Repair Miss O center target issues

MissO-owner

Pinball Nudger
I have an issue with the center target on my Miss O machine, The center target is relatively simple circuit which makes this more frustrating. What is happening: when the center target light is lit and you hit the target, the pool ball lights do not advance. When the center target is hit, it looks like there is a short at the target switch (a big spark), in fact if any of the ABCD lights on lit, they go out. I do get the 10 points for hitting the relay, the change relay switch is closed at this time and the target relay did not energize. If I put a piece of cardboard between the change relay switch (between the Grey-R and Grey-G switch), I don't get a short (ABCD lights stay on), but the target relay still does not energize, hence the pool ball does not advance, however I still get the 10 points. I think, somehow the 3/5 ball adj. comes into play, when I disconnect it, (leave it out), then hitting the center target will: no short, energize the target relay and advance the pool ball. To be clear the center light is not lit at this time, however the light on the left eject hole is lit. Any thoughts?
 
Solution
I tracked that Gray-G wire to the jones plug in the back cabinet and guess what, I found a washer stuck in the back of the plug (I wondered where that went?). Took the washer out, and checked to make sure I wasn't getting continuity on that wire. Soldered all the wires back and everything seems to play as it should. Again thanks for your help.
Congrats on your repair
My guess would be that it was the jones plug under the step units.
Check if the washer slips over any of the step unit black pivot posts.
Pinball database has a inside backbox pic if needed for comparison or post pics of units yourself.

MissO-owner

Pinball Nudger
Hi, so I cleaned all the jones plugs, made sure they were installed correctly, and checked for any loose or shorted wires (none). Also check the change relay for any loose wires or shorts (none). But no luck. When I have that piece of cardboard between the change relay switch (between the Grey-R and Grey-G switch), everything seems to work, except when the center target light is lit and you hit it, the target relay still does not energize, hence the pool ball lights do not advance, however I still get the 10 points. Also when I manually engage the target switch (with or without the cardboard) and if the ABCD lights are lit, there is a short and they go out (sometimes 1, 2 or all of them and sometimes blows the 15 amp fuse). Without the cardboard, and when the ABCD lights are lit, and if you hit the center target (when the center target light is lit) that shorts out the ABCD lights, and if I manually engage the target relay, same shorting occurs. This is starting to drive me over the brink, I'm almost to the point where I'll just make sure that change relay switch (switch A) is never engaged and just live with the fact the center target won't advance the pool ball lights. The pool lights advance for the top and center rollovers and the left and light eject holes (when lit). Just not the center target, when lit.
 

pinballdaveh

Pinball Technician
Staff member
Site Supporters
Hi, so I cleaned all the jones plugs, made sure they were installed correctly, and checked for any loose or shorted wires (none). Also check the change relay for any loose wires or shorts (none). But no luck. When I have that piece of cardboard between the change relay switch (between the Grey-R and Grey-G switch), everything seems to work, except when the center target light is lit and you hit it, the target relay still does not energize, hence the pool ball lights do not advance, however I still get the 10 points. Also when I manually engage the target switch (with or without the cardboard) and if the ABCD lights are lit, there is a short and they go out (sometimes 1, 2 or all of them and sometimes blows the 15 amp fuse). Without the cardboard, and when the ABCD lights are lit, and if you hit the center target (when the center target light is lit) that shorts out the ABCD lights, and if I manually engage the target relay, same shorting occurs. This is starting to drive me over the brink, I'm almost to the point where I'll just make sure that change relay switch (switch A) is never engaged and just live with the fact the center target won't advance the pool ball lights. The pool lights advance for the top and center rollovers and the left and light eject holes (when lit). Just not the center target, when lit.
I think manually engaging the target relay and the problem shows is a clue.
When you manually engage the relay, a switch will close to power the advance unit step up coil.
Another switch on the relay is for it’s hold in circuit. When closed power is sent to the advance unit end of stroke normally closed switch.
On some step units the frame of the unit will be powered to be used as a common for certain wiper blade fingers, often lights.
This means that all metal on the unit is powered including the end of stroke actuating rod.
If the end of stroke switch is missing it’s insulating fish paper, when the advance coil pulls in the short will happen.
Try to insulate the actuating rod with some tape and retest.
 

