Have you tried 1234 or 0000?

Or use a voltage tester,(on DC that is) on the battery and check to see if you have 14 volts. If you do then its fine.

Have you setup a combo before?

I agree with rab777hp, it sounds like a battery issue. Iam waiting for my replacement battery from iFixit as well, hope all goes well. Also leaving any device with a rechargable battery for long periods of time is not a good idea. Unless the charger has a peak charger where the charger will shut off automatically, do not leave the battery unattended. This will just ruin the battery sooner. Hope this helps