Amiga 2000 Faulty when mouse pulled in

[mechy]

Hi,
This might sound strange. I have an Amiga 2000 which boots ok from FDD and HDD and keyboard works ok, but when I plug in the mouse the displayed image goes mono and shifts to the left and the mouse doesn't work. I've swapped out the both 8520 from a working Amiga 500. I've checked for dry solder joints etc. All with no joy.
Any pointers?
Thanks.

did you try another mouse?

mech

[mechy]

No the last time I fired it up a week ago it was working. I wasn't aware of PC mice causing damage. But I had just used th Amiga mouse. I hooked up a multimeter to the +5V and only got 2.3. Not sure if i will see 5 when there is no load. Tomorrow night I'll hook it up to the Amiga 500 and see what I should get.

Some A2000's had small plastic pads on the bottom of the motherboard to keep the pins on the mouse port from shorting to the case as i recall, some didn't. Maybe this is the case with yours.

Mech