FIXED: Atari 520STFM Mouse Issue, all directions work except down which goes up.

[Ally]

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!

Atari 520STFM Keyboard image after unsuccessful fix for Mouse Issue

20211218_135806.jpg (287.07 KiB) Viewed 2955 times

Atari 520STFM Keyboard image after successful fix for Mouse Issue

20211218_170032.jpg (164.58 KiB) Viewed 2912 times

[fill-ST]

Have you tried turning it on and off Ally

[rubber_jonnie]

Does alt+the arrow keys work ok?

[Ally]

Does alt+the arrow keys work ok?

Yes, the alt-arrow keys work perfectly!

[Ally]

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

[Darklord]

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?

[derkom]

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.

[Ally]

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!