Laptop BIOS hangs

[j7n]

I have developed a new issue with my old Samsung R40 laptop. It will now always hang while running the BIOS. This was not so when I got it earlier this year. The computer will usually not proceed to booting the operating system. If I enter BIOS setup, I am able to adjust at most 1 setting if I am quick, before the computer locks up and must be power cycled.

If the BIOS does not hang, and starts booting into Windows XP, which happens about 1 in 5 attempts, the system is completely stable under load. I can hear the hard drive powering up and seeking, so it's not that the system is failing to read from disk.

To find the cause of the problem I have so far:

- reset BIOS to defaults, confirming that it really happened

- disconnected all peripherals and cables

- disconnected the hard drive

- removed either one of the two memory modules

- disconnected the WLAN radio

The BIOS would always hang in diferent stages. Sometimes on device enumeration, sometimes right after entering setup. I was able to restore essential settings one by one.

I am in peace if the machine is dead. I'm just kinda curious how is it that it can work in Windows stable in this condition.

[jaclaz]

Queer.

Have you checked the BIOS battery?

jaclaz

[puntoMX]

Or try to flash the BIOS, or better replace the BIOS chip with a new one, flashed with the latest BIOS you can find. Sounds like a bad chip that sometimes can't be read. Other than that I can only say it's a now faulty motherboard, hard to say why...

[j7n]

The battery sounds relevant. I'll get back when I have disassembled the PC to reach it.

[j7n]

Flashing a new BIOS version 06YE over 03YE with WinPhlash proceeded without issues. Computer could be rebooted and showed the new version. The problem remained.

The CMOS battery tested good. Battery was wrapped in a black plastic with wires, and since it was good, I didn't replace it. Resetting the CMOS by disconnecting the battery and shorting the leads also did not resolve the issue. For the first time the computer reported a CMOS checksum error. I managed to adjust only two settings, and they were preserved.

It is quite possible that the motherboard is faulty because some oxidation from a liquid could be seen on it. Soldering a chip however is way beyond my skill level.