Jet Spin
Gottlieb, 1977OK, so re-attaching the wire to the PU got the high score AAB bonus going but it still wants to add credit. The knocker, until I disconnected it, would hum when the bonus score was reached and the "Y" (add replay unit relay) is pulling as well. I don't see any shorts or crossed wires; any ideas?
Well, I guess this is every player's dream: now it's giving credit AND an extra ball at the score bonus.
Quoted from currieddog:It's the credit, but where? and how does it do a high score bonus if it's not connected to the PU?
Huh?
Quoted from pinhead52:yank the jumper that sets extra ball versus credit. this will tell you which side of the jumper the short is
From pinhead52, Howard. But I don't think it's at the credit/extra ball plug.
Quoted from pinhead52:yank the jumper that sets extra ball versus credit. this will tell you which side of the jumper the short is
Quoted from currieddog:But I don't think it's at the credit/extra ball plug.
pinhead52 's suggestion is part of the diagnosis. At the risk of stating the obvious, the credit/extra ball plug is hooked up to other parts of the machine. The next diagnostic step is to narrow down which other part has the problem.
Yes, but if the plug is not inserted in the credit/extra ball plug and it is still giving credits then it has to be coming from somewhere else. Seems to me that the high score/bonus info is going from the PU to the Add Replay Unit, but how? I don't see any crossed wires, etc.
This is actually a player's paradise (if it wasn't already set to free play): you get extra balls AND credit for high scores, and even credit from playfield extra balls, and I just tested it with the match feature in and it still gives extra balls! Kind of amusing, though the oddness bugs me.
Quoted from currieddog:Yes, but if the plug is not inserted in the credit/extra ball plug and it is still giving credits then it has to be coming from somewhere else. Seems to me that the high score/bonus info is going from the PU to the Add Replay Unit, but how? I don't see any crossed wires, etc.
so you tried it?
ok.... still awards credits even with the plug out... the SL+GR also goes/comes from the W relay and the YEL+GR comes/goes to F relay. They are on the same Jones plug bottom board to head... if they are side by side, look for a short there...
Do you think it increases the game's value? 
It's pretty weird, but doesn't affect play. I'd still like to know where exactly the cause is though.
Diagnosing things that shouldn't happen is harder than diagnosing things that should happen but don't. With that said:
After looking at the schematic for a while, I see that there's a Slate&Green wire that connects these 3 things:
1. The Extra Ball / Credit adjustment plug
2. The 15th Position switch on the Credit unit with a Blue&Black wire on the other side
3. A switch on the 2nd Chute (W) relay with a White&Orange wire on the other side
The first thing to do is make sure the replay pulse is coming through the Slate&Green wire by disconnecting the Slate&Green wire from #2 & #3 and running a jumper between those teminals. If that resolves the problem then solder the wire back and continue to the next step:
#2 is in the backbox. Next steps are to look at where #1 & #3 are, and draw a picture of exactly how the wire(s) connecting those 3 run through the machine, including any Jones plugs. Let us know what you find.
Before I start disconnecting things, here's a shot of the SL-GR at the 15th pos. sw. Note the bent switch leaves, which I guess is for free play? How might that be affecting things?
Location, etc: "W" is on the bottom right of the cabinet, along with most of the other relays. SL-GR comes up into the backbox via a Jones plug, and connections there are good. The adj. plug is in the backbox right next to the credit unit.
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Springfield, MA