Almost got it, but now a sticky mouse on A500?

[ferix]

Follow these steps (if one fails, continue to the next):

1. Check power. A faulty 5v line can get your A500 crazy.
2. Reseat de CIA (the one that is close to the joystick and mouse ports).
3. Swap the CIAs
4. Reseat DENISE chip (It, or she, drives the mouse signals).
5. Replace EMI400 and EMI401 (check value on schematics, It changes from version to version).
6. Replace the 74LS157 chip (U15?)

If your mouse buttons work well, you can skip steps 2 an 3.
I bet It's the 74LS157

Good luck!!!

[ferix]

I will give the DENISE a reseat next since I have a PLCC tool around here somewhere.

AFAIK DENISE has DIL packaging on A500, not PLCC...
Only AGNUS has PLCC packaging, and It (or she) has nothing to do with the mouse or joystick.

[ferix]

[..] no change in the mouse behavior.

Next logical step is to replace EMI400 and EMI401, but I'm pretty sure the problem is U15 (74LS157).