Bally S5500 Error 24

[busabrent]

Good Evening Everyone, I picked up my first slot machine a Bally's Sevens. It had an error 81 and i replaced the battery and did a reset with the jumper and holding the two buttons.
now it gives an error 24. the coin comparitor light is not green but when i press the test button it lights up. Should i replace the coin comparitor?

[Badbaud]

Is the coin comparator switch in the up position?
It must be up to turn on the coin comparator.

[busabrent]

not sure where that is located?

[sixcardmark]

There is a toggle switch on front of MPU tray.

[busabrent]

yes i have the switch on, in both on and off it still gives the same code

[Sunrise Side]

24 is reverse coin.  Remove comparitor and check the path/guide which the coins go through at the coin optics. Reseat the harness at the coin optics board. May have to disassemble coin optics and clean the optics and prism. May be a bad optics board. Make sure the lower part of the comparitor bracket alignment hole is mated with the pin/tab. This aligns the comparitor to the coin guide on the  optics assembly.

[busabrent]

that was it! the optics looked clean but when i opened it was covered in dirt plus a dust bunny got in that black plastic somehow