Amiga 1200 mouse issues, I think the logic board is fried!

[BillHarrison]

Well, the mouse works in another unit, but when plugged into the 1200, it only goes left to right, not up and down.  The unit boots fine, but you have no real mouse control.  I know its not the mouse, so it has to be something else.

Anyone know what chip / etc controls this?  I am thinking someone may have plugged in a serial mouse?  And burned something up?

Bill

[Ilwrath]

Maybe... The CIA chips control the mouse ports.  They are noted for being quite fragile.  

Something I might check first, though, would be the port itself.  Maybe you're not getting a good connection on one of the pins?  Bent pin?  Pin loose on mainboard?  Physically examine the traces back from the port a short way.  Notice anything amiss?

Tackle the simple before diving into the complex logic chips.  

[mongo]

Maybe... The CIA chips control the mouse ports. They are noted for being quite fragile.

The CIA chips only control the mouse buttons. Mouse movement is controlled by Denise.

[BillHarrison]

I have cleaned, and checked the pins and connections.  I opened the amiga up, but am totally lost.  I resoldered the port to logic board pins, thinking perhaps it was a cold solder joint (i have ran into this on alot of other electronics) but that did not seem to help.  Everything is surface mount, so I am thinking I may just be stuck buying a new amiga, or atleast a motherboard.  But, if I am going to do all that I am going to get a 4000

[orange]

Is it a standard Amiga mouse?
I once had a weird problem that only Commodore mouse would work, it turned out that some other mouse would take too much current (PSU had bad connection on motherboard).