MissO-owner

Pinball Nudger
Hi, here's a picture of the advance unit EOS, the fish paper looks OK, however I did put on some tape and no luck. I think the EOS is OK since the fact that the advance unit works as it should for the top and center rollovers and the left and light eject holes (when lit). Another guy suggested that I check the resistance on the target coil, since that might be bad. I did and it was only .8 ohms and it should be around 16 ohms. So I ordered a new coil and we'll see. Thanks for your help.
 

Attachments

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MissO-owner

Pinball Nudger
Well, now I'm not sure its the coil, when I measured the resistance of the target relay coil when it was still wired in, I got the .8 reading. However, when I unsoldered the wires and then measured the resistance of the coil, I got 17.3, which I think means the coil is OK ?
Since I had the multimeter out, I took some more readings:

1. When the 3/5 adj. was in the 5 ball side, from the Gray-R connection on the center target switch to the Gray-R connection on the change relay "A" switch, there was no continuity? I would have thought there would be a connection. However when I plug the 3/5 adj. in the 3 ball side, I got 18.3 ohms, which is probably a problem?

2. From the center target Gray-R connection to the Gray-G connection on the target relay coil, I get 17.9 ohms, in both the 3 or 5 ball option.

What does all that mean?
 

pinballdaveh

Pinball Technician
Staff member
Site Supporters
Well, now I'm not sure its the coil, when I measured the resistance of the target relay coil when it was still wired in, I got the .8 reading. However, when I unsoldered the wires and then measured the resistance of the coil, I got 17.3, which I think means the coil is OK ?
Since I had the multimeter out, I took some more readings:

1. When the 3/5 adj. was in the 5 ball side, from the Gray-R connection on the center target switch to the Gray-R connection on the change relay "A" switch, there was no continuity? I would have thought there would be a connection. However when I plug the 3/5 adj. in the 3 ball side, I got 18.3 ohms, which is probably a problem?

2. From the center target Gray-R connection to the Gray-G connection on the target relay coil, I get 17.9 ohms, in both the 3 or 5 ball option.

What does all that mean?
Can you post a pic of the underside of the playfield, focusing on the target switch and it’s connections.
 

MissO-owner

Pinball Nudger
As requested here are pics of the target switch, target relay (need to reconnect), change relay and bottom of the playfield. Let me know if you need more or better pics. Thanks.
 

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pinballdaveh

Pinball Technician
Staff member
Site Supporters
As requested here are pics of the target switch, target relay (need to reconnect), change relay and bottom of the playfield. Let me know if you need more or better pics. Thanks.
In the pic of the target relay, it looks like the coil isn’t positioned correctly, it may be loose.
If any coil connector is touching the relay frame, a possible short can happen if the relay frame might be touching or powered by another wire.
So checking coils for being straight and tight is important.
 

MissO-owner

Pinball Nudger
Yea, I had taken the target coil out when I thought that it was the problem and I just haven't put back to together yet since I did order a new coil. I soldered in the new coil today, and same issue (short at the target switch when the center target light is on, and in the 5 ball mode) . What I don't understand is when the coil is not wired in and I test the resistance I get 16.8, but wired in, I get .8 and when I take the 3/5 adj plug out I get 16.8. And BTW, with the 3/5 plug out, the target switch works as it should, advancing the the pool ball light without any short. So I'm thinking it must be something with that 3/5 adj plug? I never touched it and it looks OK to me?
 

