I have just been given one mp3 player with board MP 693C SL MAIN Ver1.3.
My problem is that it only works when connected to usb... not in standalone mode...it does not recharge battery.
I opened it... and as expected the battery has a couple of cables loose.
They ony one that is soldered is the red, but battery also has two more that are unconnected ( a black and a white).
I assume that the black one will have to be soldered beside the red one.... but do not know what to do with the white one.
I am attacching a picture of a similar board I found in the web...It is not mine... its battery has two cables ( red, black) while mine has three ( red, black, white..).. the red one is in same position.
I just soldered only the my black one in the same position as the black one of the picture...and the problem persists.. mp3 player only works when connected to usb.
So do not know where to sold the white ...