Hi Fahmi, sorry for the late reply. I must admit, I ended up not delving very far into the repairing the PCB. I couldn't find any obvious component failures or other problems on the PCB. The motor worked OK using an external power supply and I also I tried using the external power supply instead of the battery, but the problem remained. I didn't look into a replacement battery and ended up sending it to e-waste. Regards, Jim.