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)?
By the way, Conrad is expensive and also charges shipping, making 1 of those LDO’s twice as expensive as 10 pcs from ebay…
I could fill my cart with € 30.— of stuff and get free shipping, but everything is expensive…
I saw a Cree XM-L2 for € 18.— for example…
Carclo triple optics are quite cheap though at 1.76 (or something).
So, kikkoman, should i just order from ebay and hope it’s what i need, pray and solder it on?
Or do you think i could ask Klarus for info?
I think I searched at LCSC (they have a nice little picture of the actual part) for SOT-23 LDOs and one with a matching marking came up (SAxx), then had a look at the datasheet. http://chip.tomsk.ru/chip/chipdoc.nsf/vc1!readform&view=smd&cat=A&start=1&count=500 is also very useful, it’s the most comprehensive list on the net as far as I can tell.
You should also check against the bottom right pin of D19HJ (which I suspect is for polarity protection, maybe a p-FET).
Since it’s an e-switch driver the µC needs to be constantly powered and that’s usually done with an LDO. Which would also explain the 2 decoupling caps to GND.
But yes it _might _be something else like a voltage supervisor that’s why we need to figure out where its input & output go.
The TPS63020 is a buck/boost converter that switches between modes automatically.
By the way, Jerommel, have you tried reattaching the part with some flux and big fat solder blobs? Looks like there’s still some of the pins left that it just might work. Maybe dig a little into the package with an x-acto knife to expose the lead some more
Probably the lot number, the last 1 or 2 digits often are just that. (Seiko datasheet matches too)
From LCSC: - I’m 98% sure this is the part used. (Which doesn’t mean you have to replace with that exact part, any LDO with similar specs and same pinout will do fine.)
I hope you will be able to find the right part too.
Please report back here if you do, so people will be able to find the parts when they make the same mistake as we did:
Sticking the needle nose pliers too deep in the holes of the driver retainer ring… :person_facepalming:
Oh boy these parts are so small…will I be even able to measure the pads with my probes? Not sure. Not today, I soldered the centering ring to a pad while unsoldering a lead, this is not a good day to try desoldering a component off this board.
At least I did a sanity check: I did not fry the LED by my clumsiness, it’s the driver.