Westland, MI
Let’s start with the easy part and check continuity between the switches they are connected to. If one switch is out and the column are good, it’s more than likely a wire
(Topic ID: 267534)
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Monte Carlo
Gottlieb, 1987
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Quoted from Chisel:Hi there, I didn't read every post but if your ramp is still not working it could be the 2N5879 transistor that's under the playfield between the flippers right at the bottom of playfield under the apron. This fixed my non working ramp. If it's bad here's a replacement: https://www.greatplainselectronics.com/proddetail.asp?prod=2N5884
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That was the problem. I had fixed it a few days ago. I appreciate the info.
Quoted from Bax1:Let’s start with the easy part and check continuity between the switches they are connected to. If one switch is out and the column are good, it’s more than likely a wire
I have circled what is not working and found them on the schematic. Any ideas?
Inkedc89673c3b1ed360f74a83dec90708c77b331d2c6_LI (resized).jpgQuoted from Bax1:Ok so check the top right pop bumper and make sure it is working. if that is not working that whole column is out and we need to trace it down why and where it would go.
so the bumper works as it should
ok if the pop works, i would start with continuity test going from one end of the wire to the next. not sure if they go to a connector or go straight to the board. good thing is you have the color decoder there to tell you what the wire is. so like sw 31 is brown.
Quoted from Bax1:ok if the pop works, i would start with continuity test going from one end of the wire to the next. not sure if they go to a connector or go straight to the board. good thing is you have the color decoder there to tell you what the wire is. so like sw 31 is brown.
I am feeling pretty stupid, but I cannot find the other end of the wires. Like 31 I lose it in the bundle then it seems to disappear. Need to walk away. Lol
Quoted from Bax1:lol don't get discouraged, it is easy to lose where they go in the bundle. so good thing is the colored ones go to the diode board. so look for those colors to the diode boards. then from the diode board to A1J6. Hope this directs you to where the wires go.
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Thanks for words of encouragement. So found the wires on the DIODE that matched and they all have continuity. So the loss appears to be from the DIODE board to the MPU (Control Board). Is that correct thinking. If so, the next question is what wire to trace. Is it the 433? Only thing is I know top right Bumper works. This is where I am confused. Thanks again for all your help.
Might want to check those diodes. You will need to unsolder one side to test. That only thing I can think of.
Calling ChrisHibler
Might want to check those diodes. You will need to unsolder one side to test. That only thing I can think of.
Calling chrishiblerNew problem out of nowhere. Start button not working and game won’t start. Test mode shows all switches open and none will register now. I made no modifications today and it was all working except the Three switches this morning. These things sure can drain you.
Quoted from Bax1:Do you have 5v going to the board?
I have a new power supply board. Not sure where to look for diagnostics on the board.
Going to see if these guys might be able to help. They helped me out a ton with mine
Quench
ChrisHibler
you fixed another problem 
been there before lol. so i still think you need to check those diodes. either use a flash light while looking at them or pull one side from the board and then test. they can be tricky to see if they've blown
Quoted from Bax1:you fixed another problem been there before lol. so i still think you need to check those diodes. either use a flash light while looking at them or pull one side from the board and then test. they can be tricky to see if they've blown
Ok I will take a closer look. They are tiny. Thanks
Quoted from Bax1:you fixed another problem been there before lol. so i still think you need to check those diodes. either use a flash light while looking at them or pull one side from the board and then test. they can be tricky to see if they've blown
I took a pic. As a rookie not sure what I’m looking for.
6A007111-F955-4BDF-BCCE-23B046C2019D (resized).jpegOkay guys...brief me up. Too long of a thread to pour over.
—
Chris Hibler - CARGPB #31
Http://chrishiblerpinball.com/contact
http://www.PinWiki.com/ - The new place for pinball repair info
And the other switches on that row do register, right?
Just a comment, physical switch connections will almost never match the order of switches as shown in the schematic. Switch matrix (and other) wiring is routed to minimize wire required.
