Troubleshooting Process...

[wutsit4]

Hello again,
With most of my other arcade machines, problems generally seem to focus around connectors.  In order to troubleshoot my IGT Esprit, it seems that I first need to verify the integrity of the wiring harness.  I can't get the credit display to properly illuminate.  This should offer some diagnostic codes if I can get it to work, but I can't tell if the display board is bad, the connectors are bad, or the computer boards are not feeling well.  I have seen the hopper spin up and spit out coins, if I remove the reel assembly and power up the machine.  If I install the reels, only one reel spins.  Without the display, I can't tell if the reel positions are being read.  Between the two reel assemblies, I hope to have enough good parts to make one working reel set.

I am replacing the connector that feeds the display board, as I can see it is needed.  Where do I begin?  I have 2 of these machines, and can swap parts back and forth, but I can't seem to focus on what to try to fix first.  Any suggestions would be appreciated.  Tried each board in each machine, but still no luck.  Reseated all socket mounted chips.

Just trying to salvage one machine from the two that are on the bench now.

Thanks in advance,
   Keith

[Op-Bell]

As I mentioned in the other thread, I would at this point replace the RAM with known good devices.

[wutsit4]

Thanks for the reply.  One of my boards has what I think are the ram chips soldered in.  The other board has them in sockets.  In trying to start from the beginning, I thought the electrical problems were over when I stopped blowing fuses.  I just metered some of the wiring harness, and it appears that I have a good 12V supply, but the -12 volts is closer to 18.  One power supply puts out a good 5 volts, while the other only outputs about 2.7 volts.  Neither is generating the - 5 volts.  I took the board off of the "better" power supply and checked out what I think are diode bridges, although they are mounted in a vertical rectangle with all four taps on one side.  It appears that two of them may need replacement.  After tomorrows trip to the electronic parts store, and a bit of soldering, I may have a further update.  Hard to tell if the computer boards are working, if I am not providing them with the proper power.  Figure I'll do the diode bridges first, and then see if I need to replace any of the externally mounted "transistors"?  If I must work on electronics, I do alot better on vaccum tube based stuff.  Welcome to the 25th century.
Thanks again,
   Keith

[wutsit4]

Latest Update.  Not yet electrocuted.  Replaced two Bridge Rectifiers, the 5 volt regulator (transistor?), the 12 volt regulator (transistor?), and a couple of the other chips that mount with a screw to the heat sink.  Put the power supply into the first machine without the reels and hopper, and something on the door started to smoke.  Shut down everything and tried the same power supply in the other machine, no reels and no hopper.  Checked for voltages at the small computer connector and now I had a (+) and (-) near 5 volts, and a reasonable try at 12 volts.  Connected the computer and display board and powered up again.  After a few seconds, the display lit up (minus a few segments) and everything looked reasonably stable.  (No Smoke).
I shut everything down and replaced the female DB25 connector that goes to the display board.  Now all of the displays could lite up properly.  I installed the reel set and put the service switch to position 2.  Clicking each reel into each position showed that the machine can read the reel positions on each reel.  Amazing.

I was able to poke around inside for nearly an hour.  Then it appears that a resistor (R2) blew up on the power supply board.  A chunk is missing, and the color bands may have burned a bit.  Does anyone know the value of this resistor?  The one on my other power supply looks different.  Guess I'm back to the electronics parts store when I get a chance.  Needless to say, the display went out.

When things looked OK, on power up, the reel motor would run and turn the cam shaft about 1/4 turn and then stop.  I checked the home switch and it appears to be working.  In prior efforts, I have seen the motor run endlessly.  Now it is stopping before hitting the home switch.  I have not seen any of the reel solenoids fire.

The hopper did not run at all on power up.  Should it?

A service manual would really be helpful.  Any suggestions would be greatly appreciated.  Bet some parts that have not seen power for years are not amused.  Are there any other diagnostics that I can access if I get the display to light up again?  The only thing I can recognize as a definite problem is the tilt light comes on.

Thanks for your help.
   Keith

[Op-Bell]

R2 burning out means you lost the 5V supply. That should not have happened. Check your email for a manual.

The reel motor should run to home and stop, so there's something wrong there. The reels should not fire, and the hopper should not run, so that's good.

[wutsit4]

Thanks for the coaching thus far.  Still think that I have a power supply problem.  I seem to be carrying AC on the DC power lines... Seems wrong to me, but I really don't know.  Metered the power supply ins and outs - not getting a good 12 volt DC unregulated output.  When I pull connector S1, the computer power cable, and read voltages there I get the following.

