PowerBook G4 (12-in): known good battery unrecognized.

Hello all,

I recently purchased a 12-inch PB-G4 off eBay, with a known (to the seller) good battery. I found upon initial use that the battery did in fact power the laptop, and charge, and I got it up to 23% before I began having problems with it. The problem was one that I've seen from Google is typical of the PB-G4; and that is, that the battery info from the OS X menu bar shows "battery not charging", even though the power adapter is powering the laptop just fine. I have searched this problem pretty thoroughly online, and have yet to find where anyone actually solved it, even though they've tried new batteries, new power adapters, PRAM resets, PMU resets, NVRAM resets, leaving the laptop plugged in, etc., etc., etc.

I myself have tried the following:

• PRAM reset
• PMU reset (all 3 different ways to do it)
• removing/reinserting the battery
• leaving the laptop plugged in, with battery, for 24 hours
• draining the battery completely, in an attempt at battery calibration
• different power adapters (one 45W & one 65W, both known to be good)
• different operating systems (Leopard and Tiger)

None of the above have made a dent in the problem. In fact, after completely draining the battery (it powered the laptop for a good 20 minutes before finally dying), the battery level info from the menu bar just showed 0%. After a couple days, it just stopped recognizing the battery altogether.

I believe this to have been a good battery; when the problems began I checked the "Power" info in System Profiler, and it showed that the battery was good. I cannot remember the numbers that were displayed for cycles and such, however I do remember that there wasn't anything ridiculous showing there (such as cycle counts in the tens of thousands, which would tend to indicate a bad battery).

So, here's my question: could the problem here (assuming of course that the battery really is good) possibly be a bad DC-to-DC board? I don't know exactly what the DC-to-DC board does, but it's name leads me to suspect that it has something to do with regulating power to & from the battery.

The reason I ask is that in all my googling, I have yet to find anyone who has suggested the DC-to-DC board as the culprit, or anyone who has tried to solve the problem by replacing that part. I have seen numerous suggestions for other things, like replacing the DC-in board, getting a new battery, new AC adapter, etc.; none of which have seemed to work for anybody.

So, before I plunk down $$ for a DC-to-DC board, or a new battery, I thought it might be worth asking the question. Answers?