T43 Charging Issue

[l33tpr0digy]

I've had my T43 for about 5 years. It's been a great laptop without many problems. About a year ago, I noticed that it would no longer charge the battery. Since I only used it when I was at my desk at work, I never had a problem leaving it plugged in. Recently, I've started being out of the office a lot more and would like to take my Thinkpad with me. I've tried another known working power adapter and also purchased an after-market battery that I have confirmed charges in another working Thinkpad. If I remove the battery, the laptop runs fine on the AC adapter, and likewise, if I disconnect the power adapter, it will run find on battery power.

I searched the forum for similar situations, but I couldn't find anything. I feel that the charging circuit on the motherboard is not working correctly. Am I correct in this assumption? Has anyone else had this problem? If so, is there a fix? I'm pretty good with simple electronics repairs, but I'm not exactly sure where the charging circuit is located on the board to even start looking for damaged parts. Any help would be much appreciated.

In the event that it's not repairable, is there any market for original IBM Thinkpad parts?

Thanks.