Roland Alpha Juno 2
Mod-wheel / bender
If the mod-wheel has no hearable effect, but is movable and snapping towards the middle, the small black hexagon screw is eventually not tightened. Just tighten that screw and test the bender again.
If then the bender has a hearable effect, but gets stuck or moves to its middle very slowly, the cause can be a stuck axis of the pot. To solve this, open the hexagon screw again, and also other screws so you can disassemble the bender parts. Put a suitable contact spray (I've used WD40) onto the axis of the pot. Turn the axis a minute or so back and forth until it's getting at least a bit more movable. After some hours the contact spray will become even more distributed by itself between the axis and the pot housing, now the pot will be easy movable.
Leaked caps
In my case, there was cracking sound and suddenly no sound at all, because of leaked caps C11 and C12: They damaged the conductor beneath. Remove the faulty caps, check the conductor, and replace the caps with same capacity and same voltage or higher voltage.
