IGT Coin Comparator error code 21

[billinaz]

I havent used our IGT slot machine in a while.

I put coins in the hopper, turned it on and Im getting error 21.

I made sure the comparator is securely plugged in.

There is a quarter in the comparator as well.

I cant seem to clear the error code.  Do these things fail just by non use?

[leapyearguy]

it's not the comparator, it is the optics below. I suspect it is dust or some other type of blockage. clean with qtip or canned air and shut the door.

[billinaz]

OK, I got the encoder out and cleaned the 3 sensors (looked like 3 LEDs) and still get the 21 error......

Should the red LED light on the encoder come on with power to the machine?

[leapyearguy]

are you talking about the led on the comparator? then no, not until the door is closed. if you are refering to the coin in optics there is no light, emitter and detector.

[pvj]

Im Having the same problem and noted two broken clips that hold it in place which I ordered.  My other problem is that the wheels, all 3 are spinning slowly.  My comparator is old and I'm hoping can be upgraded.  I guess I'llpull the eprom if I cant stop the wheels.  IGT Double Diamond Deluxe, set on $1.00 tokens.....

Pressing the micro button on the comparater does not give credit, the comparater has two gray wires,

Wheels still spinning slow, tried to reset with door open,

[pvj]

error code 21 update

I was able to clear my error by removing the motherboard several times and reseating it, along with coin hopper, DBV, coin comparator and cleaning all optics with a q-tip and compressed air.  My wheels quit spinning and the machine returned to normal and started dropping coins (finishing out it's previous payout)  Apparently the coin in error occurred during a pay out thereby killing the DBV and coin accept ability.  As usual, I don't know what the exact fix was but all is back to normal.