Weird problem with Haikelite HT35 and where to get spare parts ?

This Haikelite HT35 is flashlight of my friend which been on the countryside in his father possession… He is very old men, over 80 years old and we don’t know what is happen with flashlight exactly, maybe it fall down on the ground, maybe something other, only we know is that flashlight is worked OK some time ago… Friend give me a flashlight and tell me that it is not working.

I try to turn it on but no response at all, took out cells, and measure them, one have 3.6V, and other have 0.26V, interesting is when I post positive probe to + cell side and negative probe on negative cell side it give me - 0.26V, but when I reverse probes it give me +0.26V, never have this kind of problem when measuring cells. So this cell is damaged, and I have no idea how it happens, only know that cells are used only in this flashlight and no where else, maybe this faulty driver make a problem…

So I continue with the test, put two my cells there and try to turn on flashlight no response at all… Try to bypass tail with wire and turn on like that, I have every time little spark on the flashlight tailcap when try that, so it is not about switch.
Then I desolder a LED with MCPCB and try to test LED, and it was working. So driver is faulty. I don’t know what happens to get to this since flashlight is not in my possession and don’t know also for how long this exist, but only I can assume is that flashlight is fall down and driver was damaged which cause that one cells is drained more than the other and it is destroyed.

The driver is in pill and main question is where to find this driver do order and replace, how to contact Haikelite or where to find it, LED is XHP35 HD, and cells configuration is 2x 26650, about 2000 lm is output.
Second question is what you think cause this problem ?

Haikelite used to have a website, now they only seem to have an Aliexpress store in Russian. They list drivers, but not that one. You may be able to contact them through Aliexpress.

https://aliexpress.ru/store/group/flashlight-parts/4692069_514685248.html

English Ali store here:

https://www.aliexpress.com/store/4692069?spm=a2g0o.store_home.pcShopHead_14156761.0

This driver looks like it would work: https://www.aliexpress.com/item/32975612072.html?spm=2114.12010612.8148356.14.eeb05dddE6a0X0

It's the same size and says it supports 2 26350's (same voltage as 2 26650's) and the XHP35HD. It must be a boost driver because it takes in 6-8V, and the XHP35HD is 12V.

I would still try to ask them first though to be sure It would work with the HT35. Sometimes their specs are iffy.

This is normal when reversing the polarity, gives the same reading for measuring current too. Try it with your other cells and you’ll see.

Thank you for finding the store I will contact them now. But 20$ for driver only is a lot !

You don’t understand me… I know that DMM can check reverse polarity to reveal which is + and which is … But you didn’t read carefully… When I put positive ( + ) probe on positive side ( + ) of the cell, and negative probe ( ) on the negative side of the cell ( - ) I get on my DMM - 0.26V which need to be + 0.26V, and when I swap them it need to be -, but it is reverse than it should be…

It will be clear now :

Ah, I misread that :slight_smile:

No response from Haikelite staff and they read my message about replacement driver, hmm, I’m on my own now.

I found this one : kaidomain

It is 28mm which need to suit here, and it is a boost driver which will be good for XHP35 LED.

But this current will not be enought that light work like before, it is only 1.5 amps as far as I can see. Does anyone know good cheap 28mm driver for XHP35 but with more amps ?

OK, I really need help here.
I order this driver from Kaidomain and replace it…

All is ok, driver is fitting, and almost indentical like original one. Problem is that light is working and not working… So it is not switch problem now it is not driver problem since I replace with new indentical one, so I don’t know what is problem here ??

Video here : VID 20210204 233230 - YouTube

Somethimes I get only spark, somethimes nothing, somethimes works, and somethime spark and works, no rule.
As you can hear first time I touch spark was heard on the video ( boost your speakers it can’t been seen on the video because my position, but it can be heard ).

So what the hell is this, can faulty LED making this problem, does anyone ever have this kind of problem ??

Switch is not problem, I try with couple of different cells, driver is new one, only LED is remain.

Give me your advices, and suggestions, I’m not able to figure it out, unfortunately i do not have another XHP 50 to replace here and try then, so I must order it, and don’t know is this an LED problem or something other which I don’t know what since this started from some time, light working OK for longer time…

How did it work out?

I’m looking through HT35 threads to see if anyone has found a good HOLSTER.

It work out that I don’t know what is about.
I replaced led and driver and still same problem.
Probably there is some kind of short somewhere but I can’t figure out what is happening.

also different cells (and cells work in other 2S lights)?

maybe contact between tube and head?

weird

As I said, cells are not problem.
Driver is replaced, led is replaced, same problem, so something other is not right.
I remember that I found here some similar problem that someone have, so it is not a lone case…

I assume, when you say the batteries are good, you know they are good in series, they have protruding tops, button tops, so you have good contact. Sometimes these lights are made for true button tops, and flat tops even with a protruding top won't be long enough for good contact. I would test that outside the flashlight - get the two cells touched up, like in the tube, and measure voltage to be sure you are seeing ~8 volts when fully charged. Then be sure the springs are compressing when loaded in the flashlight. Basically the circuit is LED, driver, batteries, and interconnections like the springs and wires from LED to driver. Batt- travels from the tail, to the switch, through the tube, then to the driver - check it all out for continuity. Also be sure the switch is working -- dang, almost forgot about it. Check the continuity from OFF position to ON position.

Also check for continuity from the spring to the tube connecting surface. Follow the electric path checking for the basic continuity.

The video of testing the light is really strange behavior. Makes me think it depends on how much pressure you’re applying to the batteries, since you’ve changed components out (which would point to what Tom suggested).