Amiga 500 tank mouse malfunctioning

[ramonsmits]

Hi all,

I've bought a second hand A500. The unit is in reasonable condition but the mouse is not working correctly. I first thought that maybe the port is broken but connecting a joystick given no issue.

I recently bought an Atari joystick compatible USB adapter and it has the ability to flash the adapter with a firmware to connect an Amiga mouse as a regular HID mouse. The amiga mouse behaves exactly the same so the conclusion is that the mouse must be faulty

What does work

* Left button
* Right button
* Horizontal movement (left/right movement)

What does NOT work

* Vertical movement (up/down)



Is this a common defect? Any idea how I could troubleshoot this to fix it myself? Can I measure certain pins for voltage/resistance?


--Ramon

[bebek]

Check cable continuity, one of lines is possibly broken

[TomCrazy]

Test the same Amiga motherboard with another mouse (not joystick) in the same port. The 9 pin Dsub has different pins for joystick and mouse, so just testing with a joystick is not reliable. You need to verify motherboard functionality with another mouse to start with.
If the motherboard is fine, proceed with checking the mouse.

Open up the mouse and look through a camera to verify that all LEDs are lit when the mouse is connected to the Amiga. If they are, check all wires for any possible breaks. Use a multimeter set to continuity check.

[Jope]

Also check to see that the spring loaded tension roller in the corner hasn't jammed in its hole.. It should be pressing the ball snugly onto the quadrature rollers.

[willbloke]

Or drop the ball out and tweek the roller with your finger !

From memory the Amiga mouse is pretty dumb , so there shouldn't be much to go wrong other than quarter century old wiring !

[Jope]

The tension roller used to be the #1 cause of trouble (it often jams if you drop the mouse), button switches #2 and unfortunately broken cables #3. :-/

[ramonsmits]

It seems that the cable is fine after testing the wires although the resistance on the solder is about 30-50 Ohm on pins 1-5 and less then 10 on pins 6-9

I do not have a spare amiga mouse or another amiga to test :-)

When I connect a joystick and rotating the mouse moves the pointer diagonally.

Testing the roller directly with my fingers didn't work. Also, as I said, the mouse behaves the same with the USB retro adapter. If the port on the Amiga would be faulty then the mouse should work ok via the adapter on the pc.


Look through a camera to see broken leds? How to I do that? Going to test this with my mobile camera.

[ramonsmits]

I see 4 small purple dots through my mobile camera so I guess the leds are working.