MB900C: charging led keeps blinking ... WTH?

Hi,
Yesterday I inherited an MP900C from a friend of mine (for free, yay! ). He told me it hasn't been used for quite a few months.
Feeling excited, but ... this morning when I turned it on (with AC plugged in), the system warned me against battery going flat. So I turned it off and let it charge. Here comes the problem. There are two batteries, a standard one and an extended. When the standard one is inserted, the charging led blinks amber; when the extended is inserted, the charging led blinks green. After a few hours of charging the blinking is going on.
So can anyone tell me if this is normal, or a battery problem, or ... a machine internal problem ?
I haven't used WinCE before until this morning. Your help is very much needed and appreciated. Thanks to all!

It shouldn't blink - it should just stay solidly on. Are you sure it's blinking and not flickering? The power jack in the 900(C) has a tendency to get loose; maybe that's the problem.

Wow. I'd not expect such a quick reply, seeing that not many ppl around are using HPCs. Thanks! ;P
Perhaps a video is worth a thousand words. I made it in a rush with my mobile... sorry for the poor quality. Yet at least you can see it.
http://www.youtube.com/watch?v=dVaK-SujD14
What's your diagnosis?

Also as I said the other (extended) battery gives a green blinking.
If the AC jack gets loose, is it hard to fix it manually? and how?

Good news! After several (6~7) hours both batteries began to charge and the charging LEDs are not blinking anymore. So this seems to happen to MP900C when the batteries are not charged for a long time.
I can now start playing with this adorable gadget.

Concerning the AC charging port, it's common on MobilePro 900C.
I've dismantled 3 units to solder the joints on the board & they all function normally after that.
It's easy to do & there's a detailed dis-assembly instruction here: http://hpcnec.com/cgi-bin/simpleforum.cgi?fid=12&topic_id=1143848182
Unfortunately, this domain seems to be down...

Konker

Both CE Geek and Konker are right. Actually the blinking problem doesn't go away completely. The charging LED still blinks sometimes. Another issue is often I see a white blank screen without anything displayed. So I couldn't resist to open up the whole thing, then disconnected and took off everything except the LCD screen, then put them back. The charging problem gets better now as the LED will go solid when powered off with AC, although it still blinks when powered on with AC. And the display behaves well. It seems both the AC jack and the LCD ribbon cable connector were somehow loose.
I googled this wonderful website with tons of info about the mobilepro series, including disassembly: http://sites.google.com/site/necmobpro/my-mobilepro/nec-mobilepros/mp900-900c

Edited by MrSB 2010-01-03 1:19 AM

That's Rich Hawley's site. (Konker's link is the link for Rich's former site, HPCNEC.) Rich staffs our site as well. (I've been waiting for him to chime in on this issue in this thread, but maybe he's out of town for the holidays. )

yes, the loose ribbon cable is another common issue, usually fixable by adjusting the connection for a while