IGT S+ error 21. Tried everything

[Thorn1724]

Hello I'm new to the forum and need some help.  I have researched everything I could before asking for help.  Definately need some expert advice at this point.

History:  I have an 86 IGT S+ quarter slot that worked fine and started to get the error 21 coin tilt. I have done the routine checks.
1. Clean optics,  checked for obstructions no issues
2. Verified correct quarter spacer
3. Wiggled and removed harness and re attached
4.  Self test Coin comparator  in mode 34,  drops in coin return and pull handle green light comes on and coin falls in hopper. Seems to work perfect in test
5. Verified door optics. 13-1, 13-0 flicker as should when door closed
6. Open door and close… 21 disappears,  reel cycles one click and 21 code re appears
7. Test optics 10-1,11-1, 12-1.   This is the first issue I see the following
 10-1 correct  ( remove the 10 pin connector on optic board, and 10-1 switches to 10-0,  no  changes on others)
11-0 not showing  the 11-1
12-0 not showing the 12-1
Test small white credit button and no luck
Remove comparator and cycle coin, cardboard, popsicle stick in front of all optics and no changes on any of the optics
Look at led under camera no lighting

8. Bought new supposedly functioning optic board and did all the same test. Exact same results
9. I put the  Multimeter on the 10 pin connection and appears to have voltage on all 6 of the 8 legs . Could this be the issue.  I can send results on each colored wire.

I guess big question is im not seeing any changes even though I changed the optic board. Still seeing 10-1, 11-0, 12-0 and white button doesn't do anything.

Hopefullly I provided enough detail to start.  I'm thinking bad Harness or board at this point. Thanks for your
Time and advice.

[Jim]

probably bad connections at the optic board . easy way to check, pull the connector and hold it up to a light source, now look at each pin inside the plug opening, you should see some opening at the very top, if you see a big gap on any of the pins ,remove those pins and reshape and re insert. Did you check the connection at the machine plug , this is where the cc-16 harness connects into the machine harness that eventually ends at the top of the board cage.

Jim

 

[Thorn1724]

Thanks,  I’ll check the connector and take out all the wires and space appropriately. It is possible I pushed them in further with multimeter  .  I didn’t use the open tabs on the back of connector during testing. As for the harness connecting to the cc-16 to main harness , I removed and inspected as well as checked the voltage on all the legs but I’m not sure which one should have voltage or not other than the red and green wire. I think two of them had around 8v and 4 of them had around 4-5 volts.  The green ground o volts and one other leg had 0 volts.   Will check again and provide voltage with color coded wires.

[banyans]

Hey, Im not the expert but noobie me had the same error 21 issue. I tried several different things as you did, what worked for me was pulling the big main board, turning on the machine for a second and then reseating the board. Its not the technical way the experts know but it worked for me.

[Thorn1724]

Thanks I'll will probably try that.  Below is some more data on the voltage if anyone can help if I have a connection issue.  Does any of this make sense.  Especially the orange/ yellow and orange/blue
I got the same voltage results on two different optics

At cc/16 harness.     At 10 point.    10 point connected to optic
Orang/blk 4.88v.         4.88v.                4.88v
Orange/Brn 7.4v.        7.4 v.                 7.4 v
Orange/yell 4.9v.         4.9v.                  4.9v
Orange/red. 4.8v.        4.8v.                  1.46v???
Orange/green 0v.          O v.                  O v
Empty slot
Green.            0v.          0 v.                  0v
Red/blk.        8.2 v.        8.2 v.               8.2 v
Orange/ blue 0 v.            -3.1 v.            -3.1v
Empty slot

[Trisail]

My S+ cc/16 D 100 Rev F has -
( The measurements are starting from the bottom of the optics connector up to the top, hope it is not confusing. The wire colors are what matters. )

               Pin     10 point connected to optic
Orange/blk        1          .8v    'C' out
Orange/Brn        2         4.73v   +VB
Orange/yell       3          .8v    'B' Out and tiny white test switch bypasses this optic (circuit)
Orange/red        4         1.9v    'A' Out and Credit signal out
Orange/green      5         0.v     Gnd
Empty slot        6
Green             7         0.v     Gnd
Red/blk           8         9.4v    LED +V
Orange/ blue      9         0.v     Pulse/Enable
   
I will check the prints for any info I can pass on to you.

Tony

[Thorn1724]

Interesting… thanks for supplying the voltages.  Same sequence of wiring, definately different voltage reading between the two. Got me thinking just don’t know what it means yet.  I’m running a cc-16D ,4B comparator. Thanks

[Trisail]

I made a few edits to clear up the table and added the signal names in the previous post.

