Mouse doesn't work on first port

[CodePoet]

Hi,

That isn't a picture of your mainboard (it's from BBOAH) - Thomas is right, it looks like the 5v rail may be hosed.

If you have a multimeter, check between Pin 7 and Pin 8 of both of the ports and see what you get. If joysticks work perfectly on both ports, you can pretty much rule out U202 and the pull-up resistor packs

Here's a link to the schematic, the joyports are on the lower left of page 3: http://www.amigawiki.de/dnl/schematics/A2000_R6.pdf

[CodePoet]

Have you tried removing and re-seating Denise (U201)? The M0V and M0H signals eventually end up on pin 38 and pin 9 of Denise respectively.

Here's a list of parts that /could/ be suspect, starting at the signal side (joystick port):

Pull-up resistor pack RP200 (bottom left)
Pull-down resistor pack RP205 (bottom left)
Feed resistor pack RP204 (bottom left)
Quad multiplexer U202 (bottom left)
Denise IC U201 (bottom middle)

It's a bit odd that both joysticks work perfectly, though. If you have an oscilloscope, you could try looking for a pulsetrain at pin 38 and pin 9 of Denise (while moving the mouse plugged into port one), and comparing it to pins 9 and 12 of U202 to check if there is a break in the signal path between both ICs