Coin-in Jam Error

[Lup]

Hey everybody. I'm testing a 044 MPU for a coin in jam issue.  None of the fixes posted on the site have solved this issue.  I believe I have a bad buffer chip on the MPU and need to check with my scope.  Only issue it the (memory?) board that plugs into the 044 MPU is in the way. Can start up the MPU without this board removed so I can test?  I'm assuming it's possible but wanted to check.  Thanks everyone, Kyle

[Lup]

Well I reinstalled everything and just going to test my Senet signals at the Motherboard at connector J7,8,9. I didn't have the correct scope set up but I will test and update soon.

[lookes]

Swap J8 and J9. See if you get a different error. All three of the SENET connectors are the same. (J7,8, and 9) Even if labeled DOOR, CABINET, etc.

I'd suspect a door I/O card, or the backplane. I've never seen a SENET buffer go bad on an 044, or 1270 MPU board. (Nearly identical SENET circuitry)
If you are sure it is the buffer chip (U36  LM339 Quad Voltage Comparator TSSOP14) Just replace it. Also check CR16.

If you don't have coin gear on the machine, make sure the plug with two loops is connected to the coin validator harness.

[Lup]

Thank you for the info. I will swap connectors. I have swapped both door IO cards, started with only one and swapped around. Even started with no j7,8,9 in and still have coin in jam. Although I do get bill validator error with coin in jam when everything unplugged. I will check these and report back. All the coin in jam errors posts I’ve read on here, are bad IO cards or poor connections. Pins all look great and given Deoxit with no changes

[Lup]

I swapped J8/9 with no changes. I swapped J7/8/9 to different locations with no difference.

The following signals noted with a scope
J7/8/9 pin4= 384 kHz 13v
Pin5= 13v with activity
Pin6= 13v with activity
Pin9= 13v with activity
Pin10= always high (13v)
Pin11= 13v with activity
Pin12= low (zero volts)

Pin 10 is concerning. Labeled TxB on the motherboard and Sen1 Ch2 D0 on MPU
Pin 12 labeled RSTJ on motherboard and RST on MPU.  Would assume a "reset" line and being low, is concerning.

I tested Sen1 Ch2 D0 (TxB) on MPU U34 (74lcx125) pin 4 (with soldered on jumper wire) and got LOW all the time. This line output from U48 pin 125 to U34 pin 4.

I need to trace down the RST line still.

Coin in Jam still showing.

Random 3 thoughts about this machine.
1. The Monitor was replaced on this before I received it. It appears to work fine but I noticed it has less pins in the connector has in the cabinet.  I remember seeing a post about the wrong monitor possible causing issues.
2. This machine had a dead battery when I received it. I put a new battery in and got the Error for needing flashed.  The next time I turned on the machine, it booted to the game and just shows the coin in jam error. I would assume since it booted the machine doesn't need cleared and flash.
3. The I/O test menu shows none of the front buttons being pressed. The buttons all light but not recognized in the test. The forward most door IO card slot shows LED 1 and 3 lit. The back IO card shows LED3 lit.

Sorry so long. Thanks everyone for your time.
Kyle 

[lookes]

Only two SENET transmit channels are used out of three.
Only one SENET receive channel is used. (Your problem is with this receive channel. That is why you get a coin IN error and the buttons don't work, but lights do.)
The RSTJ signal means it is the opposite of RST and is active low. It should hold low for about 250ms after power on and then go high.  SEN_RST follows this signal.

If you are ABSOLUTELY sure you replaced the door I/O cards with the correct ones, then try replacing the cabinet I/O card as well. (Has a short connector) It does use the receive channel for hopper coin out counting and to see if the hardware meters are connected on an 044. (The meters are probably jumpered)

It would be far easier to troubleshoot if you just substituted a known working MPU, or tried this MPU in another working cabinet.  Narrow it down. Don't forget there is a backplane involved as well.

The monitor has nothing to do with SENET, but the touch screen controller uses NETPLEX.

[Lup]

By swapping the door IO cards, I mean between the 2 that are in the door.   I have only this one machine. Swapping the card locations and by only using one, I get no change. 
To clarify, I'm not swapping with know good IO cards.  The two that are in the machine are all I have. I would assume the possibility exists that I have two bad IO cards. I have dissembled and see no visual obvious issues 

[lookes]

This is a classic door I/O card problem. Note that the two cards may, or may not be the same. (801 vs 802 card.) You can only swap them if they are identical. It just depends on if the cards themselves have different addresses, or if the card addressing is done in the card sockets. (In that case they will both be 802's) Just depends on the cabinet. I assume this is a 19" cabinet?

You need to get some known good Door I/O cards to try. You will never figure this out looking at SENET signals. All three cards share the SENET receive line. They just don't cost that much.

Again, out of around 100+ 044 MPU's I have repaired, NONE of them had a problem with the SENET system.  Same with 1270's. I've never had a SENET problem with one. (400+). They have a much better electrical design than 039, or 50X boards, which often have SENET faults. Maybe I've just been lucky lol...

Send me your MPU. I can test it and rule it in, or out.

[Lup]

Thanks for the reply. I did find a local supplier and will see about known working cards. Both of mine are 802 cards.
For anyone following along, I do have input to the MPU at U48 pin 126. Baseline of approx 3 volts with random activity down to ground. This is the one SENET line as mentioned before.

I will get working I/O cards and report back.

[Lup]

And it's fixed.

Two known good working Door IO cards fixed this Coin In Jam error. 
I know this has been discussed several times, but I thought there was a slim chance that both were bad. I was incorrect in my assumption. The fact I had no front button response in the IO test screen was probably the biggest clue.  This is my only GK so I do not have other IO cards laying around.

Thanks to Lookes for the help!

[Stayouttadabunker]

A long time ago, I found a couple of bad door I/O cards (vertical and diagonal circuit boards) on an S2000.
I don't remember which numbered versions they were (802's?), but recall they were under a two-row, 10-button deck.
Taking off the metal enclosures (The half cover with plastic and handle) for the door I/O circuit boards, revealed a blown-up C5 cap chip.
I suspect that someone had either removed, or inserted the I/O cards with the machines' power switch ON?

Click on any photo below to enlarge if needed...>>>

[Lup]

Thanks for the reply.  I've seen pictures of those caps blowing up and I also would assume that's from a hot swap with power on.
The caps in mine all test to their rated values in circuit. I see no visual issues with anything, so my best guess is with one of the IC chips that controls all the outputs.  But for now, I'm up and running