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pinballdaveh

Pinball Technician
Staff member
Site Supporters
Yea, I had taken the target coil out when I thought that it was the problem and I just haven't put back to together yet since I did order a new coil. I soldered in the new coil today, and same issue (short at the target switch when the center target light is on, and in the 5 ball mode) . What I don't understand is when the coil is not wired in and I test the resistance I get 16.8, but wired in, I get .8 and when I take the 3/5 adj plug out I get 16.8. And BTW, with the 3/5 plug out, the target switch works as it should, advancing the the pool ball light without any short. So I'm thinking it must be something with that 3/5 adj plug? I never touched it and it looks OK to me?
I agree
The 3/5 ball adjustment is suspect.
Can you post pics of the adjustment in 3,5 and not inserted modes.
 

MissO-owner

Pinball Nudger
Hi, attached are the pics of the 3/5 adjustment inserted/not inserted and I took a picture of the bottom. I don't see any loose or missing wires, or any evidence of a short. Also to be clear, with the 3/5 plug in either the 3 or 5 ball option, I get a reading of .8 on the target coil, but not inserted, I get 16.8. And I did the same ohm test on the change relay coil, and I get 1 ohm when the 3/5 plug is inserted (3 or 5 ball) or not. But when I unsoldered the wires, I get 14.8, which I think means it is OK.
 

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pinballdaveh

Pinball Technician
Staff member
Site Supporters
Hi, attached are the pics of the 3/5 adjustment inserted/not inserted and I took a picture of the bottom. I don't see any loose or missing wires, or any evidence of a short. Also to be clear, with the 3/5 plug in either the 3 or 5 ball option, I get a reading of .8 on the target coil, but not inserted, I get 16.8. And I did the same ohm test on the change relay coil, and I get 1 ohm when the 3/5 plug is inserted (3 or 5 ball) or not. But when I unsoldered the wires, I get 14.8, which I think means it is OK.
Unsolder the gray-r wire from the center target switch and redo your resistance test on the target relay coil just like your last post.
Post results.
 

MissO-owner

Pinball Nudger
With the 3/5 plug in the 5 point option or in the 3 ball option:
1. Between the leads on the target coil, I still get .8 ohms.
2. Between the Gray-R wire on the target coil that does the 10 point advance to the Gray-G on the target coil or to the Gray-G on the change relay switch, I get 17.3 ohms
3. Between the other Gray-R wire on the target (I assume that is the one that is suppose to energize target coil?) and the to target or change coils I don't get any continuity.

With the 3/5 plug out:
1 15.8 ohms on the leads to the coil.
2. 17.3 ohms from the 10 point wire and 32.5 (seemed high) ohms to the Gray-G wire on the change relay
3. Still no continuity from the other Gray-R wire

Here's the other thing that seemed strange to me, with the two red wires off the center target switch and the center light on (the change relay engaged), when you hit the center target switch, I get the short. I had to do it a few times to make sure what I was seeing. What could that mean? Center target looks OK to me
 

pinballdaveh

Pinball Technician
Staff member
Site Supporters
With the 3/5 plug in the 5 point option or in the 3 ball option:
1. Between the leads on the target coil, I still get .8 ohms.
2. Between the Gray-R wire on the target coil that does the 10 point advance to the Gray-G on the target coil or to the Gray-G on the change relay switch, I get 17.3 ohms
3. Between the other Gray-R wire on the target (I assume that is the one that is suppose to energize target coil?) and the to target or change coils I don't get any continuity.

With the 3/5 plug out:
1 15.8 ohms on the leads to the coil.
2. 17.3 ohms from the 10 point wire and 32.5 (seemed high) ohms to the Gray-G wire on the change relay
3. Still no continuity from the other Gray-R wire

Here's the other thing that seemed strange to me, with the two red wires off the center target switch and the center light on (the change relay engaged), when you hit the center target switch, I get the short. I had to do it a few times to make sure what I was seeing. What could that mean? Center target looks OK to me
Thank you for the updated info.
With the target relay wires unsoldered from the switch, and the switch closed, 10 points should score. Instead the short shows up.
The 10 point relay drives 10s score reel and the large bell. If the large bell coil is almost shorted it will try draw as much available amps as it can causing other already pulled in coils to drop out and not allowing other coils like target relay or advance unit step up coil to pull in.
Large bell and knocker might be wired together on one jack. Unplug large bell jack.
Test for proper operation of machine.
Test and report resistance of large bell coil.
 

