T43 Battery/Power Problem

[RWDPLZ]

Just got a T43 I'm going to refurbish for my little brother to use at school, a 14" 1871-FU1. When you turn it on without a battery, it gives a critical low battery error, and shuts itself off.

The HMM lists the error code
0190 Critical Low battery error
1. Charge the battery pack
2. Battery pack

even though there's not one in the computer. If I put a battery in it from my T43p, it seems to work fine.

I just tried updating the embeded controller, and it told me there was no AC adapter plugged in, and I couldn't go any further.

Is this possibly a blown fuse on the motherboard? Or something simple I'm missing?

[rkawakami]

I think that the low battery error can also be explained by a weak CMOS (aka, backup) battery. You also cannot run the BIOS or EC updates without an AC adapter connected to the system AND a fully charged battery. It's basically a protection against power failure during the critical time that the firmware is being re-written. There have been some work-arounds to this but it's not something that I would recommend.

It's also possible that there's a problem with the power controller on the motherboard but that requires some detailed detective work and some luck in spotting bad components.

[RWDPLZ]

Just checked the CMOS battery, it's at 3.01 Volts, and the CMOS batteries in my A31p and X24 were both around 2.8 volts, so I think that's fine. The Battery I used from my T43p is fully charged, and it worked fine updating the BIOS with that.

[RWDPLZ]

Took it down to the bare board and tested all the fuses, and they're all good. Hmm...

[RWDPLZ]

Never figured it out, but doesn't seem to affect the performance of the computer. So I just gave him my good battery. It work fine on battery power, and the AC adapter does charge it. Weird.