If you have an Older Phone try the Batteries from it in the newer one. And see if it's the issue. So, you don't have to spend money. Or try the batteries from the older Phone in the new one also be careful about buying Refurbished items/Used because they might have put a wrong base in the box.

Have a slightly different problem. 1 out of 4 handset is forever charging even though battery is full. I can put a known full battery (shows full in other handsets) into this one and it will show 1 bar. If the handset charging circuit think battery is not full. All of this without the charging station. The charging station is fine as I can put other good handset in there and battery charing behavior is correct (shows charge complete when full) · So obviously if the handset thinks a full battery is not full, then its always charging and generating heat like what I am seeing. Going to probe the circuit board (pic below) for voltage readings. Looks like there are diode on the battery side also. Wondering if others have had this problem. · I have 4 handsets and using a known good fully charged battery, I get 2 handsets showing 1/3 bars, 1 showing 2/3 bars, and only 1 handset showing 3/3 bars. · Dug a bit deeper into the schematic (didn’t find exact but perhaps close) Battery voltage is fed to the IC (likely pin 58 of basedband IC SC14430). IC reads voltage and make decision to trigger the external charge circuit (transistors + diode system). 3 Voltage islands on the handset board (3.3V, 2.5V, 1.8V) identical readings between good handset and bad one. · On the good handset, had the handset opened up with alligator clips on battery post for 2xAAA power supply. The alligator clips accidentally touched the 2 charge terminals as its easy to do with the back cover off. Battery and charger terminals next to each other are reverse polarity and the good handset also shows 1/3 bar on full battery after touching. There was no spark or noise. Something must be really easy to damage with such low voltage and current.