Makita Battery/Charger Question

I purchased a 12V Makita drill (6216D) about 2 years ago. It came with two of the gray 2.2Ah Ni-MH batteries and a charger (DC1411). From the very beginning, it did not seem to me that the batteries were holding a charge very well. I could charge a battery until the green light came on, remove the battery put it in the drill ... and come back 2 weeks later and there was very little power left in the "fully charged" battery.
I previously owned a Craftsman Professional 9.6V drill with NiCad batteries (which I suspect were nowhere near 2.2Ah) ... and it would hold a charge for several months. I think I've read that Ni-MH batteries will lose their charge quicker than NiCad batteries ... but I wouldn't expect a "fully charged" battery to lose most of its charge in 2 weeks!
My problem now is that I can't seem to get either of the Makita batteries to fully charge. I've tried only leaving the battery in the charger for an hour ... and I've tried leaving it for a week. Neither way seems to fully charge the battery. One thing that seems strange ... after charging a battery for a couple hours, I can remove the battery ... wait a few minutes ... and then plug it back in to the charger ... and the blinking green light turns red and stays red like it is doing a full charge cycle. (I have not timed it to see how long it stays red, although I suspect it's not very long.)
So ... my questions:
(1) could the charger have been "bad" from the very beginning? (2) is there anyway to rule out the charger as the problem with a v/o meter? (3) is it more likely that the batteries are "bad" (and maybe were from the beginning)? (4) what's my best course of action to diagnose my problem?
One last question ... does it harm the battery or the charger to leave a "fully charged" battery connected for weeks?
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Crappy cells. Yes, it can happen.

It is checking for charge. No, i t will not stay on long.

Possible, but I think it is the cells, not the charger.

Yes, very possible. Too late now though.

Check each cell. Of course, you have to open the pack to do that. If you check the voltage right after charging, if you are getting less than 12V you can be sure cells are dead.

Depends. Not on most new equipment.
You can always have the packs rebuilt better than new at www.primecell.com See http://www.primecell.com/pctools.htm the 12V is $33.

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