Williams Strato Flite Reset Issues

[Strangeways]

I've been restoring a Williams Strato Flite and it is 99% done. As per usual, there were several issues involved in this restoration, that were repaired along the way, but it had a problem right from the moment I switched it on and had it playable.

This game is the last of the Williams 4 Player EMs, so the Pinrepair guide, and the very useful Steve Fury Video does not relate to this machine 100%.

I need a new set of eyes on this game as I've gone over and over this machine, and I'm sure I've missed something simple. The schematic and manual are here ;

http://www.ipdb.org/machine.cgi?id=2398

Here's the issue. Game works 100% perfectly with all functions working. but it has an annoying reset issue I cannot work out. With Credits, press the credit button, all the score reels reset to zero perfectly, and the bonus unit decrements perfectly. Then the trouble starts - the RESET RELAY "sometimes" stays on, which keeps the Score Motor going, and the Reset Relay remains on via the score motor. so it is stuck in this loop of infinite resetting. The 1-2 Reset Relay and 3-4 Reset Relay keep pulsing the score reels, but they are already all Zeros. The Bonus unit decrements, but it is already reset.

Three associated paths keep the Reset Relay on ;

1 - The 16 Zero switches on the score reels.
2 - Score motor INDEX B
3 - Bonus Relay Switch

WITH

Any of the above will keep the Reset Relay on if the Reset relay hold switch is on. Once it is held on, it stays on until the path is broken by ALL of the 3 methods above. To break the cycle, ALL 16 zero switches need to be open, the Score Motor INDEX B needs to be open and the Bonus Relay switch must be open. All these conditions are met, yet the Reset Relay remains on and keeps the score motor running until randomly it breaks the cycle, advancing the Bonus Unit X 1 and then the ball is served.

In theory, a very simple circuit. Bit it is intermittently not working. It might work 100% once in 10 games.

The score reel zero switches are adjusted with no short.
Score Motor INDEX B is adjusted correctly with no short.
Bonus Switch on Bonus Relay is adjusted with no short.

The alternate path is via the Coin Relay and Game Over Relay. This is what switches the Reset Relay on during a credit or coin. These are both open paths.

Although the game is still playable, it is still very annoying that I can't find the source of this minor issue. I'm hoping someone can have a look around the schematic before my eyes pop out !

[Retropin]

Aaah yes WMS games.
Im willing to go out on a limb here and tell you where to look to fix this as most likely its the only place you haven't looked.
My old Travel Time used to do the same thing.. continually reset when all conditions were correct.
You have a short, you know that but it isn't on the switches.. so where is it?

The loom on a WMS is normally attached to the back of the machine and its a flaw in the design as each time you lift the PF, the loom rubs against the edges of the cabinetry. I eventually found my fault at the point on the loom that rubs against the timber.. you end up with very small breaks in the insulation and because all machines are kept HI waiting for LO... it grounds itself.

Worth a look mate as ive fixed 2 WMS machines with head scratching issues because of this. The Travel Time was easy as I could see a tiny spark on start up when looking through the coin door. Since then, ive always regarded this as WMS' Achilles heel

[goodolddays]

I still have one , and have had a few WMS EM's but never had this problem .
Will keep your suggestion in mind for the future though Gav . Thanks for posting it !

[Strangeways]

After stepping away from the game for 2 days, I started from scratch and the problem seems to be fixed.

The Bonus unit has two sets of switches that govern the END of the reset cycle ;

One set of switches runs the score motor. These switches were gapped too close. So the motor would not have time to "brake". Possible issue.
Second set of switches is the "in hold" to the bonus relay - basically keeps the relay circuit "on" until another switch or the score motor breaks the circuit. These were gapped too close.

Given both "normally open" switches keep the reset cycle going, were gapped too close, the vibration of the 115V reset coil may have caused them to go open. Hence the intermittent reset cycle. The reset coil is mounted in the vicinity of the Bonus relay (the culprit).

EMs can be incredibly frustrating, but usually a clear and logical approach coupled with an understanding of the schematic leads to a successful repair. Sometimes you just need to walk away and think of something else !