EDU09 do not work well

Hello. After the assembly of my EDU09 it seems that something is wrong. All measurements that I can see in the diferents topics are OK except IC2(pin1) wich marks 1,71v. without connected software (instead of 1,53v.) and 1,66v. with software. Also, calibration was OK.

However, something seems to be not going well. When I try to test my adapter charger with dc 6v., the curve that I can see is this:


Also, it does not work for me with a battery either. Some clue?

It seems that maybe the GND lead (black) is broken.

Ok. That was. Thanks