Should Be                           DC                       AC
+5                                     +5                       10.2
-5                                      -13.25                  0
+12                                   +12.1                   25.7
+12 unreg.                         flux-unstable          44.9
+5 unreg.                           +12.3                   26.2

I am hoping that this shows a pattern that someone familiar with power supplies may recognize.  It seems that I should be blocking the AC from the computer box, and that I should be generating the 12 volt unregulated.  I looked at the schematic, and traced the lines, but I don't see where the unregulated 12 volt comes from on the 24 volt AC lines.  They seem to go from the transformer directly to the outputs.  Any guidance would be appreciated.
   Keith

[Op-Bell]

What are you measuring these voltages with respect to? Any DC voltage measured with respect to the door or chassis metal will be wrong, as it will have part of the 24VAC added to it. On this machine, 0V is not the same as Ground.

[wutsit4]

I was measuring from the contacts in the connector S1.  Pin 1 is 0 volt.  I checked the other voltages in the connector with the negative reference to Pin 1. 
Thanks,
   Keith

[wutsit4]

Today, I replaced another bridge rectifier, B4.  Now I seem to have the voltages needed to run the machine, but I still read AC riding on the DC lines.  After shuffling the 6 6821 chips around, and getting various combinations of partially functioning parts of the machine, I managed to install the chips in a sequence that allowed the display to work, and on power up... the display lights up, the reel assembly goes to the home position, and the hopper just sits ready.
For a while, the 1,2,3 coin indicators were working, but after shuffling the 6821 chips, I still have most of the machine working, but the indicator always flashes the 2nd coin now.  Can't seem to send power to the handle release solenoid, but with coins in, if you release the handle manually, the game will cycle, and pay off if appropriate.  I think the next move is to try and get a set of working 6821 chips and replace all that I have here.  Not having a lot of luck locating them so far.  Can't tell if my current problems are mechanical, or just missing a signal from a failed 6821 IO chip.
Starting to think that there may be some hope.  Still not electocuted, but working on it.
   Keith

[stayouttadabunker]

wutsit4 ,
You dig around on boards more than I do! LOL
Can I see a picture of your machine and board?
I'm not sure what an IGT Esprit is?
Thought I really wanted to buy a Lotus Turbo Esprit when I was younger!

[wutsit4]

Thanks for the response.  I wish I was better schooled on what I am trying to fix.  The machine is labeled as an Aristocrat, and has IGT on some glass and trim.
I think its from 1982.  Ordered some new 6821 chips late last night.  Also ordered some 5101 memory chips, as they come highly recommended and referenced by op-bell.  If I don't need 'em now, I probably will later... better to get them while I can.

I wonder how to find out which transistors control which functions.  If I still have issues, after a fill up with "new" Input/Output chips, I guess it'll be transistor time.  Guessed that the smaller transistors handled the display, and followed traces back to two of the 6821s.  Putting functional chips there, got the displays to work.

Next post has board pictures.
   Keith

[wutsit4]

I have 2 of these machines.  These are the boards that are not installed.  The I-O board is nearly identical to the one I am using.  This game board is in rough shape.  The one I am using has new batteries, and is in much better condition.  This will give you an idea of what I'm working on, but my "good" boards are in place now, and I don't want to pull them, as things are nearly working.  I'll try to get some pics, the next time I have them out.
Thanks,
   Keith

[stayouttadabunker]

The traces down around the bottom left hand side of the board near the blue battery area...
Are they all intact? Non-broken? They do not look too hot.

[wutsit4]

They don't look too good.  I have not even tried to run this board.  Need to clean it up, and add some batteries.  First I need to get the machine working with my clean boards.  If I can clean up this board, I'll have a spare reel set that matches this board, and all the glass and lighting to change to a 5 coin, 5 way.  Otherwise, it's just more spare parts.
   Keith

[wutsit4]

Had the bright idea to bend a paper clip to hold the handle release solenoid in the released position.  Machine will only cycle if a deposit has been made, even if the handle is pulled.  Lubed up the reels.  Closed the door.  Gave my wife a small bucket of coins.  I'm amazed.  Still needs some 6821 chips to handle a few lesser functions, like displaying 1,2, or 3 coins in, but overall, I'm amazed.  Thanks for all the guidance I received from this forum.  I think I impressed my wife with this resurrection.
   Keith

[stayouttadabunker]

I believe you're on your way to a full slot addiction restoration! 
I truly think that part of the fun is getting it to work the way you want it to.
At the same time, you learn tons and tons about your machine!
But by posting everything up here - we will all learn too!

