Hi guys,

This is a old problem that has plagued this machine since I took possession.. I started a topic on this awhile ago but I have lots of new info to share and a video so you experts can see the problem actually occurring..

While playing a 5 ball game.. the G relay is supposed to lock on after all the pins are knocked down the first time.. This happens as advertised, however.... While the G relay is locked on anytime I start hitting a flipper either side or both at the same time, the G relay will randomly unlatch for some reason.. The troubleshooting I have done are, adjusted all the switches on the G relay so that I get that nice crisp click when it latches.. all the switches are clean and I replaced the actual locking switch on that relay as well.. I also replaced the relay plate and out of desperation I replaced the relay with a new 9740 I had lying around. As you can see from the video, it only takes a few hits of the either flipper to unlatch the relay. If you look close you can see the relay bouncing randomly while I hit the flippers, then it just unlatches all together.

When I put the game on 3 ball the relay is latched from the get go but I can see it bouncing and trying to unlatch but it just gets re-energized so fast it never unlatches fully..

Also, as you can see, no scoring , the score motor isint running and nothing else is happening.. just a flip of the flippers and boom.

Ok please let me know what you think.. I am about to pull all my hair out of my head trying to figure this one out. Thanks so much.

Hi Howard, So I checked the switch again and cleaned it, adjusted it and then tried it with the same results. I just finished replacing it with a brand new switch as well with the same results.. Its like some power fluctuation is making the switch unlatch.. any other suggestions? Not sure if you watched the video but you can clearly see the switch locked in and then just loosing power

It actually just masks the problem on 3 ball. When on 3 ball you can still see the relay jump and try to unlatch but the powered circuit just re latches it so fast it cant release all the way.

also is int 4c a normally open switch? in the video i am actuating the G relay manually..

Ok thanks.. I did check 4c and the switch is clean and gapped correctly. Not sure if that could even be a issue since im manually laching the relay by hand but I wanted to eliminate that potential as well.

First Thank you to Runbikeskilee , HowardR and Cash_Riprock for those last replies to this thread.. I had to wait 24 hour before I could post again due to verification.. anyway.. I will try to make this as clear and concise as possible based on everyone input.

1) the G relay lock in switch (5A) is brand new, clean and adjusted properly. All solder joints look good and clean with no breaks that I could see..

2) I jumpered everything in the circuit with basically the same results.. Jumping all the following directly to 5A on G produce a bypass and makes G lock on..
a) 6th and 0 position switch,
b) the R relay make side of the make or break switch,
c) 15v power direct from the fuse thus bypassing the bounce switch,
d) the bounce switch itself..

Like I said, all of these produced the same results.. G would lock on and stay locked on...however these is a interesting thing to note here.. While direct power is supplied to this switch, as I use the flippers, you can see the G relay trying to unlatch.. ( slight little momentary bounces on the switch) but because its getting direct power it just re-locks very fast causing no dropout of the G relay.. This is the exact same thing that happens when the game is on 3 ball play as well..

There is also another interesting thing to note here which makes this all the more suspicious of some type of short somewhere.. While G is locked on, I can manually open the make/break on R to cause G to unlatch, but this is sporadic at best.. sometimes it wont unlatch at all and sometimes it will.. but if I latch relay H ( special completed relay) at the same time as G, H will always drop out perfectly while I open make/break on R, but G will sometimes stay energized and sometimes it will unlatch like it should..

This is just all very weird and I think it may just be above my skill set.. Im thinking of just giving in to defeat, putting the game on 3 ball play and calling it a day.. Unless someone has anything else I can try.. If you need a video of anything let me know.. But for now, I feel like this issue has finally gotten the best of me..

I hope all this info makes sense.. Thank you all.

i think the pops will cause it too but not nearly as often..

yes they all look good to me..

ive tried shaking and smacking everywhere and I cannot get the coil to drop out.. its ok on the pics,., no tabs touching or anything it all looks very clean to me.. but it seems like there is a short somewhere

pm sent thank you