Hi Barry,
Thanks for your reply, however I found a way. Unlike your two solder pads, my Typhoon3500 model, basically a Mio 168, didn’t have the pads, must be a dif' board config. So I traced the live wire in the plug and interestingly the left hand side of the plug the 2nd & 3rd pins seem to carry the Positive feed and the neighbouring pins nothing . I tested the corresponding pin on the board using the chassis as an earth and the Charging light came on and the unit powered up (battery taken out). I roughly soldered a wire to the 2nd pin in on the board but couldn’t avoid crossing the 1st 2nd and 3rd pins so the joint crossed the 3 pins. I soldered the Ground/earth to the old socket chassis connection point on the board. I connect the wires to the Wall charger (The Yellow wire from the charger unit is the Positive not the Red), the Black wire is the Ground/earth. I Switched it on (without the battery in at first) and it came alive, left it on for 30 minutes to see if it would blow-up and it didn’t. I hard wired a circuit socket from an old gameboy unit to the wires and glued it to the case so it sat in side the case flush. Test again all OK. I Connected the battery. I then plug it into the Wall Charger and it charged the battery up as per normal , battery indicator going up & down, When the battery was fully charged the Green light came on. I had it plugged in the Wall socket for 6 hours now and all is still working. So there is another way of repairing it.
Regards Rob M