I’m a big fan of Logitech mice, or at least was until a few days ago. My wireless Logitech M705 started to behave strangely: Pressing down the left mouse button resulted in multiple clicks (i.e. double-clicking) and dragging became impossible due to random interruptions when holding down the button.
Without a warranty (which had expired three months ago) I did not feel guilty when opening the mouse to look for the cause. The culprit was quickly found: the microswitch of the left mouse button. Luckily, I had spare microswitches as I’m currently playing around with the optical sensors from other spare/defective mice. I will cover this in another post. To come to the point: after replacing the microswitch, the mouse works again as usual. I’ve made a few photos (a picture is worth a thousand words 
) to help others during disassembly of the housing. Screws are marked red, and I have also marked (in yellow) two tiny springs that can easily be lost.
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- The housing is held together by five screws
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- Two screws left and right of the mouse wheel
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- A small bolt holds the mouse wheel
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- Two screws under the mouse wheel
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- Some spare microswitches from old mice
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- After exchanging the defective microswitch
This fix has a bad aftertaste: at least in Germany, there is much talk about “planned obsolescence”, and I’m wondering if Logitech (and other manufacturers) use cheap microswitches that only survive a certain number of clicks. Especially after my mouse showed the previously mentioned defect so soon after the expiry of the warranty… On the other hand Logitech kept its promise regarding the battery life – I’m still using the first set.
Update: Just as a brief clarification, after I got some feedback on the M705. (Apparently several users have had similar experiences.) Logitech uses Omron switches that actually seem to be pretty good. So I want to point to a post from Ralf who recommends to first try resoldering the joints. If that doesn’t help an exchange might be the best option.
Nice post. I’ve use various mice since the early 90s both PCs and Mac and the only double click problems I encountered is the Logitech mice I bought one year and a half ago.
I have a problem developing with my m705 left click and I’m not sure if I should just ditch the unit or try cleaning it once again. I don’t have any micro-switches and honestly the lack of drag-drop + constant double clicking is getting rather annoying and quickly.
Microswitches are pretty cheap (less than one Euro) and standardized, but desoldering them from a multilayer board can be quite unpleasant… I’d send you one of mine but I think this just as expensive as buying a new one.
Before throwing the mouse away, I’d at least try to repair it. Maybe you could take the mouse apart and first try to carefully open the microswitch itself to clean the contacts. If that fails, i.e. the microswitch case cracks, you could still try to desolder it.
Dear Kai,
thank you so much for this article. I just had the very same symptoms with my M705.
In my case, it wasn’t even necessary to change the micro switch. All I needed to do was to re-solder the three solders that hold SW1 in place. That did it for me.
The reason for the failure was only a bad / cold solder. Such a failure is very common for parts that are under heavy mechanical stress, so I find it quite likely that your problem (and that of other users) was also caused by a bad solder. If this was true in your case, you actually fixed it by de-soldering SW1 and inserting another switch – witch fixed the alleged bad solder as well.
@Marty: You should give this a try, no spare parts needed.
At least in my case, it couldn’t have been a case of planned obselescence, because nobody can calculate when exactly a bad solder is going to break. In my case, the failure happened after less than two years, which is well within Logitech’s guarantee period of 3 years for the M705 (Despite of that, I preferred to fix the problem by myself). They would only harm themselves if they built in such a quickly developing problem.
Hi Ralf,
thanks for your comment. I support your recommendation to at least check the solder joints, after this has also been a problem for me in other cases. Resoldering the joints is easier than exchanging (especially desoldering the new lead-free solder on multilayer boards can be a PITA).
In this case I had decided to exchange the micro switch as I had spare ones lying around… Kai
Hi,
I have a similar problem with my Microsoft Wireless mouse. Left Click button is not working. all other functions seems to be working. that is, right click, center click, scroll wheel etc…
It looks like I need to change the micro switch for my left click button issue… Is the micro switch you have shown in the picture is 2-pin micro switch? or 3-pin micro switch? For me, it looks like I need 2 pin micro switch for this Microsoft mouse.
My Mouse model: Microsoft Explorer 2.0
Model No: 1007
Appreciate your time.
Thanks,
Antony
Hi Antony,
I’m not familiar with that type of mouse and a quick web search for its interior was not helpful either.
In my case common 3-pin micro switches were installed, but only two of the pins were used (i.e. it wasn’t used as a changing switch) if I remember correctly. I have not yet seen 2-pin micro switches, so maybe the ones in your case are manually modified (with the third pin removed)? I would recheck that if I were you.
Best, Kai
Hey, i found this article very nice. I’ve experienced same problem, quick search landed me here. I’ve had cheap mice that have had defective switch, then replaced the faulty switch with new one found in local market. Apparently the new switch has lower quality, LOL so the click feel so clacky hard and the lifetime ended so quickly.
For my m705 instead of replacing the switch, i resoldered those switch pins on the pcb. I found that the faulty were not in the switch but in soldering tin quality (brittle and pores), seems like the problem was in PCBA line.
This post explains how to restore the spring in the switch, which supposedly fixes the problem.
Good article!
Now I have my M705 as new one, zero cost!
Thank you, you really helped me with pictures hidden screws under the battery.
Steve
Hi
My mouse fixed just by “Emptying Capacitors” !!!!!!!!!!!!!
1.Remove batteries
2.click all buttons repeatedly for 30 seconds
http://forums.logitech.com/t5/Mice-and-Pointing-Devices/Erratic-MX-performance-mouse-issues/m-p/711968
Thank you for the excellent documentation you have provided for disassembling the M705. I was tearing my hair out trying to get it open without success. You showed me there are two more screws hidden under the sticker in the battery compartment.
My scroll wheel was stuck and would no longer work as a middle button. I simply needed to open it up to free it, and it works fine now.
However, the plastic pad on the bottom of the mouse will never be the same again, after having to remove it to access the two screws. I wonder of Logitech can supply replacement adhesive pads?
I had the same button problem. I contacted Logitech customer service (mouse was less than one year old), explained what’s wrong and they sent me a replacement mouse cost-free. I didn’t even need to return the defective mouse.
Hi Christian!
Thanks so much for this article. I couldn’t find the instructions on how to dismantle the M750 anywhere else.
Can you remember, if the microswitches used for the two lateral buttons (those that are often used to go back and forward in a browser) are the same as the ones for left/right clicking? It’s not quite visible from your photos.
I dropped the mouse and damaged one of them, but I don’t think they’d replace the mouse in terms of guarantee. It’s also quicker if I replace them myself. Then again, I don’t want to loose the guarantee by dismantling the mouse just to have a look, in case I needed it for anything else.
Can you help?
Thanks!