GTA02 fails to charge

[Phil Vandry]

I have 2 GTA02v6 Freerunners which don't charge their batteries anymore. 
The symptoms on both are the same, but it started happening on both 
phones in different locations and times. The battery state is "Charging" 
whether the phone is plugged in to a computer or wall charger, but the 
battery slowly goes down instead of charging.

We use the phones in airplanes, connected to 5V DC power supplies. My 
wild guess is that both units might have experienced a power surge or 
something that fried the charging circuit (RT9711BPB chip in socket U4905?).

With 2 Freerunners affected and afraid it might happen a third time, I 
would like to know if anyone else has experienced this problem.

-Phil