Hi,
I am trying to repair a 'Topeak Whitelite 1W LED Cycle torch'which is powered by a 3.7 volt CR123 battery.
I had to replace the Luxeon 1 watt LED.It works correctly at full brightness when connected to a 5v supply to the 3.5mm socket (allows a separate 5 volt battery to be connected).The push button allows Full on,Flashing and off.I found the 3 pin SMD device marked 015PB,(M1 on PCB),was open circuit.I have managed to get the torch to work by replacing it with a BC327 PNP transistor on short leads,because of its size.It appears the brightness is down 50%?.I cannot find any info on the faulty device,and wondered if it was a digital transistor,or a mosefet?I know there is a LD1117 3.3v output,used a constant current device,and a 5104A device used to boost the 3.7 volt battery to 5 volt. I have attached a PCB photo,and a circuit.Any ideas please?