S+ reels 'jumpy' on startup

[Bob L]

Hi, I've had an s+ double wild cherry slot for a long time and a month ago it wouldn't power up correctly.   I fixed the power connector with trifurcon connectors, and now when I start the machine, the lights come on, the bill acceptor self checks, and then all three reels do a 'jumpy' spin (moving mostly forward, but jumping backward randomly).   The reels continue this jumpy spin as long as it's powered on.  I'm wondering if it has something to do with the stepper drivers.   I've resoldered some of the power connections to make sure they're ok, and I checked the resistances on the reel resistors and they look ok (465-481 ohms).  I did notice some 'browning' on the board near the three active reel resistors, and near one of the larger diodes (which I also resoldered just to be safe)  I don't have a field service manual, and would like to get one but I haven't seen anything for my 'REV C' board.  I've checked the fuses and they seem to be ok, and I'd like to check the voltages for the power, but I'm not totally sure how (I've read different things).  I have a scope and other diagnostic equipment, but I'm unsure how to proceed.   Any ideas would be greatly appreciated.

[Stayouttadabunker]

Be honest with yourself, did you at any point, take out or push in the MPU, while the power was on?
Power surges cause flaky machine behavior, because IC components on the MPU can get zapped.
Winter static electricity arcing across fingertps to IC components do damage as well.

I've seen "jumpy" reels, but not so bad where they've spun backwards.
Only certain SP chips running with "Deluxe" Type games can make a reel spin backwards.
Think of the SP chip as your "Windows 10" operating system, but to make a reel turn backwards , it needs to run with certain SS game chips.
I can only think of the Haywire games doing exhibiting that behavior - during a bonus.
Double Wild Cherry doesn't do this.

Follow this drawing below I made years ago to check the voltages going into the motherboard power Molex.
Check by sticking your red multimeter probe (Set to vdc) into the top of the white Molex power housing, of course, with the machine's power switch ON.
Your black multimeter probe just touching cabinet metal ground.

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

[Bob L]

I've never unplugged the motherboard powered on.  If you think the motherboard is the culprit, I could try to buy a matching one to replace.   There's always a chance I inadvertently touched something, but I'm generally fairly careful.   I did check all pins on the motherboard connectors and none were bent.

 I checked the voltages - I don't get readings DC, but for AC pins come in at 0V, 0V, 7.8V, 8.9V, 12.6V, 12.6V.   It's interesting that the two middle legs are a bit different.

The reels generally move forward, but occasionally will stutter backward for a step.  It's not the fast spin I used to get on start up, it's a slow forward stepping with an occasional backward step.

I tried to post a video showing the behavior, but it didn't like a .mov file....

[shortrackskater]

To post videos, just put them on Youtube and post the link. 
Stayouttadabunker is talking about the MPU (or CPU) board, and not the motherboard. 

[Jim]

no. its correct, one voltage is 7vac, the other is 8vac, so they are good.  sounds like you have ripple on the dc voltages on the cpu board.  tough to get to see those voltages, only way would be to extent the test points via a wire.  when the reels are locked in position, is it real easy to move them using one finger, if so then I an pretty sure you have some bad filter caps on the board, usually the large black caps.

Hope this helps

Jim 

[Bob L]

Sorry, I meant to say I have never unplugged the MPU/CPU when powered on - I've never unplugged anything in the machine while it was powered up.  Also, I meant to say that none of the pins on the CPU/MPU were bent. 

I tried uploading the video of the reels to youtube, here's a link (first time doing this, so let me know if it doesn't work).



  Thanks,
    Bob

[Bob L]

Jim, when I power the machine on, the reels 'snap to attention' pretty quickly and become firm.   None of the reels is easy to move (like they are when powered off).  I do have a storage oscilloscope up here, so I could look for ripple if I know the points to probe.   

FYI, I'm including a pic of the MPU board I have....

Sorry the pic is lower resolution, but when I look at the higher resolution picture, one of the 1N 5401 diodes looks a little different, and I think it's the same one that the solder looked a bit different on (I resoldered all of them).   I'm wondering if that diode has a problem.  I don't have a schematic of the CPU board so I'm not sure what it's for....


  Bob

[Stayouttadabunker]

Oh wow!
Great video Bob!
I have NEVER seen reels start up like that.
They are all screwed up.
Are you sure there's no bent pins touching each other?
I'm going to bet the reel prom got corrupted or something zapped the reel drivers on the MPU.
Is the reel prom in the socket in the right direction?

The reel drivers are the four chips with heat sinks that look like butterflies (Just right of the transformer)
You'll see the empty socket for a fifth driver.
They were for some rare five reel S+ machines a long time ago.