MissO-owner

Pinball Nudger
I unplugged the large bell and knocker plug, they are both on the same 4 point jack (see attached pic) and got the same results, when the center target light is lit, and when the center target is closed, I still get a short (both center target wires are still unsoldered). To be clear, when the center target light is not lit, I don't get the short. I also tested the resistance on the large bell and knocker coils (both are A2-23-750) and got 3.9 for both.

Also both the large bell and knocker work as they should, except I assume the knocker should go off when all 15 balls are lit and the right and left bottom are lit for "Special", and if the ball rolls down I should get a replay, which I don't. The knocker does goes off on a replay for the max score and number match and I do get a replay for both. I'll worry about this issue later.
 

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pinballdaveh

Pinball Technician
Staff member
Site Supporters
I unplugged the large bell and knocker plug, they are both on the same 4 point jack (see attached pic) and got the same results, when the center target light is lit, and when the center target is closed, I still get a short (both center target wires are still unsoldered). To be clear, when the center target light is not lit, I don't get the short. I also tested the resistance on the large bell and knocker coils (both are A2-23-750) and got 3.9 for both.

Also both the large bell and knocker work as they should, except I assume the knocker should go off when all 15 balls are lit and the right and left bottom are lit for "Special", and if the ball rolls down I should get a replay, which I don't. The knocker does goes off on a replay for the max score and number match and I do get a replay for both. I'll worry about this issue later.
The 2 gray- r wires unsoldered from the center target switch, unsolder them apart, tape each end and set aside.
The 2 gray-r wires connected to the change relay switch, unsolder from switch, unsolder them apart, tape each end and set aside.
do the same for the gray-g wires on the change relay.
Unsolder the gray-g wire from the target relay, tape and set aside.
Run a alligator jumper from the center target switch lug to one of the change relay switch lugs.
Connect another jumper from the other switch lug on the change relay to the lug on the target relay switch where the gray-g came off of.
Retest machine.
Individual unsoldered wires can now be tested for continuity, and shorts to either yellow or black wires.
 

MissO-owner

Pinball Nudger
Hi, first I want to thank you for sticking with me on this issue. Being a newbie, I'm still learning.

I did all the unsoldering and hooked up the jumpers as you stated. The good news is now when the center target light is lite and you hit the center target, I don't get the short (the ABCD lights stay lit) and it advances the pool ball light, just as it should. However, I noticed that now when the center target is lite and you hit one of the ABCD targets that also advances the pool ball light, which is not suppose to happen.

I also tested the unsoldered wires between the yellow wire on the center target switch for continuity or shorts, for most I get no continuity except for the following
1. For the Gray-R wire on the center (that rings the bell for 10 points), I get 17.5
2. For one of the Gray-G wires on the Change Relay, I get .9

So I think we're making progress.
 

pinballdaveh

Pinball Technician
Staff member
Site Supporters
Hi, first I want to thank you for sticking with me on this issue. Being a newbie, I'm still learning.

I did all the unsoldering and hooked up the jumpers as you stated. The good news is now when the center target light is lite and you hit the center target, I don't get the short (the ABCD lights stay lit) and it advances the pool ball light, just as it should. However, I noticed that now when the center target is lite and you hit one of the ABCD targets that also advances the pool ball light, which is not suppose to happen.

I also tested the unsoldered wires between the yellow wire on the center target switch for continuity or shorts, for most I get no continuity except for the following
1. For the Gray-R wire on the center (that rings the bell for 10 points), I get 17.5
2. For one of the Gray-G wires on the Change Relay, I get .9

So I think we're making progress.
The ABCD targets probably use the same 3 wire 3 blade switch and need to be checked. Removing plastics makes switch cleaning and checking easier.
Does a relay pull in when this happens?
 

