1994 S+ 5x Pay that sometimes works perfectly - then it breaks w/ no errors

[Daveg225]

Normal operation - all functions working.
If I leave it powered up it can just stop working.  All lights are normal EXCEPT:
- Insert Coin, Coins played, bill receptor "$1, $5, $10, $20
- can also stop working when in play
- all coins just drop thru

The Florescent lamps are on and the 5-cent lamp to the left of the coin slot is on.

I can sometimes get it to work again by powering off, re-seating the MPU board and/or pushing on all the molex connectors.

Reels are powered up - can feel slight tension on them.

I just powered off, reseatted MPU, pushed on motherboard connectors and power on.
Normal cycle up of money receptor, but bottom coin drop counter is incrementing 1-click per 1/2 second and all 3-reels are moving slowly.  error code 42 in winner paid which indicates Reel tilt 2.

Pressing white reset by power toggle switch is no help.

[rokgpsman]

This could be the classic failure of the power supply connector that connects to the motherboard. Inspect the white molex (plastic) connector, look for any darkened or brown places, be sure to check the backside of the white connector also. The darkened area indicates overheated electrical contacts due to poor mechanical contact. The mating contacts need to be cleaned or replaced. Many times you can clean them with something like light sandpaper or a pencil eraser. Be sure to clean the male pins on the motherboard that mate with this connector.

Pushing or wiggling a white molex connector and things start working is a sure sign of an intermittent connection in that connector and it needs to be repaired, otherwise it will fail again and again.

[knagl]

I agree, sounds like the power connector. With the machine off, remove, clean if possible, and reseat that connector.

To clear your reel tilt (42) error, open the door, turn and release the jackpot reset key on the side of the machine, then close and latch the door.

[Daveg225]

Thank-You for the reply - I appreciate any and all info I can get.
I did check that molex connector ( assume J8 on Mother Board ) - no burnt color.

I cannot tell from your picture, but is there a cable plugged into J9 ?
I may have pulled this one out earlier in cleaning and forgot to put back.  I found it later not plugged in and plugged it in.  Someone told me it may have been unplugged for a reason - so I am 2nd guessing myself.
Should J9 be plugged in?

I assume I can safely power off / on - keeping the door open to visually see if the machine looks normal.

Do you think the Processor board is ok since when it works it plays normal for 30-minutes or more?

In the failing condition I am looking for some way to isolate the failure, like measuring voltage, etc.
Or would it be best to measure resistance with the power off to confirm connections are good?

Thanks!

[rokgpsman]

Another thing to check is the fusecaps, they can get to fitting loose due to their worn metal parts or a weak spring inside on the bottom side of the fuse. When the machine malfunctions try tapping or pressing down on the fusecaps to see what happens. Or with the machine unplugged check each fusecap for tightness, it should press firmly against the fuse inside when the cap is installed and twisted into place.

Have you inspected your mpu board (the main logic board)  to look for any water damage or battery leakage? The processor board (mpu) is probably ok since it plays ok for that long but I'd still look it over anyway.

It is ok to turn the machine on or off with the door open but the machine won't play as normal, for example you won't be able to insert a coin or bill and get a credit. You can use the pseudo coin pushbutton near the coin optics to simulate a coin acceptance and get a credit and spin the reels. This verifies most of the machine is working or not.

Your symptoms still make me think you have a power problem, so if it isn't a bad motherboard power cable connector or fusecaps then I'd check for other bad connections or maybe swap out the power supply assembly.

Is this a new machine to you or has it worked for quite a while until this happened?

[therockinelvis]

Here is a diagram of what you need plugged in to mother board.  I too think it is the power supply cable even though yours is not burnt. Pull the molex about half way up the pins and see if you get a good connection.

[knagl]

I did check that molex connector ( assume J8 on Mother Board ) - no burnt color.

Even without the trademark burn color, it may still be making a poor connection.  Did you disconnect and reconnect it, and is there any difference?

