Hi all, I got the same problem : failed to turn on after charging and found out the issue: it's the supply barrel jack! Let me explain: (1) I tested the NiMH battery and it was good (voltage & discharge charge current) (2) I tested the motor and it was good (close to 0 ohm between poles), it also worked fine when supplied around 1.3V DC (3) I tested the switch and it was also good (4) I came to suspect the diode between the supply jack and the positive supply but by rebuilding the schematic, it could not be suspected Then I tried to connect directly the battery to the motor bypassing the PCB and found out it worked fine. So the only remaining component was the supply jack!! It's not a dual pole jack, it's a 3 pole and I think the issues lies here: the 3rd pole is switched open (or close) when inserting the supply jack and this prevent the trimmer to start when it's charging. As I didn't want to buy another supply jack, I just soldered 2 small cables between the battery and the motor and exited the device...