So going by just how the devices work, the schematic and my knowledge of what I think the voltages should look like For My Optics readings at power up and init -

Pin 1 -  is telling me 'C' out optic is working - meaning the LED is on and it turned on the output transistor which switched in a ground. (OK)
Pin 2 -  +VB is getting to the board, and looks like it is going to the devices on the board. (OK)
Pin 3 -  is telling me 'B' out optic is working - meaning the LED is on and it turned on the output transistor which switched in a ground. (OK)
Pin 4 -  is telling me 'A' out optic is working (but I think it should be at .8v like the others, maybe it has a problem but it's working) - meaning the LED is on and it turned on the output transistor which switched in a ground. (OK)
Pin 5 -  ground (OK)
Pin 6 -  NC (OK)
Pin 7 -  ground (OK)
Pin 8 -  LED +V voltage is telling me the 3 LED's are working (+VB - 3 LED drops voltage looks OK.  ~ 13V - 1.2 -1.2 -1.2 = 9.4V) (OK)
Pin 9 -  is a 12ms pulse - the voltage will be low on a meter all the time. (OK)

Now for your readings at the optics board -

Pin 1 -  is telling me 'C' out optic is not working - meaning the LED is not on and the output transistor is off. This would tell the machine optic 'C' is blocked all the time.
Pin 2 -  +VB is getting to the board, and looks like it is going to the devices on the board, but all the devices may not be working, the board is not pulling enough current to lower the voltage like mine is. This may not say there is a bad device on the board, it may just mean your LED's and other problems may be the problem. I believe both the optics boards you have are OK.
Pin 3 -  is telling me 'B' out optic is not working - meaning the LED is not on and the output transistor is off. This would tell the machine optic 'B' is blocked all the time.
Pin 4 -  your voltages -  Orange/red. 4.8v.        4.8v.                  1.46v???    this is telling me 'A' out optic is not working, the voltage to the optic board is not getting to the optic connector, the 4.8 at both the 1st connectors looks OK, but your reading of 1.46v is telling me there is a problem with the wiring (probably not the transistor on the optics board) The 4.8v is telling the machine the optic 'A' is blocked all the time. The credit signal also goes out this pin to tell the machine to add a credit and enable a game to played.
Pin 5 -  ground (OK)
pin 6 -  NC (OK)
Pin 7 -  ground (OK)
Pin 8 -  LED +V voltage is telling me the 3 LED's are working (+VB - 3 LED drops voltage looks OK.  ~ 12V - 1.2 -1.2 -1.2 = 8.4V) (OK) ( You may be using a 12 V power supply?)
Pin 9 -  your voltages -   0 v.            -3.1 v.            -3.1v   this is telling me the wire is probably good from the 1st connector back to the motherboard. The wire is broken from the 1st connector to the 2nd connector hence the 3rd connector. That negative voltage is telling me you have an open circuit (bad wire) or you are not on the ground - the voltage is floating. The Pulse/Enable signal will never get to the optics board. The optics will never send a credit signal to the machine.

With all that said, here is my take on what is wrong -

It looks like the LED's are on, there is a voltage drop on the LED +V. It looks ok to me that the LED's are actually on, I could be wrong. With pins 1, 3 and 4 not reading low, the transistors are not turned on. I believe your optics boards are both OK. I would recommend - repair the wires I think are bad. From your 1st post and the results you mention on testing and using another optics board, you have wiring problems. You could probably buy the cc harness you mention ( I posted a picture of mine below ) and fix your 21 problem. My harness has a 12 pin Molex that connects to the mating connector in the door just to left of the CC. Then the 10 pin 'brown' connector connects to the optics board header. ( The other wire harness is for the diverter and another for the CC ) I am not exactly sure what your labels - At cc/16 harness.     At 10 point.    10 point connected to optic  - are saying but I understood that to mean you checked at 3 connectors ( my reference above is for that about the 1st, 2nd and 3rd connectors )

My suggestion is purchase a harness and I think your machine will be OK.

Hope this helps,

Tony

So here is some CC/optics info if anyone is interested.
The credit output signal that goes out Pin 4 ('A' optic circuit) is timed with the coin comparator and the optics circuits to tell the machine a proper coin was inserted and passed through the optics as valid, put a credit on the machine and enable game play.
The tiny white test button on the optics board bypasses the 'B' optic circuit allowing a credit pulse to go to the machine for testing. ( It in effect bypasses the CC signal and optics timing circuits with the door open )

[Thorn1724]

That is some great information and detailed explanation.  You knocked it out of the park.  I have a better understanding now of how the circuits are to work.  I will take your suggestion and get a new harness.  The harness you posted is exactly the same as the one in my unit.  Will give an update once I replace and test
Thanks again.

[Thorn1724]

Update: I received the harness today as worked as advertised.  No more error 21 and everything is functioning.  Bad wiring harness was the culprit.
Thanks Tony

[Jim]

Glad you fixed your problem, 98% of the time it is the harness,  if you send it to me they can be repaired.

Jim