Author Topic: IGT Slot Machine Error 21 (Read 4797 times)

CaliforniaDreamer · « **on:** November 15, 2020, 05:10:22 PM »

I have a machine Wild Cherry that was working fine until a few days ago. It now gets an error 21 and I have tried everything that I know about to clear it. Cleaned the coin versifier, checked the coin shoot, .. I am not sure the machine type except that is an IGT. Any help would be appreciated. BTW I tried the forum search and could fine nothing except the usual. I attached a photo.

slots4home · « **Reply #1 on:** November 15, 2020, 05:29:43 PM »

Sometimes you cannot clear a 21 by opening and closing the door .You can try by pulling the CMOS chip for 10 seconds and replace then you get the 61 and clear from there. If it comes back you may need to replace your optics.

CaliforniaDreamer · « **Reply #2 on:** November 15, 2020, 06:01:30 PM »

Thank you, I will try it however the error 61 requires me to press the self test switch and not sure what that is. I have a key switch on the outside of the machine, is that the self test switch?

Ken · « **Reply #3 on:** November 15, 2020, 06:12:37 PM »

21 indicates the coin in optics is faulting. It's below the coin acceptor left side and you should see a small white (usually) ribbon cable on it. That's the optics.

slots4home · « **Reply #4 on:** November 15, 2020, 06:17:02 PM »

The self test switch is either right next to the on off switch or behind the on off switch. So after the 61 hold the self test switch until you get a 61-1 code then close all the doors and turn the reset key

CaliforniaDreamer · « **Reply #5 on:** November 15, 2020, 10:30:53 PM »

Yes that is the unit that has the photo cells and light source that I cleaned. Do you know what color the light sources are and if I should be able to see then?

CaliforniaDreamer · « **Reply #6 on:** November 15, 2020, 10:37:16 PM »

Thank you much, you have been very helpful. I will check that out.

jay · « **Reply #7 on:** November 16, 2020, 08:11:10 AM »

You might want to check out Ricks FAQs on the main page.
He has outlined most of the major error codes, how to clear them etc.
Its easy reading and a wealth of knowledge.

jay · « **Reply #8 on:** November 16, 2020, 08:47:44 AM »

The light is infared so not visible to the naked eye, and it pulses in a specific pattern so it can't easily be mimicked by a light pen. The intent is to prevent cheaters from opening the machine and bypassing the security mechanisms.

Although invisible to the naked eye, the light can usually be seen by using a cell phone camera. It will show up as a flickering bright spot on the image.
Please note the optic is in two pieces, one is on the door and the other is on the chassis. One is the emitter and the other is the receiver so you will only see the light coming from the emitter.

Ken · « **Reply #9 on:** November 16, 2020, 09:09:48 AM »

The 21 error is for the coin in optics below the comparitor and the info above is for the door optics. Opening and closing the door should clear the error as long as the door and coin optics are good. I believe that the 21 code will breifly clear with good door optics and a bad coin in optics. I don't know of or heard of any tips for checking the coin in optics with any type of light source.

Can you verify if the code clears for any amount of time?

Isn't there a way to go through the menus and check?

Stayouttadabunker · « **Reply #10 on:** November 16, 2020, 10:16:54 AM »

On top of the "Play 3 Credits" button on the reel glass display, watch the "Coins Played" display closely as you close the door.

The display should go out momentarily, then come back on.

If it does, then your door optic sensors are okay.

Now your [21] error...what is happening is that the MPU is sensing a fault with the coin comparitor, coin in optics circuit board, and/or it's wiring harnesses.

Make sure every single wire (Mostly orange) are fully inserted into their respective housing connectors that are around the coin comparitor.

It's very possible that one of them has internally broken and they is hanging by only the vinyl wire covering.

You are this close to the point of you having to UN-install that coin comparitor harness and manually checking each wired pin for continuity.

Chances are that one of the ground wires are not in continuity and causing the [21] error.

