Hi,
I picked up a beat up Grand Slam a few weeks ago and have managed to get it running but I need some help.
The cockroach's have called it home for the last 20 years and `they have devoured anything made of paper...if anyone has some info regarding the size of the four fuses and what the switches do that would be great. Also, what size rubber is needed that goes around the back of the roto targets? The one I put in allows the ball to get stuck. The ball also gets stuck down one of the side lanes which is a bit weird. Anyway, the bumper's work now after I replaced the metal plate which had dislodged from the rods, the roto target spins but doesn't score, the lanes don't score either and one of the flippers gets a little stuck. Everything else is working well though the ball usually takes a few tries before it's ejected. Any help, especially with identifying the mechanics and fuses would be great (240v power here...not sure if that changes the fuse amps)

Thanks guys. It nearly ended up as a coffee table, and I couldn't let that happen. It was originally from Cairns where I grew up so there's a good chance I played it as a kid!

Thanks for going to all that trouble pinhead 52. Sorry to be a pain, but do you know the amps of the fuse near the transformer?

Thanks Jodini, I'll check if that part is bent...that makes perfect sense!

Anyone know the amps of the fuse nearest the transformer? Is it a slo - blo fuse?

Thanks Dirtflipper!

I bent the arm a bit and it seems to work well delivering the ball to the shooter lane.
I took both flippers out as they were gunked up and sticking and now they're all good.
I just need to figure out why none of the lanes register points, and the standup targets and the roto targets...are they all controlled by the same coil / switches? The scoring's a bit off too as I seem to be getting too many runs and way too many points.

I noticed today that the triple relay locks on and gets quite hot. Still no scoring on any lanes or roto targets. Reels aren't resetting either??

Gaps are all good...there's a click from under the playfield and no score registering.
It's not just one rollover, it's all of them plus the roto target that's not registering...

Had a good look at the motor...all the gaps appear correct and have been cleaned. It's quite erratic with the 5inch bell going off at random times like when the ball hits the bumpers and the slingshots...weird.

No, the bell doesn't ring if you bang different parts of the playfield.
When you go through the the triple rollovers the triple coil locks on and all the other rollovers don't lock coils on but don't register points either.

I think you're spot on as nothing run related is scoring properly and that's the one unit I didn't really rebuild. I actually wasn't sure what it did to be honest!

I hope mine's not that badly worn...there doesn't appear to be too much wear that you described, but I'll get in there and have a good look on the weekend.

I also noticed a wire that has come off the rivet head, but it's on the unit in the headbox. Maybe something similar has happened on the hit unit?

When I started fixin her up, I cleaned all the little contacts lightly with 1200grit sandpaper and got rid of any grime with methylated spirits. The coil has power and smoothly turns the wheel. I cleaned the switch also but I didn't take notice of the number of advances. I did notice the switch was opening and closing well. How do I tell if it's in the neutral position besides the switch being open?

I really appreciate the help, I spent ages cleaning, rebuilding etc etc and thought I had everything sorted, but it's proving a bit of a challenge. I've never dealt with the roto targets before and haven't come across the hit unit either. I tried playing it today and still get the bell instead of the chimes and now I've only got the flippers working!

I noticed that one of the hit unit switch contacts was badly pitted so I filed it smooth, cleaned the terminals again and now when I start a game the scores all zero'd (yay) but the score motor continues running
I still think I'm on the right track...

When the score motor runs, the relay for the 'tens' 'run' score reel locks on. I checked the reels and switches and they're okay so I checked the playfield switches which all appear fine. I'm not sure what else might be causing this...any ideas?

Me too!

I'll keep looking for that stuck switch. I was thinking it had to be something that scores a 'run' but so far, nothing.
Good luck with the remaining issues with your machine.

Nah, that was the first thing I checked...still have those 'runs'

When I could start the game and the ball went through the 'triple' lanes that relay would lock on. Since 'tinkering' with the run stepper, I just have the score motor running so unsure if it still will do this. Now it's just the 'tens' run score reel relay that locks on.

I cleaned and gapped the contacts and the reel zeros everytime I advance it off zero, but then the relay locks on again. Perhaps it's in the roto target area which is where I'll look next.

Any suggestions would be appreciated as to why the second reel of the 'run score reel' is locking on.

Shorting each pair of contacts didn't do anything. I disconnected the playfield & the motor still runs, so it's not a playfield switch. While the score motor continually turns I can manually advance each reel to 1 and it will spin round to the zero position. The Z relay remains locked on the whole time.

I guess I'll check all the relays on the bottom of the cabinet & in the backbox again in case one's not adjusted properly.

I'm not sure how to 'jumper' the zero switch?

Thanks Jeff.
Still, the z relay is locking on. I'll check the 'v' relay & the 'vb' relay(if I can find it) & motor 2b.

I haven't got the schematic. The Z relay is on the far left in the backbox.
I have the startup sheet that states;

When V relay coil is actuated it is locked in by the armature of VB coil (had cockroaches eat all the paper labels so not sure which coil this is.)
A switch on the V relay closes and actuates the Z relay
Thru closed switches on Z the point score and run scores reset thru switches on motor 1A & motor 4A.
When all reels reset to zero motor 2B makes, VB relay is actuated.
This releases armature on V relay and opens the switch that actuated the Z relay.
Reset complete.

So, if anyone can pinpoint the VB relay, that'd be good.

No, thought someone with a Grand Slam might have had a similar issue.
I've isolated the fault to the cabinet board. I disconnected the playfield and the motor kept running, then I reattached and disconnected the backbox connectors and the motor kept running. I think it's a switch on the score motor as that was the only thing I touched after I had it working last. Except they have all been cleaned and are working correctly??