This is a Gottlieb Black Hole machine.
So the GI lighting, is operated by contacts on bottom left of upper play field. (blue, purple, purple)
contacts open lights go off, contacts close lights come on... but I have continuity between the bare wire that connects the bulb sockets and the bare wire that is stapled to the board...(reading through the transformer?) and I have voltage on both wires (bare metal wires) when the contacts open and the lights go out, I still have 2.XX ac voltage on what should be ground, voltage drops out when the contacts open on the (blue, purple, purple)...
Now with my meter set to dc volts I have a constant 7.9 v dc on the blue, purple, purple... and the same dc voltage on what's supposed to be the ground... this can't be correct.
I'm thinking that the 2.XX volts ac on the "bare ground" wire is actually the ac return to the transformer, and the diff between the 7.9 v ac and the 2.XX is the resistance of all the bulbs together... ( all led's by the way) am I thinking right? I'm just still wondering why I have dc voltage readings on these wires.

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well I was going to retype that with a quote... anyway yes they are touching...

so I removed and re routed, separated the bare wires...

it was me, I did a play field swap and didn't realize that some were ac and some were dc...
so should I have continuity between say the door as a ground and all the bare wires that I just separated... including the GI common bare wire?

Okay so I went up both sides and none of the bare wires are touching each other

FOUND IT lower pic staples were touching thanks for the help on this
Merry Christmas

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didn't see it till i looked at the pic lol

Now onto the next issue (s)

Thank you wouldn't have found it without you
now onto the next issue (s)
that problem actually fixed a few things but now I have others.. lol

think I may have damaged something having those return wires touching... I did get two of the 4 pop bumpers working, have a rebuild kit (5) coming from big daddy so hopefully i can get those working... plan to swap boards to see if it's a board issue or not.
issues since the bare wire incident...
one of my top lane roll overs isn't registering (far left one at top)
top stand up target isn't registering now
roll over switch for gate isn't working... (ball return gate to top pf)... I need to verify that one, don't think it registers...
neither contacts register on both sides of play field, down by the flippers
the ball capture hole isn't doing anything now either... doesn't register the ball in the hole and no kicker.
also blowing the fuse for the "black" drop target bank... disconnected wires at fuse holder to determine which one was blowing it.

everything on the lower works, not sure about the capture hole though... if top stuff doesn't register, not sure this ball will kick out.
also before the bare wire thing the "ball to upper pf" coil has an issue... not firing at all. I put my meter on the coil and it doesn't appear that any power is even going to the coil to kick the ball to the top. need to check that for sure though... I may have had meter leads wrong (diode) lol

was thinking about the transistors mounted to the bottom of the pf... not sure
both my boards are ni wumph and not sure if there is a way to use them for troubleshooting, there are lights for diodes but I can't find any specs on these boards.

if you have any ideas about these that would be great, if not I bought some more fuses and I guess I'll be doing some meter work tonight through Tuesday lol 4 days off for new year lol hope to get this thing working in the next 4 days but it's been sitting waiting for the upper pf for the last 5 years so a few more weeks wont kill me lol

great plains electronics has the transistors I need but they are closed until wed I guess...
I need to check those to be sure the gate is working... thought about replacing them anyway (1981) lol
was also going to re-pin connectors in the head this weekend also... need to order more of those from GPE when they open, but I have enough to get some started

somehow these were both reading closed, so I pulled them out, adjusted them and now they both work

---roll over switch for gate isn't working... (ball return gate to top pf)
this works but doesn't open the wire form because the top stand up doesn't register... the roll over part is working though.

---one of my top lane roll overs isn't registering (far left one at top)
---top stand up target isn't registering now
no diodes there...

got the pop bumpers working... re flowed the pins on them still hang just a bit but the rebuild kits should fix those...

on the "black" drop targets the red, black, black wire has continuity to ground... with that wire landed on the coil I have ground on both legs of that coil... blowing the fuse. if I disconnect plug number a9-p3 everything at the coil is fine... so I have a ground issue from the plug to where the hell ever it goes hahahaha back to the drawing board... getting closer though.

so drop target coil wire red, black, black is wire number 200 everything I can find in the manuals lists nothing for plug A9-P3 but wire 200 should be a 12 vdc + (pos) I have cont. to ground with that wire..
it goes to my driver board J4

yep blown mosfet on the driver board

or are they the double stacked in the pic
the stand up target wire goes to the top set on the lower board

OKAY checked against the others and it reads the same...

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found it...
everything works now except for the drop target "black" bank... but my mosfet is shot for sure so I think as soon as I get that fixed I'm good...
oh and the lower ball kick to the top coil something is still going on with that but everything else is good

thanks again for all your help...
looking at the diodes for the stand up target that bare wire was running right under that assembly... moved the wire over and all working now

oh, hell... you helped believe me... wouldn't have pulled that board out and found that dang wire if not for looking closer at that diode... I metered them all in place and I know that's not how you check a diode... so I thought okay im not going to be lazy I will isolate it lol well in doing that was when I found the wire. I still de soldered and checked it, and it was good.

ya so I am getting power to the flipper thats inop so I think the coil is gone I can isolate that and check coil resistance.
also the lower kicker is not getting power to the coil, so I need to find out where that comes from...
the only other thing that isn't working is the drop target "black" bank.. and that is for sure that mosfet...
spent about 8 hours on it tonight... got home early for a 4 day weekend so from about 3 pm till 11:30 or so I was all in lol

so all in all, we got a lot fixed thanks again

I think I saw this a long time ago, when my machine was in pieces... now that it's back together, I'm reading through this... wow, there is a lot of good info in here... thanks for that link, I've downloaded it and am reading through it now.

no pull up resistors, so I need to do those.

was looking for the transistors, that manual says it should be a 2n5875, and needs to be replaced with a 2n5879... mine has the mj2955g installed, so I would assume someone replaced all of these but it doesn't seem likely to me... GPE has the mj2955 transistor, not sure what the G designation is.
also was looking for the caps for the rubber kicker coils... says you need the 2.2uf or 10 uf at 100v can't find any of those either all day long in 50v though.
FOUND EM' hmmm old stock though... would there be an issue with them drying out if they haven't been installed?
https://electronics.stackexchange.com/questions/8794/do-electrolytic-capacitors-have-a-limited-shelf-life
ebay ebay.com link: 2pcs 2 2uf 100v Axial Non Polar Capacitor 100v2 2uf upgrade 63v 50v NP

didn't you tell me some place else you can order components from? can't seem to find that post now.
WOW, now that I look ebay has better prices than great plains lol maybe I'll do that hehehe didn't even think about looking there

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you know these looked okay till i put the new pins in lol

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