TP T42 Dead MOBO or ... need advise

[retropolis]

Hello,
I've bought ThinkPad T42 2373-6VU 4 weeks ago. There was BIOS Pass (only for BIOS parameters) like admin000... All functions was OK.
Then I desided to replace main battery and after a replacement it didn't power up at all. No sound, no fan rotation - absolutely quiet. New Battery works great on other T43.
I opened the case and found some signs of "Coffe Stand" inside. Clean it up with Cleaner. PCB wasn't corroded to much and I think it wasn't a reason for malfunction, because it works more than 2 weeks before without any problems. Then Check all fuses - OK. Then made some "measurments" in Power Supply and it looks like no signal from voltage converter drivers to Power MOSFETs.
CMOS Battery was fully dead to.

So, the question is - MOBO dead or not? Or it just kind of protective locking bacause the BIOS Pass was set and CMOS Battery was dead? (Reading this forum before I can't understand how this LOCK looks like).

Maxim.

[lukee]

Hello Maxim, welcome to the forum!

Does your T42 mobo works only plugged with power cord and unplugged battery? If not, it really seems to be a mobo problem If you will decide to obtain some spare refurbished mobo, you can choose also T43 mobo which is quiet more modernized (SATA controller for UltraBay, PCIexpress graphics, ExpressCard slot, faster FSB etc...), it will fit into T42 housing without problems but you will need newer DDR2 RAM modules.

[Bruce Guttman]

Sure sounds dead, especially with no power to MOSFETs.

Sometimes a dead CMOS battery can cause startup failures, so the simple test is to mount a new CMOS battery (they're pretty universal; I've used ones from 600, T-23 (need to remove it from frame), etc. and they all work. Even attached the leads from a wire to a CR coin cell with tape to make a temporary one.

If you decide the MoBo is dead, the T40, T41, T42, R50 (comparable to T41), and R51 (comparable to T42) boards (and p variants) can be used. With an R5x board you may not be able to use IEEE 1394 (Fire Wire) connections because the case doesn't have an opening.

Problem with R52 or T43 board is that the PC Card cage is different, it uses a different fan, and it uses different memory (DDR-2 vs. DDR).

Try the CMOS battery first; might be the easiest solution.
Then check all the fuses; it might be that simple.

[retropolis]

lukee, Bruce Guttman, Thank you for your answers.

2 lukee,
It didn't power up in all configuration. And I think it's mobo problem too, unfortunately

Off: If I'll try to reset Supervisor (or Bios) Pass than, after reboot, I get a request for master password, is it right? And security chip replacement will help in this case?

2 Bruce Guttman
CMOS battery replacement with CR2032 - it was the first step of my TBS.
Bruce, can you tell me the difference between T41 and T42 mobo (chipset, dual or single ch memory, does T41 Video support SXGA+ resolution?)
Maybe you have some statistics which one p/n is better for replacement to avoid typical ThinkPad issues like Video chip soldering, fan noise, etc.

[lukee]

retropolis: security chip in T4x series is not easily swappable. You need knowledge + soldering tools... and then a success is uncertain because security chip can be related with mobo's SN due to security reasons.