Why my iBook won't power on from battery?

Hi all, am hoping you can help me with my dilemma here. I bought an iBook off of eBay a couple of years ago and battery doesn't hold charge. The adapter light turns from orange to green then back to orange erratically. Battery icon showed either 'X' or 0%. I replaced the DC inboard because the adapter pin got stuck in there. It works perfectly when plugged in (apart from erratic battery behaviour). I have just bought a new battery hoping it would solve my problem. But here's the thing:

1. When I plugged in the AC adapter, it turns orange the whole time it's stuck in but it doesn't charge the battery.

2. Battery stays at 29% and I got two lights on the battery indicator.

3. Coconut battery says I have 29% as well but it tells me that battery is not charging.

3. System Profiler also says battery is connected but doesn't show as charging.

4. I left the laptop on sleep and hoping it would charge overnight but nothing happened the next day. It is still 29%

5. I tried to turn laptop on without the AC adapter, but it won't turn on, not even a blink.

6. I have reset PRAM, NVRAM and PMU to no avail.

Are these signs of bad logic board? Thanks guys!