RE: JR radio
Ciur
The voltage spikes should not have damaged anything. What I suggest is to remove the battery pack from the TX and check the voltage with a voltmeter. You can also check the voltage on the charger.
I suspect that after the pack was run down the charger that you are using does not charge the pack. If you don't know enough about the electronics involved, take the battery pack and the charger to a TV repair shop. Ask them to test it for you.
Hope this helps. Don't give up.
Safe Flying!