interesting thing i learned yesterday that most of you probably already know...

the coin door/frame on my jacks open (1977 machine) is pretty mangled around the lock area (not to mention "bent out" around the edges making it very difficult to open/close), so awhile ago i bought a used door/frame to replace it...

the door came with all the coin mech stuff and wiring harness, so i plugged in the harness to test it, pushed the start button, and the machine fired up... figured "piece of cake, just slide the replacement assembly straight in"...

wrong...

the door is from a 1976 machine... front of door is "flat" with no label vs. having a convex ring where the label goes on the existing door (figured this out from ipdb pics, so there could be a crossover on the years)... no biggie there, not overly concerned about having the "right" door...

the "showstopper" difference is the harness itself...

- the one on the 76 door is shorter (by quite a bit) than the one on the 77 door... when the harness wire bundle is held in place by the plastic clips on the cabinet, the door will only open a little bit, since the harness is not long enough to allow the door to open all the way...

- the harness seems to be wired differently (even though both are wired for 2 coin entry)... coin entry switches do not add credits with the 76 harness, but do with the 77...

i ended up scavenging the 77 harness and using it with the 76 door... and now all is well...

again, most of you probably already aware of this, but figured i'd post it for other "new guys" like me who may be having a "wtf moment"...

since i'm sitting on an endless conference call and am bored... perusing ipdb pictures, it appears as if "surf champ" was the last "flat door" one, and "volley" was the first convex ring/stickered one... so the switch occurred in august 1976...

it also appears as if the "red coin insert slot with the paper insert" vs. "white coin insert slot with the sticker" was phased in when they switched to the big door... machines up to "royal flush" still had the white insert, "card whiz" and following machines started using the red one... since the replacement door had very crusty white inserts (indicating they had never been changed), i'd hazard a guess that the donor machine was a "royal flush" or earlier..

none of this sheds any definitive light upon the differences in the harnesses... something tells me that may have to do with the way the machine adds credits (i.e. can be set up to give 3 plays for 2 coins), requiring a different wiring circuit than a machine without the "2 coin" option*... short of looking at the labeling in the pricing jones plugs in individual machines, i dunno of any way to figure out what machine it was when the pricing options changed... possibly it was when they switched the inserts, that would make a bit of sense...

* actually, this would be a bit of a throwback to the old "2 nickles for 1 play" circuit that went away when pricing went from "10 cents/1 play and 25 cents/3 plays" to "2 plays for a quarter"...

@steve... you are welcome...

@bert... my curiosity got the better of me, so i had to sleuth it out... hopefully the data set i used (ipdb pics) is as reliable as i believe it to be...

i remember that 2 people on the call were throwing each other under the bus... that's always fun when i'm not the throwee... other than that, not much...

further thoughts on the harness...

i'm starting to feel relatively confident that the difference in harnesses (wiring wise) is due to the pricing circuit/logic... the JO has a supplement schematic for the coin chutes... a cursory glance at that shows a "3 for 2" circuit with "different" wiring than the harness that was on the flat door...

still unsure as to when the "3 for 2" pricing was implemented; if someone has a "card whiz" and/or "volley" (or schematics), i'd be curious to see what the pricing logic is on those machines, given the external changes starting with each of those... of course, there may be no correlation there at all...

following up to bring closure to this... once more, i am reminded that correlation does not imply causation....

it's not the wiring harness... it stopped working again today with the so-called "correct" harness...

what it really was... there was a really sad solder joint on the step-up coil on the credit unit... when i switched the harness, i must have jostled the machine enough to make enough a "good connection"... after some play time, it jostled enough to break the connection again... after re-soldering the joint, it works correctly...

another lesson learned...p

however, it doesn't change the fact that the harnesses are different lengths...