Defective CPU or mobo ?

Over the past 12 months, I've built more than 30 systems based on
boxed Athlon XP processors and Asus A7N266-VM mobos, and never had any
problem until very recently. One new CPU, a 2000+ Thoroughbred, failed
completely (confirmed by cross-substitution), giving continuous
high-low BIOS beeps. Another new case, a 2400+, is harder to pinpoint
because the fault is intermittent. It has never failed during usage
but sometimes refuses to start up, sometimes silently, sometimes with
high-low beeps. Resetting the BIOS by removing the battery and
discharging the CMOS enables it to start again, even if the RTC and
BIOS settings are immediately changed to preference again. Battery is
OK and replacement makes no difference. Even just removing and
reinstalling the battery restores it without shorting the "clear"
pins. One indication : It seems to be OK as long as the BIOS time/date
is not adjusted (NOT confirmed). Hard to confirm this because the
fault sometimes takes days (hours at the least) to reappear although
this particular computer is normally turned on and off several times a
day.

At first I thought it was probably a faulty BIOS chip, but the other
dead CPU, so closely followed in time, makes me wonder. I live in a
small isolated town and get all my supplies from a city more than
500km away. My point of purchase will replace confirmed defective
products without fuss, but I'm reluctant to remove the CPU for
substitution because the AMD-recommended "thermal interface" is not
available here or with my supplier. I have normal electronic heatsink
compound but not the special AMD gunk.

I've eliminated other obvious factors like memory, power supply,
drives, etc. I'll be grateful for any suggestions.

-Zotin

Zotin Khuma wrote:

 > Over the past 12 months, I've built more than 30 systems based on
 > boxed Athlon XP processors and Asus A7N266-VM mobos, and never had any
 > problem until very recently. One new CPU, a 2000+ Thoroughbred, failed
 > completely (confirmed by cross-substitution), giving continuous
 > high-low BIOS beeps. Another new case, a 2400+, is harder to pinpoint
 > because the fault is intermittent. It has never failed during usage
 > but sometimes refuses to start up, sometimes silently, sometimes with
 > high-low beeps. Resetting the BIOS by removing the battery and
 > discharging the CMOS enables it to start again, even if the RTC and
 > BIOS settings are immediately changed to preference again. Battery is
 > OK and replacement makes no difference. Even just removing and
 > reinstalling the battery restores it without shorting the "clear"
 > pins. One indication : It seems to be OK as long as the BIOS time/date
 > is not adjusted (NOT confirmed). Hard to confirm this because the
 > fault sometimes takes days (hours at the least) to reappear although
 > this particular computer is normally turned on and off several times a
 > day.
 >
 > At first I thought it was probably a faulty BIOS chip, but the other
 > dead CPU, so closely followed in time, makes me wonder.

Given the other system gave the same beeps, I'd be leaning towards another
CPU. I've used a bunch of those boards as well and they work great.

--

Stacey<!-- ~MESSAGE_AFTER~ -->