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:

Inside the Omron D2FC-F-7N Microswitch
“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 Amazon.com (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.

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