exxos's Atari, Amiga & retro forum

EDIT: FIXED.

FIX:
One beautiful clean track was not passing any current at all, found when rechecking continuity. It was so short I bridged it with solder and now the mouse is perfect!
I have attached the closeup showing the bridge!
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Atari 520STFM Mouse Issue, all directions work except down which goes up.

1. I resoldered the ports
2. I checked continuity to the next nearest point
3. After watching a youtube vid I removed the 74LS244N and replaced it with a socket and a new 74LS244N

Sadly the issue remains.

I have tested the mouse and it is not faulty.

A PS2 pad with an adapter in Atari ST Mouse mode functions in exactly the same manner, but I am unsure what to check next.

Suggestions gratefully appreciated!

Thanks in advance!

Have you tried turning it on and off Ally :D

Does alt+the arrow keys work ok?

rubber_jonnie wrote: 18 Dec 2021 14:37 Does alt+the arrow keys work ok?

Yes, the alt-arrow keys work perfectly!

After advice elsewhere I have checked for short between pin 1&2
and can confirm there is no short between them.

This is really way, way out there but...

Are you testing this after booting up from a mass storage device or even
a floppy with software on it?

Only reason I'm asking is, way back in the day, there was a virus that
messed with the mouse on ST's.

I know it's highly unlikely but it helps to rule everything out.... :)

PS Also, are you able to use the mouse on a different ST and see
what it does there? Or use a different mouse on the ST in question?

Darklord wrote: 18 Dec 2021 16:47 Only reason I'm asking is, way back in the day, there was a virus that
messed with the mouse on ST's.

The "mouse inversion virus" was the only virus I actually got infected with on my ST back in the day! Presumably it's not the issue here, as it swapped up and down, rather than switched only down to up.

This is now fixed!

FIX:
One beautiful clean track was not passing any current at all, found when rechecking continuity. It was so short I bridged it with solder and now the mouse is perfect!
I have attached the closeup showing the solder bridge to my orignial post!

Thankyou all for the suggestions!