CPU Fan Gone Crazy!

[VealChop]

Hi all. I'm having an issue with the CPU fan in a 2-3 year old HP Desktop and not sure if the problem is with the Mobo or the PSU. The computer was working fine until about 3 months ago when the CPU fan started racing non-stop. The computer still functioned fine, though the fan was running at full speed. I cleaned the case, plenty of dust in there, thinking that was the problem, but didn't help. I have never removed the heat sink from the CPU, so i didn't think that was the problem. Now the CPU fan races, then idles, then races then moderates....basically it is all over the place. The comp still runs, no real issues during use. Just an insane noise coming from the fan, sounds like a race car revving its engine.

Also, a little while after the fan started racing, a printer i had on the serial port stopped working, as did the speakers. This got me thinking it was the Mobo, but before i replace that, just thought i'd ask for an expert opinion.....any thoughts???

AMD Athlon XP 3200+
Starlogic (cruddy and quite light) 300w PSU
Don't see any brand name on the mobo, (Comp model is HP pavilion a520n)
512 MB DDR memory no-name brand

Any ideas greatly appreciated....

[Jester]

I am going to go with your mobo as being the problem. If your speakers, and serial port stopped working I am thinking that there is a short on the mobo that is causeing heat issues which is why the fan is racing. Look for burn marks around the resistors, and capacitors on the mobo.

[VealChop]

That's what i was assuming also... I've looked over the Mobo, at this point, the comp is completely disassembled in front of me, and i don't see any signs of trouble, no bulging capacitors, leaks, evidence of burns etc.

Before I order a new one, is it at all possible for these problems to be caused by a faulty PSU? It would obviously be much easier to change that out and not have to reinstall Windows etc. (I don't have the XP Home CD, HP comps just give you that OS partition on the HDD).

If i did have to change the Mobo, this is a socket 462, with an AMD XP Athlon 3200+. I'll be keeping the CPU, is there any other Mobo this can fit into? And if i have to stick with Socket 462, I don't see many out there, just a few....I'm looking at this one right now, any thoughts?

http://www.newegg.com/product/produc...82E16813186029

Has to be micro ATX as I don't think ATX will fit in this case.

[glc]

Unless you want to buy a new copy of Windows, you should buy an exact replacement board on Ebay. It's an Asus A7N8X-LA, these are pretty common, but they ARE proprietary HP.

http://cgi.ebay.com/ASUS-A7N8X-LA-HP...QQcmdZViewItem

It would certainly be easier to try a new power supply first.

Serial port? You sure you don't mean parallel port?

[VealChop]

Yes sorry, parallel port.
Looking in the BIOS, hardware monitor, I notice the CPU temp jumping around wildly. 36c, -12c, 98c, 45c, 110c! The heatsink is not even warm to the touch. Sound more and more like a Mobo problem?
Thank you for that link, I guess that's the only way to avoid purchasing Windows XP over again. A little more than i thought it would be, over one hundred for an outdated mobo like that? Wow!
I'll have to think about that one. Anything else i can do???