Most people are too lazy to do all the proper checking of wiring with a multimeter so my suggestion is simply this.

For suspect oxidization of Molex housing pins (male or female), with the power turned off, pull apart each white Molex connector around the coin comparitor and insert back in fully.

The very act of pulling apart the housings and re-connecting them scrapes the oxidization ever so slightly off of the pins and helps promote better electrical contact.

If all of the above doesn't work, then come back and we'll have more suggestions for you to get your machine up and running!

Good luck!

By the way...you posted this same machine problem more than once.

CaliforniaDreamer · « **Reply #11 on:** November 16, 2020, 11:32:20 AM »

Thank you, I will check the wires again. Looked at the before but now I will meter them. Also sorry for double post. I couldn't tell if the first post actually made it. New to the forum and figuring out the navigation.

CaliforniaDreamer · « **Reply #12 on:** November 16, 2020, 11:36:14 AM »

The 21 clears when I open/close the door but then comes back on in about 5 seconds. Also the winner paid lights for less than a second with a 12.

CaliforniaDreamer · « **Reply #13 on:** November 16, 2020, 11:38:00 AM »

Again thanks for all the help. I will do more checking after work today as indicated above.

jay · « **Reply #14 on:** November 16, 2020, 11:45:54 AM »

12 is a low battery.

Stayouttadabunker · « **Reply #15 on:** November 16, 2020, 03:09:11 PM »

Just a tip: Whenever you disconnect anything in a slot machine, turn off the power.
Not everything is plug-n-play....especially the MPU.

The battery on your MPU...is it the type with two flat tabs going to the positive and negative contact points?
If so, you can use a flat coin cell battery holder instead...the battery can be a fairly common 3 volt coin cell if you wish.
It will last quite a while but you need to be able to use a soldering gun to remove the old battery and solder in the new holder.
Let us know what you're capable of doing and we'll try to help ya.

CaliforniaDreamer · « **Reply #16 on:** November 16, 2020, 07:54:55 PM »

Thank you for all of the help. I have to apologize for posting things from memory, I posted some thigs that are just wrong. In any case thanks for pointing out where the reset switch is. On my unit it is on the back of the box with the power switch. Can't see it and I would have never found it. When I turn the machine on or open/close the door the following sequence takes place. After three or four seconds the "COINS PLAYED" displays 3, and the "CREDITS" displays 21. This blinks off after about 1/2 second then the "WINNER PAID" displays 21 and there it sits. BTW the "CREDITS" displayed 12 before, but I tried adding coins when the unit was locked with the 21 and don't know if that affected that display. Also I don't if it is important but coins added during the 21 lockup drop into the coin hopper not the bottom tray. Oh one other thing I haven't had time to meter the wiring yet but will. I did unplug both ends of the plugs and reseated them to no change.

CaliforniaDreamer · « **Reply #17 on:** November 17, 2020, 11:24:43 AM »

Just to verify, I have removed the CMOS chip from the board for 30 seconds and reinstalled the chip and the board. I then got a 61 error and pressed and held the self test switch. I then got a single ding and the display changed to 61 1. I used the side key switch to reset the error and it cleared but returned to the 21 error as described above. At this point I don't know what to do except replace the coin comparator. Any other ideas?

BTW I do have extensive experience with soldering and have a very good temp controlled soldering station. I also have a very good meter and did meter the cable from the comparator plug to the plugs on the bottom of the cabinet where the board plugs in, all good.

Stayouttadabunker · « **Reply #18 on:** November 17, 2020, 11:29:43 AM »

You might get lucky removing the Q2 chip on the coin in optics board below the coin comparitor.

There are many posts on NLG about this.

Try a search for it.

CaliforniaDreamer · « **Reply #19 on:** November 17, 2020, 11:35:28 AM »

Tried a search for Q2, Q2 coin chip, repair coin optics board, and Q2 chip with no luck.

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Author Topic: IGT Slot Machine Error 21 (Read 4797 times)