Skylab
Williams, 1974have two issues: 1). Replaced ball return coil...now nothing. original coil was humming and hot but at least was getting juice. 2). 100 reel resets on power up, but at game start begins constant engagement. Cannot find anything amiss with contacts on 100 relays. Mb i just missed it.
1. Check SM 4A 2. The 100 reel just keeps running? If so, check for stuck RO switch, etc.
Do you have the schematic? If not: http://www.ipdb.org/machine.cgi?id=2202
Quoted from Tipkid:Replaced ball return coil...now nothing.
Assuming you mean what the schematic calls Ball Release, is the Outhole relay energized?
Quoted from Tipkid:100 reel resets on power up, but at game start begins constant engagement.
Is the 100 point relay energized? If so, the usual cause is a stuck switch on the playfield.
Quoted from Tipkid:Cannot find anything amiss with contacts on 100 relays.
Didn't know you had that many relays. Haha
Thx..found the stuck relay...Lol dumb me. since im just a layperson when it comes to Pinball machine im not real up on the technical jargon as to parts etc. My dad used to buy broken machines for $10 etc when I was a kid and I just figured them out. So not an electrician can cant read a schematic, but the electromagnet machines are just a series of contacts so i just figure it out the hard way.
Well dont quite understand "energized" but Im assuming it means getting some juice. When the ball enters the outhole nothing happens. There is no bonus, no ball advance no ball release. I have everything else up and running but this. I do have one other issue. The Credit Key Switch in the backbox advances 5 games when you press play instead of reducing by 1 game and it also advances 5 games instead of 1 game when manually adding a game. Either way the Credit Key switch is in a giving mood like Welfare. Any ideas?
Howard, got outhole up and running after adjusting cleaning ball count switch.. 
. the one last issue I have is the Credit Switch. it continues to add 5 credits when starting a new game or when just reloading the credits. Credit switch is not subtracting credits on adding to them
Are you set up for free play?
On reading schematics: my big initial problem was looking at one as a literal physical map, rather than something that shows connections. So, if you go to the link above and open the schematic you'll see that the 6v. side on the left, which has the yellow wire as a dividing line, shows the lights, etc. Go to the right side and find the relay you're interested in, in this case the Ball Release, and track it back and you'll find the NO (normally open) switch at 4A on the score motor, and then a tie-in from the M/B (Make/Break) switch on the Outhole relay. Those are things that are involved in energizing (getting power to) that relay. Wire colors are there, with a list of abbreviations as well, and Williams schematics are great because they show the whole score motor. Keep working at it and all of a sudden you'll get it.
Quoted from Tipkid:Howard, got outhole up and running after adjusting cleaning ball count switch.. . the one last issue I have is the Credit Switch. it continues to add 5 credits when starting a new game or when just reloading the credits. Credit switch is not subtracting credits on adding to them
Sounds like your 25 cent adjustment jack is set to give 5 credits per coin, and it's operating correctly.
Or 6.
Tipkid, here's some good reading: https://homepinballrepair.com/
I'm getting there!!! Have one last problem unsolved...Looked at schematic and I think the game relay is what I'll refer to. On my unit there is a red "game start" button on front of unit. When I depress it, it resets like normal, but it adds 5 games to credit as if I put a quarter in the slot. So If i put a quarter in slot for 5 plays when I press the "start" button it adds 5 more credits to 10 credits and starts game as normal. I cannot find out why the game reset button is adding credits it should decrease by 1 credit.
Check your "25¢ Adj. jack," which should be on the bottom front of the cabinet, and see if it's set for 5 or 6. Then check out the switches on your credit unit (backbox, where the credit reel is) and make sure they're clean and gapped correctly. Also, with the power off, make sure that the coil that subtracts is working ok, by pushing the plunger.
There is really no natural path for the "Credit button" switch to not only start a game but also to add credits.
As was stated, it sounds like:
1. Someone has modified the game so that the start button also connects one of the coin door coin switches.
2. The 25 cent adjustment jack is set to 5 credits per coin.
Look around the wiring at the start button as well as the Jones Plug where the coin door harness plugs into the cabinet. Look for non-factory looking wiring (plastic coated wires, wires not contained within the Catgut wraps etc.).
Looking at the schematic again, it would also be very easy for someone to have added a jumper wire from the lug on the Coin Relay coil to the lug on the 25c relay coil. This would cause the start button to start a game AND pull in the 25c relay for multiple credits. So, you may want to start your search there.
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Springfield, MA
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