How to convert a multi-mode LED torch to single-mode

0xFFFF on 04/01/2015 - 15:39

How to convert a multi-mode LED torch to single-mode

This is a tutorial will take you through the process of converting a typical Chinese multi-mode (On, Med, Low, Strobe, SOS) LED torch to a standard single-mode (On / Off) torch.
Typically when you purchase a cheap LED torch, you will get extra functions such as 'strobe' and 'SOS' which are very annoying (to me at least). The following may help certain people in disabling these functions while still keeping the special driver circuit to run the LED correctly.
So far I have not come across a LED torch that this procedure has not worked on. Hopefully this is of use to some fellow OzBargainers…

  • Apologies for the poorly written content in advance.
  • I'm not telling you that you should do this to your torch. If you follow this procedure and somehow break your torch or yourself, please post pictures so we can all laugh at learn from you.

Skills & tools required

  • Soldering iron, solder, basic usage skills, etc…
  • 0805 5pF capacitor. I'll explain later.
  • Small screwdriver.
  • Tweezers.
  • Multimeter.
Step 1

Find a torch

Step 2

Disassemble the torch

Step 3

Remove the LED assembly

Step 4

Remove the LED driver PCB from the LED assembly. Usually this is done by inserting a small screwdriver in the hole on the edge of the driver PCB and levering it out (can very from torch to torch).
Torch - LED driver PCB

Step 5

You will need to identify the (usually) only capacitor on the driver PCB. Capacitors are often unlabelled and are brown in color (kind of like a tiny jersey caramel). An SMD capacitor
If you can't easily identify it, try using your multimeter.
What you want to do is replace this capacitor with one of a much lower value. I used a 5pF because that was one of the lowest values I had lying around.
'0805' represents the physical size of the capacitor. The value '5pf' represents its capacity. In this case we want a really small value.

Step 6

Fire up your soldering iron if you have not already done so and carefully remove and replace the existing capacitor.

Step 7

Re-assemble and test!

Finally…

If you've done this to your torch, please let me know if this helped you or not!

Electrical & Electronics

Comments

  • ibfragalot on 04/01/2015 - 18:50

    Thanks for the tutorial. Interesting. I may perform this one day to one of mine.

  • endotherm on 05/01/2015 - 01:15

    So I imagine the way this works, it prevents the driver circuit from cycling to the next mode, and just stays at the first? What I want to do is make it stop at one of the later functions (strobe) and nothing else. Any idea how to do that? http://youtu.be/eksxzLoPSpI?t=1m28s

    • 0xFFFF on 06/01/2015 - 15:56

      Long storey short… yes.
      Your second question is interesting. I tried to find an answer for you online but was unsuccessful. If I had the time I would look in to it for you.
      Chances are that you would have to design and build your own LED driver to suit your application.

  • kibs on 01/03/2015 - 01:13

    Would it not be possible to just jump the contacts where the capacitor was?

  • TheSnyper on 21/06/2019 - 10:03
    +1

    I know this is an old post, but this issue has been p*ssing me off for years. I have found two really easy methods to fix it without any soldering.

    1. Holding the power button on for around 3 seconds, forces the torch to turn on in 'ON' mode (without any flashing and other BS). This works on mine but I've heard not on some.

    or …

    1. Drawing a pencil line on top of the capacitor as described here (http://budgetlightforum.com/node/14342?page=1) This forces the 'memory' capacitor to drain within a few seconds of turning it off so it always starts in the first mode. As long as you don't do too much pencil, you can still select the other modes my clicking quickly to them. This is the method I chose and it works perfect.
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