Mouse and Joystick problem

[mai]

After 10 years i wanted to set up my Amiga1200 again, the Amiga was stored in the cellar.
Unfortunalety i had and still have problems to get this Amiga fully working.
I had problems with the internal floppy and with the keyboard too, meanwhile
i have solved this problems, replaced internal drive with an external one, after cleaning the motherboard with 70% Alcohol the keyboard works too.
But i am not able to fix this joy/mouse problem.
Description:
Fire and mouse buttons works, but there is no movement of mouse pointer and also joy-directions does not work.
I have noticed, that after a while(loaded workbench) the mouse pointer moves wild for itself without touching the mouse, later it stops again to move.
What could be wrong, any hint/tip?
I have spent so much time to set up my amiga and now this strange issue.

[s2325]

Fire and mouse buttons works, but there is no movement

It can be silly idea but maybe you connected mouse to port 2 and joystick to port 1?

[mai]

Originally Posted by s2325

It can be silly idea but maybe you connected mouse to port 2 and joystick to port 1?

No, i have not swapped mouse and Joystick, i have also tested two mouses, its exactly the same problem - mouse buttons works, but no movement, so its sure, thats not a problem with the mouse itself, its more than likely a problem with the motherboard - unfortunalety.

[mai]

Some more description:
Solder joints of the components 2- 5 were very oxidized.
If i touch (i know its not a good idea) the component 1, then this causes mouse movement.

[rkauer]

Redo the solder on board.

If no go you have a busted Paula, what it's dead easy to spot if you have crackly/silent/noisy audio out.

[Toni Wilen]

Not again this popular myth... Paula has nothing to do with mouse/joystick directions.

Paula: right and middle button, paddle/pot counters.
CIA: left mouse/fire button.
Denise/Lisa: directions/mouse counters.

And finally there is multiplexer chip between Denise/Lisa and joystick ports that is is most common reason for broken joystick/mouse port in A500s.

[mai]

Originally Posted by rkauer

Redo the solder on board.

If no go you have a busted Paula, what it's dead easy to spot if you have crackly/silent/noisy audio out.

Audio Out seems to be ok, i am not able to hear something unusual.

[Toni Wilen]

Check U34 if both port directions are borken and everything else works.
Possible reasons: broken chip, missing voltages, broken connections between U34 and Lisa. (there is only simple serial+clock line connected to Lisa. A500 has 4 lines.)

[mai]

Originally Posted by Toni Wilen

Check U34 if both port directions are borken and everything else works.
Possible reasons: broken chip, missing voltages, broken connections between U34 and Lisa. (there is only simple serial+clock line connected to Lisa. A500 has 4 lines.)

Thanks, can you tell me please, how to check exactly(voltage etc), i have no experiences.
By the way, i know i can simply buy a new motherboard, but i would like to try to repair this board, because if i would buy a new board, then the Amiga would not be the same Amiga with what i had so much fun in the 90s, you probably know what i mean.