Golden Member
Dec 1, 1999
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Tried reseating everything, reapplying thermal grease, still no go. Fan runs for second or two, then stops. No beaps, no post.
 

stevty2889

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Dec 13, 2003
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Try with the bare minimums, disconnect hard drives, cd/dvd drives, and PCI cards. Use a single stick of ram, the video card, and the CPU with heatsink and fan, and see if there is any differance. Then try without the ram and see if it beeps, then do the same with video card. If still nothing, it's the CPU, Motherboard, or power supply.
 

dukdukgoos

Golden Member
Dec 1, 1999
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I discovered it's probably not the CPU. I got access to another s754 sempron chip to try in the board and it did exactly the same thing. So it's a MB, RAM, or PSU issue (nothing else is connected). Weird that it was working fine before making the HSF switch, although I hadn't run the computer in a few days so I suppose it's possible that it didn't work even before making the change.

I've been running with minimal components all through this testing: CPU, 1 stick RAM, on board video.

I guess next step is to try another power supply...
 

dukdukgoos

Golden Member
Dec 1, 1999
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Ok, I think I know what happened. The HSF had a piece of rubber between the backplate and the HS. The instructions on the box we're very clear but made it look like the rubber should be removed, so I took it off. That means the bare metal of the backplate was touching the back of the MB.

When I put the rubber back on, the CPU fan will now run constantly (doesn't shut down after 2 seconds any more), but I still don't get any beeps or a POST.

Did I perhaps fry the MB by having the bare metal of the backplate against the back of the MB? If so I'm pissed, cause the instructions didn't show the rubber anywhere...
 

rstove02

Senior member
Apr 19, 2004
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Originally posted by: dukdukgoos
That means the bare metal of the backplate was touching the back of the MB.
Any electrical conductive item touching any part of a motherboard other than the isolated screw holes for the standoffs where the motherboard mounts to a case is a recipe for disaster.
 

w00t

Diamond Member
Nov 5, 2004
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its the psu my vote. when you hit the power button do the fans spin for a sec like its gonna start up than it doesnt? that would be psu. ram would most likey give you a beep or reboot ur comp.
 

dukdukgoos

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Dec 1, 1999
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Now that I put the rubber backing back on the backplate the fans stay spinning, but there's no beeps or POST (monitor doesn't act like it's getting a signal)
 

Topweasel

Diamond Member
Oct 19, 2000
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This might take awhile but you maybe making contact with the case where you haven't before. Get some cardboard and build up the computer out of the case and see if it will work.
 

dukdukgoos

Golden Member
Dec 1, 1999
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Okay, I tried taking the RAM out and got some beeps from the MB, don't know exactly what that means...
 

Topweasel

Diamond Member
Oct 19, 2000
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Memory is checked first before anything else, so if your getting a beep code from that chances are your board is fine. Maybe your Monitor, screw it in to make sure its fully connected.
 

duggyb

Senior member
Feb 20, 2005
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id have to say PSU....sounds like your PSU is trying to fire up but must have an internal problem so it starts up for a couple seconds and then shuts down...even if you just got buy a $25 generic PSU and try it its worth it!

THNX
Duggy
 

dukdukgoos

Golden Member
Dec 1, 1999
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Monitor works when plugged into another computer. Also, I tried running the video off of a spare AGP card with the same results.

I only get beeps from MB when no RAM is installed.
 

Oyeve

Lifer
Oct 18, 1999
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Try a PCI vid card. Ive seen this happen. Actually to me once. The CMOS and bios went out of whack and I had to put in a PCI vid card to get all the settings rights again.
 

dukdukgoos

Golden Member
Dec 1, 1999
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Originally posted by: Oyeve
Try a PCI vid card. Ive seen this happen. Actually to me once. The CMOS and bios went out of whack and I had to put in a PCI vid card to get all the settings rights again.

I tried both the onboard video and a AGP video card, both with no luck. I don't have a PCI video card to try.