[Op-Bell]

Congratulations Wutsit, it looks like you've had a VERY productive day. 

For finishing off the rest, can I draw your attention to the "Esprit Wiring" PDF file? Once you've identified the diagram for your machine, you'll see the left column tells you what connector and what pin, the "Loom" column tells you what it does, and the far-right column headed "Driver PCB" tells you exactly what pin on which 6821 chip it's connected to. That should be a useful guide in figuring out what 6821s need replacing.

[wutsit4]

We got a fair day, (a few hours of run time), out of my efforts.  My wife was playing, and the machine failed to cycle.  Display was still lit up, but no spin.  Turned it off... waited a few minutes, turned back on... reels would not home.  Kept turning the cam rod.  Displays did not light up.  Coin mech did not activate.

May have gotten the last hurrah out of my over tired 6821 chips.  Hope to receive the replacements soon.  Ordered from arcadechips.com.  Could get the reels to stop at "home", by pulling the handle while they tried to reset.  Still had no display.  Shuffled my 6821 chips around some more, buy no joy.

This machine has a large "tone generator board" mounted horizontally just above the hopper.  Looks like the volume control is physically broken inside.  Don't know if the board is bad, or the volume control is shot.  When I put my hand on the volume control, I could hear the radio faintly through the speaker.  Maybe the amp is working, but I am losing the signal at the bad volume pot.

I'll be out on the road this week til Thursday.  Hope to have some more 6821s to blow up when I get back.  I'll also try to find a replacement 10K volume pot that fits the board and connections.  It was fun while it lasted.  Considering these were commercial machines, I'd like to think that if I fix it again, it would run and be stable for a while.

Thanks again for all the support.
   Keith

[wutsit4]

Made it back to town this evening.  Big surprise, my chips were already here.  Thanks for the quick service to "arcadechips.com".  The chips looked good, the pins were straight.  They popped into the board, and it looks like everything is working, minus the sound, as the sound board is on my bench awaiting more parts.  Probably should have ordered some extra spare 6821 chips, as that seemed to be the part that took this game out of service.
Thought this project was beyond me, but it looks like I need to go to the bank and get a few rolls of quarters now.  And to think that I have only owned this machine for 10 years, and could never get a handle on what was wrong with it.  (Power supply, processor board, wiring harness, missing parts, bad connectors, etc).  Could not have done this without your assistance.

I am guessing that the hole in the base of the machine is for the change to collect in when the hopper is finally filled up.  Is this hole in the same place on all slot machines?.  Before I cut a hole in the top of the stand that is holding the machine up now, is there a "standard" cut out in the top of a slot machine stand?  If so, is there a locking compartment in a slot machine stand?

Anyhow, thanks again for all of your help, and I hope to be in touch again, through the forum.
   Keith

[Op-Bell]

And to think that I have only owned this machine for 10 years, and could never get a handle on what was wrong with it.  (Power supply, processor board, wiring harness, missing parts, bad connectors, etc).  Could not have done this without your assistance.

Good work, congratulations!    Troubleshooting these old games is a learning process for everyone - your experience and efforts will help the next guy. Thanks for sharing it here.

[wutsit4]

Greetings,
Don't know if I should start a new post as I continue to debug this machine.  I'd like to ask a few more questions...
Do we know approximately what impedance I should find on a handle release coil, if I just check with my ohm meter?
This is not working, and the release is held back with a bent paperclip now.  I am guessing it runs on 24 volts? AC?

Has anyone seen a soundboard like I am showing below?  I had to replace the volume control, but could not find a direct replacement.
Just temporarily jumpering it to the board for now.  If I put my hand near the unshielded volume control, I can hear a radio station
through the speaker.  I must be a fine antenna.  I can control the volume with the volume control, so I think the amp is working.
I am not getting any sound generating from the board.  It hooks to the machine with what I believe is connector S19.  It also has a
ribbon connector that seems to go to the small board by the mechanical coin and play counters.  There is a large edge connector on
the board, but it is unused in this machine.  The board is called a "tone generator module" dated 1983/IGT.

The large NEC chip next to the "program?" chip gets very hot, pretty quickly, radiating heat from the center of the chip outward.
I am guessing that is not good.  There are no chips in sockets U6 and U10, but there are in the matching U7 and U11.  Do we know
if I need to get more chips, or if this is a valid configuration?

This has been a very interesting, and often frustrating project, but all things considered, I'd rather be working on a mechanical
machine, where you can see what is going on.  Thanks again for all your help, and we are having a lot of fun with the slot machine.

   Keith