There are what looks like capacitors connected - one on each side - to the pads of this mystery part. The “top” leg and the “bottom left” leg of the part are connected to opposing ends of the (capacitor?) on the left, and the “bottom right” leg is connected to the (capacitor?) on the right, the opposing side of which is connected to the spring pad. The “bottom left” leg trace also seems to go to the ground ring and some other components.
While unscrewing I stripped a capacitor and almost stripped one more part. I think the same as you did, but maybe the 5-legged one. Will check later. The legs got much longer than normal, but I didn’t see any discontinuity.
I soldered the capacitor back, moved the almost-stripped component back to place, the driver was dead.
Okay, i took some pics.
I removed the inductor to show the through holes from the ‘mystery component’.
Apparently the through holes go nowhere.
Very strange.
And another pic from the spring side:
I made blue what tests as continuous, but it’s strange if they’re really the same, because otherwise they could have bridged it right from the minus spring. (Again, the spring is minus, battery goes in bottom first).
Those should work but you should make sure it’s indeed an LDO: Vin (pin 1, top) should be connected to the battery plus; the output (pin 3) probably connects to pin 1 of the µC (a PIC12F1840).
If that’s the case, it’s pretty much confirmed it’s an LDO.
Hmmm… The other 3 legged component “D19HJ” is connected pin 1 to plus and pin 2 (left) to minus. Pin 1 of the “SAOH” is not connected to plus.
(see next posts)
No, that’s the same as ground, so B+ and LDO output are above that. (=positive LDO)
But make sure pin 3 (top, as in the diagram above) is connected to the battery +.
Pin 3 (top) is not (directly) connected to plus. No ‘beep’ on de DMM.
It’s very hard to follow the traces with my DMM, the probe pins are too big and blunt and i suspect it is indeed more than 2 layers PCB, because visually many traces stop at a through hole.
Is it possible that the plus gets switched by the µC, so that it only works when the light is on?
Could the “SAOH” have something to do with the ramping between modes perhaps?
Or maybe with switching from linear to boost (because it’s also quite bright with a CR123A)?