S plus coin-in error

[yerigh]

IGT S+ that keeps giving me a 21 error code and I cant figure it out. Before I actually replace the comparitor I have been checking for power because I am not getting anything happen on the optical coin sensor below the comparitor.
On the wire harness I get 12.3 volts ac. From what I have read, it should be 24 volts ac or 13 volts dc.
Let me know what you think?

[shortrackskater]

I'm moving this to the S plus section because your CC may be fine.
Did you try simply opening and closing the door, with power on?

[sixcardmark]

Code 21 is coming from the optics board, not the CC.

[Stayouttadabunker]

I've attached for you, a drawing below that I have of the S+ coin comparitor pinouts.
Pay especially close attention to the voltage that you're reading with the multimeter on the 4th pin.

However, your code [21] would be coming from the coin-in optics board that's located directly underneath the CC, as sixcardmark is referring to.
Check to make sure that the ground wire has continuity from the main door harness connector to the pin on the Molex housing at the coin-in optics board header.
If the ground wire is broken inside of the wire covering near the pin end, you would not be able to see the break.
This is why we use multimeters to check for continuity from pin-to-pin.
A break there on the ground wire, would shoot out the [21] code onto the display.