T23 Battery Charging System Problem

[Harryc]

I have a T23 that powers up fine without the main battery installed, and on AC power only. If I install the main battery it is dead. No lights ... nothing on power up.
The battery is fine because it was tested in another T23. Water was dropped on this machine. Any ideas? I suppose I need to check fuses. Where to start?

[rkawakami]

There may be a problem with the power controller chip. A Maxim MAX1631, I believe. Located between the two large inductors just to the left of the keyboard connector. I understand that there's a voltage monitoring function designed into this chip. Any anomaly and it is supposed to shut down (or not even start up properly). Doubt that the battery fuses are the problem if the system refuses to power up with a battery installed AND an AC adapter connected. To me, if the system runs fine with just the AC connected (no battery) but doesn't power up when you slap in a battery, then there's something wrong with the power controller circuit. If the fuse(s) were blown then I'd think that the laptop would operate the same whether there was a battery installed or not. The T23 battery fuses appear to be located next to the battery terminals:

http://www.rkawakami.net/ibm_t2x/main_fuses.jpg

[Harryc]

Ray, thanks for the reply. If it's a Maxim MAX1631, that repair is beyond my capabilities, so this will become a Donor board. I'll check fuses anyway, but am not hopeful.

[RealBlackStuff]

It could be that MAX chip.
I've also had a very similar problem, but in my case it was caused by a defective I/O board (the strip with the ports on it).
Replacing that solved it for me.
There was no water spillage involved in my case though.

[Harryc]

RBS, I'll keep the I/O board in mind. Thanks.

[jronald]

Harryc
I have a couple of donor T30 boards
If you get brave, Ill give them to you for the cost of shipping

Ron

[Harryc]

Ron, that is a very generous offer, thank-you. If I can identify a component that needs replacing I'll contact you.

[Harryc]

Ray, you were correct, it is not a fuse problem, I checked every one. I think this board will become a donor. It had a water spill by the previous owners description, but I'll be [censored] if I can see where because the board looks perfect. It must have been a tiny spill that hit just the right spot.

[RealBlackStuff]

I would still suggest another I/O board, in case that got 'watered' too.
Cheaper than a mobo.
http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 0283355796

[Harryc]

RBS, let me ask you this. If I just disconnect the present I/O board, would the T23 still power up and charge a battery if everything else was functioning properly?

[RealBlackStuff]

AFAIK no, it won't.

[Harryc]

OK thanks, I'll try it and post back with results.

[SMA]

It is not clear to me if this T23 will start on battery only. Please clearify.

Remember that the default BIOS setting regarding SpeedStep is 'automatic', which means that the
machine will only run at full speed when both the AC Adapter and the main battery is installed.
It could be a problem that only occurs when running at full speed - not related to the battery, except that it is triggered by the
batterys presence.

Pay attention to the charging level of the battery when testing. If the battery is already fully charged, then the T23 should not start
charging it. Knowing about this may rule out the battery charging IC (adp3806).

Did you inspect the mosfets (8 legged chips) sitting close to the battery connector ?
Also the area surrounding the TB6808F should be inspected carefully.

I find it unlikely, that this is an issue with the MAX1631.

[Harryc]

The T23 will not start with a battery in it. That is either on battery alone, or with both battery and AC adapter plugged in.

[SMA]

So, it does nothing on battery only. That invalidates some of my previus suggestions.

And no lights. I will take that as the power led being off after the battery has been inserted - even before pressing the power button.
In that case the error will have to be within the circuitry that is receiving power, even when the machine is "logically" turned off.
That greatly reduces the number of possibilities, but somehow it brings the MAX1631 back in as a possibility.
It also indicates that (most likely) the Embedded Control is in trouble, but that can be just its VCC missing.

Are there no signs of where that water was dropped?
Could be a remanent from the spill still sitting in there.
Could be the battery voltage being shorted to somewhere where it should not be.

I believe that both the TB6808F and the H8S/2169 (the EC) are sensing on the battery voltage and they both have many tiny legs sitting close to each
other. You could try cleaning between the legs of both of these chips - destilled water will do for the cleaning.
And while at it, you might as well include the MAX1631 in the cleaning.

And about an experience of my own.
I am currently working on an R40. It would not turn on. It was clearly visible that someone had been soldering on the EC.
I discovered that the EC chip had 2 legs erroneously solder together.
A tiny touch with the soldering iron solved it and so far no other MB errors has been discovered. All PC Doctor tests passes.

[Harryc]

The I/O board arrived Saturday and I installed it this morning. The same problem occurs after replacing it. Anyone have a working T23 systemboard? I'll trade a 5400rpm 40GB Hitachi hard drive for it