A500 Tank Mouse vertical movement issue
 

Mouse issue:

Left and right is fine. (dodgy at first and improved after blowing the wheel)

Both buttons are fine.

Up and down doesn't work.

Tested a known good mouse on my A500 and that worked fine (phew).

Took a can of compressed air to the open mouse. Didn't seem to make any difference...however....if I spray it while plugged in (yes I did this), the wheel spins fast and THAT gives up and down movement.

So now after much spraying and rolling, I some "some" up and down movement but very little and very sporadic.

Ideas? I really want to try and resurrect this mouse as it's the original from this pack and in excellent condition cosmetically.

The situation "seems" to improve the more I hit it with spray but I'm wondering if a known electrical fault should be looked at?

Additional:
Yes all the simplest things were tried first.

Old habits die hard. The VERY first thing I did was pull out the ball and inspect the condition (almost spotless) and move the rollers directly.

Most testing since then has been done with mouse open, turning the wheels directly.

Adding this info to the OP

The cable might have an internal break, usually near where it enters the mouse.

This should be the schematic for the tank mouse:

(http://www.pavouk.org/hw/en_amigamouse.html)

http://www.pavouk.org/hw/amigamouse.png

If the left/right directions - i.e. (H)orizontal is working, but there are issue with the up/down directions - i.e. (V)ertical, that could an issue with:

1. The pins/cable for the V and VQ signals - i.e. pins 1 and 3.
2. The pull up resistors for the V and VQ signals.
3. The logic chip LM339 (Quad differential comparator).
4. The pull down resistors for V and VQ inputs to the LM339.
5. The V optical sender and receiver components.

So you should check these traces/pins/components.

Photoresistors can get old and the temperature decrease from spraying them could be making them perform better.

Agreed. I also had an issue with the Photo resistors / interrupters.

I have one of these mice in a drawer with a very similar fault. I've tested everything and can confirm in my case anyway its the photo resistors.

Worth checking your cable first though just in case.

Cheers guys. Have pulled out my multimeter and will have a poke around inside the mouse again tomorrow.

I had the problem in my tank mouse. One of the optical sensors was out of spec, which caused the IC chip receive the wrong voltage on one of the inputs.
I solved it by installing resistor in parallel to one of the input.

Cheers mate. I saw another thread on the topic where someone replaced the bank of 5 resistors but I can't for the life of me find it now.

What ohm resistor did you use and where did you fit it?

Have a look at this blog post regarding replacing the phototransistors:

https://www.tsb.space/knowledge-base...se-fix-x-axis/

Ah fantastic. Thanks!

Probably a very silly question BUT did you thoroughly clean both weighted ball and the physical rod(s) and roller it turns against in the mouse ball cavity?

These old mechanical ball mice are notorious for having the rods that turn the interrupter wheels jam against the rotating ball due to an uneven build up of gunk on these rods. you can use Isopropyl alcohol and cotton buds to clean stubborn gunk off the ball, the roller, and the two x-y rods.

Having up and down work when compressed air is rotating the interrupter wheel indicates that your wired connections are probably fine.

Up and down should work perfectly even by just rubbing the tip of your finger against the roller in the mouse ball cavity. I'm assuming the 005AGIMA tried this already?

A common fault with tank mice is, that the pressure roller in the corner gets jammed and no longer presses the ball against the rollers reliably. Usually happens if the mouse gets dropped. Easy enough to un-jam, but again I'm assuming the easy stuff has been tried out already.

Hi guys. Yes all the simplest things were tried first.

Old habits die hard. The VERY first thing I did was pull out the ball and inspect the condition (almost spotless) and move the rollers directly.

Most testing since then has been done with mouse open, turning the wheels directly.

Adding this info to the OP

Thanks again for THIS LINK!

Purchased a pack of 10 OSRAM LPT 80 A phototransistors from RS Components online. Delivered next day for free (as in delivery was free) for about $11.

Installed 2 for the Y axis and the mouse is good as new. PERFECT!!!!!

Very very happy.

Well done for fixing it! :great

Video of the mouse symptoms, fix, and result.

This is in no way a "how to" but hopefully some future user will find some of it helpful.
https://www.youtube.com/watch?v=XUjqIohxCrA

Timecodes:
00:00 Intro/symptoms.
01:38 Troubleshooting - try another mouse.
02:40 Troubleshooting - compressed air clean.
07:19 Troubleshooting - resistors checked / looking at IR Diodes.
09:29 Swapping phototransistors including getting to them by opening the clips.
18:08 Testing and the result

Sorry, I did not enable the notification for this thread and missed your question. My fix would not work for you if your diode was the other one.

Nice job on fixing it properly. I did it the hard way, not correct way, and with parts I had on hand.

Hope this doesn't qualify as a thread hijack but...may I ask whether the A1000 tank mouse has the same parts as the A500 one?

I'm having issues with either H or V (maybe both? it's been a while) and since it is very difficult and expensive to source an original replacement I would like to repair this one if possible.

They are the same mice as the very early A500 mice with a sliding ball door. The ones with a rotating door are subtly different.