Why does my R51 spontaneously reboot?

[Neil]

I was going to give this R51 type 2888 with Intel graphics to my mother-in-law. I had done all my testing and set-up on AC power and all seemed fine with or without a battery installed, but as I starting showing it to her the other day, running on battery power, it would suddenly blink off and reboot in a continuous cycle.

Booting Windows from the HDD it reboots just as the desktop finishes loading.

If I boot a live Linux CD, it will reboot before the CD finishes booting.

Tried a couple of different batteries, just in case, but that didn't make any difference either. As a side note, the battery does seem to charge normally when connected to AC. Also discovered the CMOS battery was dead, so changed that but still the same.

If I don't boot any drives, just bring up the BIOS, it does not spontaneously reboot, even on battery power only. So, what does that indicate? Any ideas?

Seems to me to be a motherboard problem, like maybe the IDE controller or Southbridge chip (is that the same thing?), but was wondering what you folks think.

Edit: Well, I put a little foam on top of the Southbridge chip, and that seems to have stopped the rebooting. But, now it will just lock-up with a non-responsive desktop after about the same amount of time. Still only on battery power, though. I'm writing this right now using the R51 in question on AC power. Everything, including USB, seems to be working fine on AC.

[jronald]

For what its worth, my wifes first 51 was and Intel, and did the same thing. I got a stupid cheap deal on an ATI graphics, loaded the driver on the HDD and swapped it over.

Ron

[Neil]

Thanks Ron. They say misery loves company. So I guess it helps to know I'm not suffering alone.

[CFoo]

Have you tried swapping out the memory? If you have 2 modules, try one of them at a time.

[Neil]

Well...no, I suppose I have not. I did run memtest86+ while connected to AC with both modules installed, and there were no errors after 3 passes. Also ran HDD diagnostics, just for fun, and no errors there either.

Guess it won't hurt to pull a RAM module this evening and give it a shot. I'll let you know if it makes any difference. But, I'm convinced the Southbridge BGA is faulty. We'll see.

[Neil]

OK, no surprises. Swapping RAM modules around didn't make any difference.

[jronald]

Hey Neil
Got the joy of driving I40 from Raleigh to Ashville, no sign of construction anywhere along the more than 200 miles.

Ron