OK as title says. When I open the coin door the low voltage does not activate. Infact nothing happens.

Things I have tested and tried so far.

joined wires together green/red and White/red and nothing to exclude a faulty switch.

Checked the wpc coin interface board for dry joints, tested the diodes and continuity all ok.

Checked wires from wpc coin interface to wpc CPU board via continuity. ok

Further reading the manual it says u20 pin 17 handles the coin door low voltage switch. I doubt it's a faulty u20 or a row or column would be out. I guess maybe a resistor or diode going from the connector to the u20 chip maybe faulty?

I have not tested from the connector J209 Pin 2 and J207 pin2 to the u20 pin 17 chip.

Before I go any further maybe some of you could give me some ideas.

Thanks for the help in advance.

Kindest regards David

Thanks for the quick reply.

That explains it all. What function does the memory protect switch have and how can you test it's working. Also does it matter which way the wires go seeing it's just a switch?

Thanks again.

Regards David

Thanks Jadziedzic for the easy to understand answer.

Regards David