Inside the Omron D2FC-F-7N microswitch

When my ancient Logitech G500 mouse stopped working properly, I followed these helpful instructions to bring it back to life. Now I know more than I ever wanted to know about the mechanics inside the Omron D2FC-F-7N microswitch.

Here’s a short video I made showing how it should work:

“10M” stands for 10 million operations. There’s apparently also a 20M version.

This is a photo of a working switch:

Working Omron D2FC-F-7N microswitch
The purple arrow points at the contact area that may require cleaning (opposite side as well). You do not necessarily have to remove the leaf spring to do this (I recommend leaving it in place). The green arrows point at the notches mentioned in the article linked above.

The following switches will not work as the leaf spring is not positioned correctly in one of the notches:

Omron DSFC-F-7N defective microswitch
Omron DSFC-F-7N defective microswitch
This one is particularly tricky as it is impossible to see the problem with the naked eye (it looks fine but should be in the notch above).

I recommend opening the switch from this side (compare label on your switch for orientation):

Opening Omron DSFC-F-7N microswitch
Just like me, you will most likely bend and dislocate the spring if you open the switch from the other end.

Finally, a photo with my finger shows why these are called microswitches (actually Omron uses the term “Ultra Sub Miniature Basic Switch”):

Omron DSFC-F-7N microswitch size
If you don’t like working with tiny parts you might be better off getting a new mouse.

Disclaimer: If your mouse has been in use for several years, you should seriously consider buying a replacement switch. I believe you could desolder the switch from the top by cutting it into pieces first (the plastic is rather soft). Replacements don’t seem to be available from electronic components distributors but are sold on (affiliate link).

I was only able to repair my mouse because I had another broken one from which I stole a leaf spring (from the less-used right switch). The original spring of the left switch in my mouse was badly deformed. Unfortunately I can’t show you any pictures because it flew away when I tried to bend it.

13 thoughts on “Inside the Omron D2FC-F-7N microswitch”

  1. I was able to open the left click switch on my no longer clicking Logitech TrackMan, remove the “reed”, clean out what looked to be dust(?) and then put it back together. It now clicks properly. On my “machine gun” clicking M570 wireless trackball, I tried the same procedure, and it still does not work properly. I’m sure I could get it working if I spent more time, but I decided to just order 6 brand new Omron switches for 6$ from Amazon.

  2. I’ve just spent two hours trying to refit one of these microswitch springs (Logitech M570 mouse) after disturbing it whilst cleaning the contacts and have given up, followed by an order on Amazon for replacement switches. Hopefully a straightforward swap will be much easier. An item worth keeping a few spares of as they seem to be used in many different mice.

  3. De-solder and re-solder a new mouse micro switch. Then it’ll be like new. I wouldn’t bother with re-jigging the insides of the switch.

  4. hey fellow trackballers! don’t try these meticiluous methods
    just apply concact cleaner spray on top of the switch

    1. …which will ONLY fix the problem for a short time…it WILL start acting up again soon…once the coatings on those relays get old and corroded it will not “refurbish” for much more than a few months…just replace the switch for a CERTAIN long fix.

  5. nice set of photos. I’m tempted to try the disassemble option myself as having desoldered and resoldered a replacement, it’s a tricky job and it’s easy to mess up nearby components depending on the pcb layout.

  6. Dude, youโ€˜re a legend. I smashed my mouse on the floor and the switch acted weird like no spring. I openened it and managed to bring everything back in position with your instructions and now it works like new.

  7. My mouse works again!!! Thanks for the pics and explanation! My M570 was double-clicking on its own, but when I took it apart I wasn’t setup on my table and obviously (in hindsight) it fell apart and I didn’t know how to put it back together. I tried peeking into the other button, but was scared to disassemble too far in fear of doing the same to it. The button seems to be behaving now, so I think I can count the last hour of screwing around as a success! It feels worth it, even though monetarily I should have just paid the $6 on Amazon for a pack of new buttons ๐Ÿ˜›

  8. Thank you so much for this
    I fixed my logitech g403 hero not registering left click by adjusting the spring. The images helps a lot

  9. Thank you for your outstanding macro pictures of the switch and clear explanations, which enabled me to repair my Logitech M720. When I opened the switch, the spring was not quite in place and fell off. So much for avoiding its removal! But that was, in fact, the root of the problem. Putting it back correctly in place was fairly easy (thanks to your article!) and it completely resolved the issue. Thank you again!

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.