[Bob L]

I looked at the pins (both sets on the edge of the MPU board)  with a magnifying glass and they all looked very straight to me.  I haven't removed any chips since it was working perfectly (for years), so the chips should all be plugged in correctly.

I do see one interesting thing when I zoom in on the MPU photo - it looks like there could be some slight discoloration of the board near the butterflies of one of the chips.   It also looks like one of the 'butterflies' is near (but not touching) another solder point on the board.

I will post a zoomed photo in a bit (Waiting for photo software to update....)

[twinfire]

Wow, looking at your video that thing is possessed!

After Jim’s comment about the Caps I looked at your board picture. Although the pics aren’t all that clear, two of the Caps kind of look questionable? Are the tops of the ones indicated by the yellow arrows raised at all? They should be completely flat on top.

[Bob L]

I'm attaching a zoomed in pic of the reel chips with the discoloration. 

Is there a schematic for the REV C board version?  I'd like to see if the interesting diode has some connection as well before I order a replacement.   

Is it possible to get replacement reel chips alone, and is there any info on how to test the reel chips?  If I had some schematics, I might be able to probe at the reel plug to see how things look.   I could debug some of this stuff if I could get some documentation, but I haven't been 'reel' successful at finding any.

  Bob

[Bob L]

Hey Twinfire, the caps seem pretty flat on top when I place a straight edge across them.  Is the CR2 diode in the reel circuit?  I think that one might be questionable.

[Tilt]

You're a contributing member, you can find some schematics here:

https://newlifegames.com/nlg/index.php?action=downloads;cat=93

[Bob L]

Thanks for the link Tilt!  I'll try to dig into those tomorrow.

  Bob

[Stayouttadabunker]

U10 is the butterfly reel driver for the 1st left-most reel.
It looks like it's been overheated.
It looks black under the heat sinks.

What's your zip code?
Maybe I could run your MPU & reel chip on my test machine if you're not too far away?

[Bob L]

Hey Bunker,
  I’m near Sonora, California.

[shortrackskater]

What's your zip code?
Maybe I could run your MPU & reel chip on my test machine if you're not too far away?

I think he's a little far from you Mark. 

[Bob L]

I've been doing some homework on the power supply and reel circuits.   It's challenging because I can't access the board while its powered up.   

I did probe L1 and L2 of the middle reel with the scope (at the reel connector), and the square waves aren't great, but I think that might be expected because it looks like the 1042 chips are being driven in half step mode, and the outputs become high impedance at times in that mode.  I've attached a picture that shows the waveforms, and it looks like they're running at 10.8 and 11.0V peak to peak, which looks like it's within the required range for the motors to be driven (i.e. the 11.5V +- 1.5V ).   I didn't check out L3 and L4, but I will check them later. 

I'm wondering if the problem is somewhere else, i.e. maybe with Vb, but I haven't been able to probe it (I did see that the solder points at CR2 looked a bit sketchy, but it looks like the diode tests ok).  I also noticed that R97 looks a bit 'crispy', but surprisingly the resistance tests ok.    I may try to solder on some test points (I can't find any test clips that are small enough).   Does anyone have any recommendations on better way to access the voltages short of having a test machine (I don't think Mark will meet me in the middle to use his test machine :-)

Has anyone ever tried partially powering the CPU board to very the function of portions of the power supply at a time?  I'm not at the location of the machine for a bit, but I do have the mpu board with me.   I'm looking for cheap ways to be able to diagnose things outside of the machine...

One last question - I'm a bit perplexed at how the power supply gives the 11.5V at Vs given the higher incoming voltage (24V AC).     Is the 5810 doing some kind of 'poor man's PWM' to keep the voltage lower?

[Badbaud]

The TIP125 power transistor starts the reel power with close to 24 volts.
After the reels start spinning at 24 volts there is a 2N3904 transistor that powers the base of the TIP125 and drops the reel motor voltage (via theTIP125) to around 15 Volts to maintain the spinning.
The 24 Volts give the reel motors a boost to get them going, then that voltage is dropped down and maintains the spinning.

[Stayouttadabunker]

...Is there a schematic for the REV C board version?
Is it possible to get replacement reel chips alone...

Bob,
Have you looked in the NLG File System?
There are MPU board schematic diagrams in there in the IGT Games, subcategory area.

I've tried changing the butterfly reel drivers...I've had some luck, some didn't work.
A lot of these IC components are obselete now but different places sell chips...you just have to search around.
Personally, I get a lot of stuff straight from China, but I search first at places like Mouser.com, Digi-Key, FutureLec, oh there's so many places.
China takes long so I look in the States first.
Often I just order parts, forget about it, and when it comes in, it comes in.
You would get China parts faster than me because you're on the west coast.