R51 (2889-47U) will not charge, running out of ideas

[mrjonescu]

I have an R51 (2889-47U in a T42 case) that will not charge the battery. It will run and boot from an already charged battery. I have tried multiple batteries (all of which charge in my other R51 and R52). It will also run and boot from the charger, and does not drain the battery when plugged in.

My initial though was a problem with the power plug in the back, but I also hooked it up to a port replicator (which will charge my other Thinkpads) and it still will not charge.

I have also tried updating my BIOS and embedded controller with no charge in the issue.

Now I believe this problem is due to a motherboard issue. I have not checked any voltages, but I am using OEM batteries and chargers.

Is there anything else I should check before I rid it apart?

Thanks.

[SMA]

I am almost certain that this is a motherboard fault.

I have a T42 board which were suffering from the same symptoms. Turned out to be caused by a faulty mosfet.
If you decide to take the board out, then you may try to inspect the area below the main battery connector (on the bottom side of the board).
The area I am referring to is covered by a black shield, which is glued on. You will have to lift that shield, but first, see if the shield
has deformed (due to heat).