MissO-owner

Pinball Nudger
Hi, I should have mentioned that I had one of the Gray-R wires (the one that does the 10 point and bell) connected to the center target switch.

So to recap, with all the unsoldered wires and jumpers in place:

With the Gray-R wire attached to the center target switch:
1. When the center target light is not lit (change relay not energized), everything works correctly, when hit you get 10 points and the large bell rings.
2. When the center target light is lit (change relay is energized), when you hit the target you get 10 points, the large bell rings and the pool ball light advances. All good, except as I mentioned if you hit one of the ABCD targets the pool ball advances (maybe that is how the game works?)

With that Gray-R wire unattached:
1. Center light not lit, nothing happens (no 10 points or bell)
2. Center light lit, no 10 points, no bell, but the pool light does advance (target relay energizes). However now when you hit one of the ABCD targets, the pool light does not advance.

Also I noticed today and I don't know if this is related, when the "D" target is hit and lit, that also lights the bottom jet bumper for 10 point scoring, however I don't get 10 points and the large bell doesn't ring. When the "D" target is not lit, I do get the 1 point and the small bell rings.
 

pinballdaveh

Pinball Technician
Staff member
Site Supporters
Hi, I should have mentioned that I had one of the Gray-R wires (the one that does the 10 point and bell) connected to the center target switch.

So to recap, with all the unsoldered wires and jumpers in place:

With the Gray-R wire attached to the center target switch:
1. When the center target light is not lit (change relay not energized), everything works correctly, when hit you get 10 points and the large bell rings.
2. When the center target light is lit (change relay is energized), when you hit the target you get 10 points, the large bell rings and the pool ball light advances. All good, except as I mentioned if you hit one of the ABCD targets the pool ball advances (maybe that is how the game works?)

With that Gray-R wire unattached:
1. Center light not lit, nothing happens (no 10 points or bell)
2. Center light lit, no 10 points, no bell, but the pool light does advance (target relay energizes). However now when you hit one of the ABCD targets, the pool light does not advance.

Also I noticed today and I don't know if this is related, when the "D" target is hit and lit, that also lights the bottom jet bumper for 10 point scoring, however I don't get 10 points and the large bell doesn't ring. When the "D" target is not lit, I do get the 1 point and the small bell rings.
The W-R wires should be for the ten point scoring attached to the center target switch.
the schematic shows the bottom jet bumper comes on with D.
In a previous post a Gray-G wire measured.9 ohms. Tracking this wire thru the harness from point A to point B, should reveal the short.
If the wire goes thru a jones plug, matching wire colors from male to female is important.
the pinball database has both the schematic and the manual to download if you don’t have them already.
The manual will have every relay listed with wire colors connected to each switch and in what circuit each switch operates.
 

MissO-owner

Pinball Nudger
I tracked that Gray-G wire to the jones plug in the back cabinet and guess what, I found a washer stuck in the back of the plug (I wondered where that went?). Took the washer out, and checked to make sure I wasn't getting continuity on that wire. Soldered all the wires back and everything seems to play as it should. Again thanks for your help.
 

pinballdaveh

Pinball Technician
Staff member
Site Supporters
I tracked that Gray-G wire to the jones plug in the back cabinet and guess what, I found a washer stuck in the back of the plug (I wondered where that went?). Took the washer out, and checked to make sure I wasn't getting continuity on that wire. Soldered all the wires back and everything seems to play as it should. Again thanks for your help.
Congrats on your repair
My guess would be that it was the jones plug under the step units.
Check if the washer slips over any of the step unit black pivot posts.
Pinball database has a inside backbox pic if needed for comparison or post pics of units yourself.
 
Solution

Ike Savage

Froggy like robot
Staff member
Site Supporters
I love reading these threads, and congratulations to you two for drilling down so far until the gopher was finally located! (heh, or something like that)

Man, I wish I still owned some EM's at times like these. :s
 
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