Is there a jumper for this on A500's too? Whats its location ? What motherboard revs?
Not on my rev 5 and probably not on the others. When upgrading to an ECS Agnus I've had to bend the socket contact for pin 41 to get PAL again. I've soldered a lead to the Agnus pin (on top of the shoulder) and took GND from somewhere else.
Carefully unsoldering the socket pin may also do the trick but you may have to insert some sort of isolation into the hole to reliable inhibit contact - or pull out the contact.
Newer revs may not be grounded on pin 41, so to switch from PAL to NTSC you just solder a switch to the floating pin 41 (do make sure it's really floating though).