Also, when the machine is not working properly, are the reels still stiff then?  I saw your earlier post saying that the reels were stiff, but I wasn't 100% clear if you meant that they are when the machine is malfunctioning.

[Daveg225]

  !!!!!

I looked very closely at the power supply cable going to the MB at J8.  I saw a very faint burn mark on the molex white connector on the 2nd green wire from the end ( same as pix above ).

I tried cleaning it with contact cleaner and then alcohol but still no help.  Then I pulled up on J8 a bit to get some new contact area -  and we have a winner !  I played it for 40-minutes with no problems just using the Play 3-credits button and feeding it dollar bills.  Then I got brave and used the pull handle.  After the 3rd pull it went dead again - no LED for Winner Paid or Credits, or insert coin / coin played.  I am thinking the extra vibration of the handle makes the P8 connection go out again.

To fix, opened door and powered off.  Pulled out the hopper.  Pulled up and down on P8 at the MB.  Put the hopper back in and powered on.  I know when I see the candle blinking it will work - so closed the door.

Back in business so I think you are correct - P8 is bad.  I will remove the green wire and replace the pin.

I am so grateful for your help with this !!

Dave

[Daveg225]

I attempted to fix the crimp connector and it did work for another 30-minutes of play.  But leaving the machine idle for 15-minutes apparently lost the connection and it went dead again.  So I will replace the crimp connector or maybe just solder that 2nd green wire on permanently.

I attached the type of crimp connector P8 is made up of - it really is not a molex connector.

Loving my slot machine - when it works !!

Dave

[therockinelvis]

The original only makes contact on 1 side of the post. New replacements touch 3 sides/

[rokgpsman]

They make an improved version of those contacts, it is similar to the photo below. Places that sell molex and other electrical connector parts will have them. I don't know the Molex part number, maybe someone here that has replaced them can provide that info. I think they are sometimes called "trifurcated" contacts because the new-style one makes contact on 3 sides instead of just one. But even if you just replace the contact with the original style it will fix things for quite a while. Be sure to shine the mating male pins on the motherboard. Liquid stuff like contact cleaner won't fix it. You either have to replace the contact or scrape/rub it with something abrasive like sandpaper, pencil eraser, etc. You don't have to clean the entire contact, only the mating surfaces have to be shiny.

As these contacts tarnish over the years a resistive coating forms on the surface. When electricity flows thru a tarnished connector it get warmer and then more tarnish forms, so it gets even warmer, until eventually the electricity doesn't flow. You can temporarily improve the connection by sliding the connector around but the problem will return. On some of the connectors the signal or electricity is a small amount so it doesn't cause very much heat-induced tarnish to form, may never fail. But this connector is from the power supply and a few amps goes thru some of the contacts. That's enough electricity to get the heat-tarnish-heat cycle going and that's where the problem occurs.

[Daveg225]

I have a manual for the S+ but it does not match my machines wiring.
Is there a simply power supply wiring diagram showing mother board P8 to the power supply?

Otherwise I will just duplicate the existing cable with new connectors.

Thanks

[rokgpsman]

I have this, it might be what you need:

[Daveg225]

I have this, it might be what you need:

PERFECT !!  Now I feel better about taking the wires out of the plug and attaching new crimp ends.

Thanks.

[rokgpsman]

Another idea that can be useful, nowadays a lot of people take a few photos with a digital camera or camera phone before and during disassembly. Easy to do and comes in very handy when you go to put something back together, especially a few days later.

[Daveg225]

    My journey continues !!!   ( sorry if too long winded )

Replaced all P8 crimped connectors with new ones - left the Power Supply end original as those pins make a much better connection.  Metered the voltage at P8 and confirmed 7vac, 8vac, and 24vac all good.
BUT ... still having the problem where it quits working as detailed in my first post.

I did my normal pushing on boards, connectors and powered up - things back to normal.  I tip-toed around things pressing very gently on a specific area of the machine.  When I got to the Processor Board (MPU) I BARELY touched the edge of the board close to the blue pot (volume control) and the candle yellow light went out.  ( Candle yellow light out with door open is my indication the machine stopped working ).

