Component stripped from driver.. Klarus Mi1C

The through holes on the other side are under the inductor.
So i can’t see where it goes.
I will upload a picture of the other side.

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.

Seiko / Ablic S-1206 is a match for SAOx: a 2.5V LDO.
Bottom left pin = ground would fit too.

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).

Okay, now we’re getting somewhere.
Thanks! :+1:

what does LDO mean and what does it do?
EDIT: I see it’s a Voltage Regulator.

Low-dropout_regulator

This board might have more than 2 layers so the through holes could have a purpose.

Yeah, that crossed my mind too, but i can’t see a hint of another layer…
But it would make sense.

Is this the same?

or

If not, can someone help me find one?

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.

I’d try and get a replacement somewhere that doesn’t take a month to ship though.
e.g. https://www.conrad.nl/p/microchip-technology-mcp1700t-2502ett-pmic-voltage-regulator-linear-ldo-positief-vast-sot-23-3-651410
or maybe you have a local shop.

PS: I think Arrow has free shipping right now, might be the fastest & cheapest option of all

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)

wait, i’ll do some testing, be right back.

Oh, there’s some confusion here.

The S-1206 datasheet has pin 1 on top, but common SOT-23 nomenclature has it at bottom left:

Uhm… so… pin 1 (bottom left) of “SAOH” is connected to minus.
So it’s not a positive LDO, correct?

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)?

I really don’t know… :weary:

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?

Dang… This was not a cheap light…

Where did you get this information?

I checked: in my case the damage is done to 31VGp….I tried searching for that code but nothing comes out. Any idea what would that be?

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.

Is this a true CC (no PWM) light? If yes, then I suspect it’s an op amp. The number of discrete passives around it also point to “opamp”.

Unfortunately there’s 2 different pinout variants that most opamps in these packages follow:

One way to tell: desolder the sense resistor and check which pin has a resistance of a a few 10kR (or zero) to LED- ; that’s IN+

(no guarantees, but most CC drivers use the opamp in the same way it seems)

Thanks kikkoman, will check the next time I pick up the iron. :slight_smile: