Biostar U8668 Pro CPU issues

[DankEngihn]

(Reposted because the symptoms have changed, the original post was months old, and in the wrong section)

I have an old Biostar U8668 Pro motherboard that unfortunately doesn't seem to want to work properly. None of the caps (pretty much all OST caps) are bulged, which doesn't necessarily mean they're good.

When I power the board on with either SDRAM or DDR RAM, I get an low-pitch beep for a few seconds, then a high pitched siren, indicating CPU failure or overheating, but doesn't shut off like it used to.

What gives me hope that the board somewhat works is that if I boot it with no RAM at all, I get a solid continuous beep, indicating "no memory detected" so the BIOS at least gets far enough to initialize the RAM.

What capacitors, or components are the most likely to be bad? Just to see if I can get the board to at least POST successfully, just so I know it's not a lost cause.

[cpt.charlie]

Re: Biostar U8668 Pro CPU issues

What capacitors, or components are the most likely to be bad?

VRM area capacitors are the most common to fail.
I would test the board with a different processor, maybe ypu have a bad cpu or non compatible, if you have an external programmer a bios reflash could help to discard a bad bios, also check if the board is bent specially on the chipset area, maybe the issue is caused by a bad solder.

[DankEngihn]

Re: Biostar U8668 Pro CPU issues

CPU works and is compatible. (2.4 GHz Pentium 4) I'm pretty sure that the CRM capacitors are bad, because of a crappy power supply that died.

[Dan81]

Re: Biostar U8668 Pro CPU issues

CPU works and is compatible. (2.4 GHz Pentium 4) I'm pretty sure that the CRM capacitors are bad, because of a crappy power supply that died.

Knowing Biostar, replace all caps and it will work fine.

I had a P4M800-M7 that didn't POST until I replaced ALL CPU, AGP, PCI and RAM caps with newer caps. In my instance, VRM high was KZG, VRM low was TK (OST's lowest quality caps) and the rest were G-Luxon LZ. I replaced the high and low VRM side with Rubycons, and replaced the G-Luxon LZ with G-Luxons dated after the Teapo merger, and from a series that I was sure it would last.

Board still works to this day, but I usually try and avoid VIA chipsets and go for Intel, though some of the VIA chipsets are alright, like the 693A,KT133A and the K8T/K8M series, as well as PT800 and PM800 for Intel.