Broken Kenwood D7-AG

I'm looking for suggestions on how to debug my Kenwood D7-AG amateur radio. There are currently 3 issues: 

1) The radio works fine running off the battery, but as soon as I plug in the Wall wart/transformer, or the 12v cigarette lighter adapter, the power goes off on the radio. It should stay on, and be charging when I plug either of these in. 

2) Sometimes, the transceiver just starts rebooting on and off. Holding down the off button doesn't help, I have to unplug the battery. I'm assuming this is when the battery level is low, but haven't verified. 

3) I took the radio apart to take a look, and noticed a ribbon became unconnected in the process. I tried to connect the ribbon before resealing the case — it seems to have worked, however I don't hear any audio anymore from the internal speakers, even when I turn the squelch off. (although I do get the APRS connection "beep" which is perhaps from a different speaker?)

It's worth noting that with all of this, when the battery is in and working normally, APRS works fine. 

The Kenwood TH D7 AG manual