Upon further investigation - I pulled out the MPU and took another close look at everything.  Removed the board and looked for any indication that the CBoard was shorting out to the aluminum case.  And then I spotted it !!  Look closely at the attached pix showing the Reel Chip.  Around pin 9 - 11 there is a glob of solder shorting the pins together.  I assume this is NOT normal.

To back up a bit, I originally had an error code 12 - "low battery".  I took the MPU into a slot repair store and they soldered on a new battery.  I went thru the 61-1 steps and it worked for a short time.  Then started having this non-operational loop.  I am thinking it may be possible when the tech cleaned his iron he may have flicked it to remove excess and it landed on U53?

In any event - I am thinking this is my problem.  My Liberty Belle book is mostly showing 1986 schematics and does not match my S+ 1994 ; MPU has 4 large caps in a square pattern - not in an L-pattern as the book shows.

U53 is a 28-pin Reel pROM and I assume looking down from the top, left of the notch is Pin 1.  This would make the solder shorting out pins 10 and 11 and possibly touching pin 9 too.  Does anyone have a schematic showing U53 details ?

And the dilemma I have now is what is the best way to remove the solder w/o damaging components or the board? Initially I am thinking a braid de-solder or solder sucker tool?  Maybe just cut the solder between pins with a razor?  I am afraid to remove the Reel pROM while doing this that may reset things if out of the board too long?  I do not have a clear chip to reset with.

Thinking ... Standing by.

Thanks

[Shaggy]

Good find. I don't know if it would cause all those troubles or not but it can't be helping anything.  I've done lots of soldering and generally when a drop hits an unprepared spot it won't stick too well. Removing the reel chip shouldn't bother anything. When you change Reel chips you just have to clear the 61 error which you already know how to do. I wonder if just a gentle touch won't move it loose. If it was mine I'd reach down and try to pull it loose with my fingernail or maybe an ice pick. Just my thoughts.

Dave

[Daveg225]

Thanks for the reply Dave.
I was mostly concerned about removing the Reel chip as I did not want to have to do the set/clear chip routine.  but if you are saying I can leave out the Reel chip and only have to do the 61 reset I will pull out the chip before heating up anything.

I tried scraping but it is really stuck on the board. Even tried a small blade knife but would not lift it.
I may try a small tip soldering iron with a quick pass between the pins.  Maybe I will get luck and it will clear.

I am really curious what pin 9-10-11 are ; if anyone knows.

Thanks

[Shaggy]

Thanks for the reply Dave.
I was mostly concerned about removing the Reel chip as I did not want to have to do the set/clear chip routine.  but if you are saying I can leave out the Reel chip and only have to do the 61 reset I will pull out the chip before heating up anything.

I tried scraping but it is really stuck on the board. Even tried a small blade knife but would not lift it.
I may try a small tip soldering iron with a quick pass between the pins.  Maybe I will get luck and it will clear.

I am really curious what pin 9-10-11 are ; if anyone knows.

Thanks

Yeah I didn't want you to think you had to clear or set or anything like that. I changed Reel chips in my Haywire machine a couple of months ago and only had to clear the 61. Sounds like its really stuck. Sorry I don't have the stuff for 9,10 or 11. Good luck.

Dave

[Jim]

Hard to believe that changing the battery would cause a glob of solder to be so far away from the point of soldering?  and then to be stuck that you can't flick it off, as Dave said, errant solder typically doesn't stick too well and is usually easy to remove, I don't think you would have to remove the chip, your soldering tip won't be on that area long enough to heat up anything but the solder. 

Pins 10 and 11 are address lines  and pin 9  is a data line,  all three chips have those lines running in parallel with each other. 

in your first post you stated that the denom lamp was on and the reels were stiff,  that removes all doubt about the power connector, if the power connector were not making contact, neither would be working.

Jim