Mouse repair : Can't move cursor, but clicks work and wheel too

[komrad2236]

Hi everyone.

I am trying to repair a mouse, its Microsoft IntelliMouse Explorer 3.0

Clicks work, scroll wheel too.
But cursor wont move.

Here is a video of the mouse : 
https://youtu.be/DHqglwso-70?t=49

The reason I am showing you this particular moment in the video is because the guy flips the mouse and on the bottom side you can see that a RED LED is present in the middle and its glowing.

I want to report that in my situation, this LED does not emit light at all, which should mean its broken and I need to replace it.

So I have two questions :

1.How can I find appropriate replacement LED ? (as in, how can I be sure I am using compatible LED ?)
I disassembled the mouse and inside I can see that the LED is transparent and its supposed to emit red light.

2.I noticed some mice do not emit any light underneath, whats the difference and how are they called ?(mouse that emits red light underneath vs the one that does not)

[Haenk]

To my understanding, there is a complex image sensor doing the tracking work. So simply replacing a LED is not going to work.

[tunk]

Open it and if it has just one chip; since the buttons
works, I'd guess the chip (including image sensor) is ok.
If you have another old mouse, you could transplant the
LED and see if it works.

[wasedadoc]

Before you try to change the LED, measure the voltage across it.

If there is no or very low voltage the LED is not the problem.

If there is a reasonable voltage, tack another LED (any red one) across the existing one.  If that added LED lights then the mouse LED is almost certainly faulty.

[Gyro]

Irrc, the LED is driven by an output from the image sensor, dim until it detects movement and then bright for precise imaging. On some models the LED is driven directly by the output pin and on others, via a driver transistor. A few more things to check before condemning the LED completely. Wasedadoc's suggestions should eliminate the LED anyway (unless it has failed short).

Regarding question 2, the mice that do not emit light (and have no ball), I think these probably use an IR LED.

[komrad2236]

Open it and if it has just one chip; since the buttons
works, I'd guess the chip (including image sensor) is ok.
If you have another old mouse, you could transplant the
LED and see if it works.

Thanks.

I did have a spare mouse(very old and not going to be used) so I transplanted the LED and fixed the mouse.

I was actually able to repair two mice like this just now. 


I simply de-soldered the LED, tested it with a simple multimeter set to continuity and it did not light up at all.
Replaced it with spare LED, and mouse works like brand new.

Thanks again

[komrad2236]

Irrc, the LED is driven by an output from the image sensor, dim until it detects movement and then bright for precise imaging. On some models the LED is driven directly by the output pin and on others, via a driver transistor. A few more things to check before condemning the LED completely. Wasedadoc's suggestions should eliminate the LED anyway (unless it has failed short).

Regarding question 2, the mice that do not emit light (and have no ball), I think these probably use an IR LED.

I think desoldering the LED and just testing it is the fastest way to tell so I did just that. 
Actually, since I had the spare mouse that worked, even while LED is still on the board I was able to test it and it does light up(when testing with multimeter).


On to Q2, I learned that most optical mice emit red light underneath, they use transparent 5mm led that emits red light because I guess red light works the best.
Like you said, some mice do dim until movement is detected, most likely this extends the LEDs life too, so good feature.

I also have one mouse, which I will try to fix next (Razer deathadder) which is optical mouse and for some reason uses purple light LED, which can not be seen by naked eye, you have to look at it trough your smartphones camera.

And yes, finally there is IR mouse.
I have one too, underneath there is a laser warning sticker.

 

[Gyro]

I was actually able to repair two mice like this just now.

Good to know. 

I also have one mouse, which I will try to fix next (Razer deathadder) which is optical mouse and for some reason uses purple light LED, which can not be seen by naked eye, you have to look at it trough your smartphones camera.

Ah, that does sound like an IR LED one. Digital cameras have an IR filter but enough leaks through from a bright LED to still show, albeit with a funny colour. Compare it with the image from an IR remote control to confirm.

And yes, finally there is IR mouse.
I have one too, underneath there is a laser warning sticker.

Quite a collection! It presumably uses coherent laser light to achieve higher resolution than the random light from an LED. If it's IR then you might see a very dull red glow but beware that this is you retina reacting to the very bright IR source! Use the phone camera for safety.