Some switches in a row working but others in that same row not working rules out the MPU board and the connection to the board, assuming all switches come in at the same connector (i.e. all on PF or in cabinet.
This leaves only a few possibilities in this approximate order of probability.
1. Broken daisy chain between switches. Buzz from switch solder tab to all others in the daisy chain.
2. Failed switch. Clean the gold flashed contacts but pinching a business card between them and pulling it through. Meter for continuity when closed.
3. Failed 1N270 germanium diode or solder joint on the diode board. Remove the connector. Examine solder joints. Diode year with a meter. Should be open one way and about .220 the other way IIRC.
4. Failed IDC connection at diode board.
Multiple switch failures are almost always a break in the daisy chain.
Happy hunting soldier!
—
Chris Hibler - CARGPB #31
Http://chrishiblerpinball.com/contact
http://www.PinWiki.com/ - The new place for pinball repair info
ChrisHibler and
Bax1 I am a first timer trying to restore my first machine. So I apologize I do not know all the lingo. Can you help me out on the following:
1. Buzz from switch solder tab to all others in the daisy chain. - What is this process?
The rest I understood. I am assuming no way to test DIODE by just looking huh?
Also, the daisy chain side of the switch is for the power? Can I attach them to any other switch as long as the oher line is going to the correct circuit/board?
Thanks again for helping me out.
pasted_image (resized).png1. Broken daisy chain between switches. Buzz from switch solder tab to all others in the daisy chain.
Test the continuity between these switches with on the same colored wires. so from 33 to 35, then 35 to etc..
to test the diodes, put your meter on diode test. one way you will get open or the sound from meter. other way you will get the reading that is stated above.
you got this!!!
Quoted from Bax1:Any update muggy?
Still not resolved. Diodes are good, board good. What I thought was the daisy chain changes color somewhere I cannot trace to test. My guess is the schematic May not be totally accurate. Is there a way to power the switches for a test ? So close to getting this thing finished.
Have an awesome weekend
Quoted from Bax1:so you have the button on the left inside the coin door to get into test mode. you keep hitting it till you get to switch test. it will then run through all the switches that are registering closed.
Thanks. What I meant, is there another way to get power to these switches? If the continuity is good to the diodes and board, I assume the power is not getting to the switches somehow. That is the Daisy chain? Just trying to find ways to get this to work.
Quoted from Bax1:the daisy chain is the ground. each switch should have a separate color for power. (I think) you could test the switch continuity. have a probe on each end of the tab and then activate the switch to see if it has continuity.
So the power goes from diode to switch? Or is it the other way around? I don't get the row concept. I thought they all were powered together. So just grounded together?
--
Chris Hibler - CARGPB #31
http://www.ChrisHiblerPinball.com/Contact ... for board repairs
http://www.PinWiki.com - The Place to go for Pinball Repair Info
Quoted from ChrisHibler:--
Chris Hibler - CARGPB #31
http://www.ChrisHiblerPinball.com/Contact ... for board repairs
http://www.PinWiki.com - The Place to go for Pinball Repair Info
Thanks!
Quoted from Bax1:how are you coming along on this muggy?
So I have a fully functional Monte Carlo now! Two Diodes were bad. However, the problem was found to be the left drop bank was shorting out the switches. This caused one of my switch matrix chips to blow on my new board. However, it is good to go now. My guess is the wiring issues I spoke of before from the previous owner did this. But it is fixed now. Took me a while but thanks to you guys for all your help! Moving it downstairs to the game room tonight! Did you get yours fixed?
Now play the crap out of it!!!Quoted from Bax1:Awesome!!! good job!!!! Now play the crap out of it!!!
yeah mine is good now. I had a broken trace, fixed but then went wonky again. I still may buy your old boards.
Oh no! Hopefully it will get repaired easily for you. I actually traded my boards for some repair help from a local tech I found. Sorry. And yes, we have a family tournament planned for tonight! I also think I convinced my wife to get another project pin 
I want one I played in college all the time: The Simpsons
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