One or two screws under the half circle glide pad
Can't remember if there's a screw under the line glide pad.

Yes should be screw or screws under the half circle pad, most have tabs near the cord IIRC so when you unscrew, gently lift top at an angle from the screw side or else you could break the tabs.

Ah, I pressed around there, usually I feel the holes sinking in but not this time. Thanks!

Well I found the screws and they were NOT under the half circle pad, but under the model sticker. That's all sticky things removed, I hope I can replace them 🙁

Now the problem is, I cleaned this as much as I can, but I still get a jumpy cursor when I go too fast. Works well when going slow.
The innards look like this:

I never quite seen a mouse like this so I have no idea what to do. Seems like the diodes are inside those potentiometer-looking packages.
I blew air in them (you can remove the black back) and used some contact cleaner fluid too, but they still work the same way. I cannot physically reach the leds, without destroying the package.

Could it be something else causing this issue?

Thanks for the info ! Does it jump in both serial and ps2 modes ?

Horun wrote on 2022-06-12, 23:55:

Thanks for the info ! Does it jump in both serial and ps2 modes ?

Interesting. I don't have a serial to PS/2 adapter, so I cannot know if it does it in serial mode only.
Also, I should try it in another computer too, while we're at it.

Still trying to figure this one out, don't know if I want to spend $10 in a ps/2 serial adapter. And most of the ones I find are the wrong genders anyway.

What do you mean by "jumpy cursor"? If the cursor moves in the correct direction, but with larger steps when you move it quickly, that's normal for a serial mouse due to the slower update rate. It will seem choppy compared to a USB mouse.

Plasma wrote on 2022-06-15, 23:07:

What do you mean by "jumpy cursor"? If the cursor moves in the correct direction, but with larger steps when you move it quickly, that's normal for a serial mouse due to the slower update rate. It will seem choppy compared to a USB mouse.

I meant that if you're moving to the right, it will go left every now and then. How much left, depends on how fast I move it. that's "jumpy".

I tried it in another machine and it seemed to work fine. maybe it was a computer problem on the serial port?

What computer and what software are you using when the mouse sometimes does this jumpy behaviour ?