Have an interesting diagnosis that you want to share? Want to bone up on your diagnosing skills? If so, then this is the thread for you.

Post all pertinent information and clues that are needed to solve the puzzle, but DON'T provide the answer. DO please let a respondent know if he or she has the right answer. You can provide more clues if answers are not forthcoming. If no one gets the answer, please DO provide it so we can all learn from your experience!

DO please link your game to this topic so others may find it more easily.

Please DO NOT post specific EM problems that you may have here.

Please DO quote the original question in your post so others will know which question you are answering.

If you are trying to figure out the solution, you may ask questions, but the OP may or may not answer your question - DON'T want to make it too easy!

I know quite a bit about EMs, but I certainly don't know it all. If I get something wrong or you want to clarify a murky answer, please chime in!

I know Williams and Bally pins from the 70s the most and those will be the machines I use as examples. Gottliebs are different and since I know squat about Gottlieb pins, please help me out if you find an answer that is appropriate for Williams/Bally but incorrect for Gottieb.

Here is a fairly easy one, but with a twist!

Problem: A 1976 Williams EM Grand Prix was not advancing the ball count. The player could play ball one over and over. If you tilted the game, the ball count would advance when the ball reached the outhole. If the ball went up the left lane to the top, the game would tilt and ball count would advance when the ball reached the outhole. Where do you look first when trying to fix this problem?

I'll give you a 'You are correct sir' for your answer.*

In short, I'd first look to see if the Ball Index Relay was energized or not after the ball was put into play and points scored.

In this case, the Ball Index Relay was NOT energized! Bingo!

You get this exact behaviour if the Ball Index Relay is not energized when the pinball reaches the Outhole.

But why wasn't the Ball Index Relay energized when the pinball was put into play?

The Ball Index Relay energizes when the game is tilted or when points are scored. If you look at the schematic for Grand Prix, as I did, you will find that ANY points, 10, 100, 1,000 or 10,000 points, will energize the Ball Index Relay. When I tested switches on the playfield that scored each one of these types of points, I found that the Ball Index remained NOT energized! I had to look elsewhere for the problem as it was extremely unlikely that switches on all four point relays, found in the backbox, were mis-adjusted.

The twist on Grand Prix is that it is one of only three games, Grand Prix, Liberty Bell and Hot Tip, that have a rollover switch in the left return lane that, when closed before any points are scored, will tilt the game. This is called a Tilt Rollover

It is interesting to note, for some of us EM nerds, that not all games work alike. OXO, for example, will energize the Ball Index Relay ONLY when 1,000 points is scored. This is because the pinball MUST come through a top rollover switch that scores 1,000 points. Unlike Grand Prix, the 10 and 100 point relays will NOT energize the Ball Index Relay.

* The manual shows switch E as normally closed (the Ball Index Relay was not energized), so @cheddar's answer is correct.

Problem: The player one 1,000 point score reel on a 1973 Williams OXO is stuck on '0'. You can hear the solenoid buzzing. You turn off the machine so you won't fry the solenoid to a crispy critter. You take off the backbox door and lift up the playfield to look for what might be the problem. List in order of most likely to least likely all of the reasons why this 1,000 point score reel solenoid is 'stuck on'. Bonus points for suggesting ways to narrow down the culprit.

Great! That is the idea of the thread. As a professor you will know that the teacher often learns more than the students. So, I'm right there with you Ryan!

You are correct sir! This is the first place I would look on the playfield, but with a caveat that I will describe later.

That's a very good answer if you don't know the answer! A schematic is an excellent place to go looking for 'where might the problem be.' You should start by finding the stuck-on solenoid on the schematic, and then following the circuit back to look for what might be causing the solenoid to lock on.

I don't know what you mean by 'arching.' If you mean that the two lugs on the 1,000 point score reel solenoid were touching, then wouldn't that cause a short and blow a fuse when the 1,000 point relay was energized? But I'm not gonna test that theory out!

Actually, it would. At least that is how OXO behaves. Other pins might work as you say. The stuck switch on the playfield would energize the 1,000 point relay and it would stay energized as long as the playfield switch remained closed. The 1,000 point relay would close the switch that energizes the 1,000 point solenoid and it, too, would stay energized until either the playfield switch is opened or that relay switch is opened. The energized 1,000 point solenoid would pull the plunger in but the score reel would not move from zero to one until the solenoid was de-energized and the plunger released.

Ding, ding, ding, ding! We have a winner!

The 1,000 point relay is actually the first place I would look. Why? If the 1,000 point relay coil is stuck-on, then I know that it is a playfield problem and I would then follow Ryan's advice and look at all 1,000 point switches on the playfield. If it wasn't stuck-on, then I would look for the switch on the 1,000 point relay that energized the 1,000 point score reel solenoid. According to the OXO manual, a very handy reference, the switch that "Pulses 1,000 point drum units, thru player unit disc" is switch 1C. If that switch is closed, the 1,000 point score reel solenoid will stay energized and we don't want that! If that switch is adjusted properly, then I have to look elsewhere for the offender.

There is one more, less well known reason left, gang!

So, ladies and gents, for those of you keeping score, so far we have:

1.

OXO 1,000 Point Relay (resized).png

2:

OXO 1,000 Points (resized).png

Lamps, Lamps, Lamps! There are always a few #44 or #47 bayonet lamps that are always flickering, dim or just not working at all. Unless the lamp is burned out, it's usually the lamp socket that it the problem. A lamp socket looks so simple! But it's only been in the last few months that I have been able to turn one of these old lamp sockets into a reliable performer.

Problem: A lamp is flickering on a 1975 Bally Wizard! playfield. Another appears to be dead, even after testing the lamp and finding it to be good. Yet another goes from dim to off. What are the points of failure on a lamp socket and how do you remedy them?

Wizard lamp socket bottom (resized).png

Wizard lamp socket top (resized).png

A hint:

Lamp Failure Points 1-3 (resized).png

Lamp Failure Points 3-4 (resized).png

The six failure points on a typical EM pinball lamp socket - To filament in blue and from filament in red

And, under the hood, a spring!

Lamp Socket Spring (resized).png

As I was thinking about the points of failure on a lamp and lamp socket, I realized that I didn't know the name of all of the parts. I went looking for them and found a few, but not all of them. So, please help me and the pinball world out and name the 'proper' parts of a #44/#47 lamp and 'bayonet' lamp socket.

Oh, one point of note. The pinball world is full of parts with different names. Pop bumpers have been called Jet Bumpers, Thumper Bumpers and, of course, Pop Bumpers. 'Thumper Bumpers' is a cute name but for some reason every time I hear it I think of rabbits and not bumpers that go thump. All of this to say that there may be more than one answer for any part name! So, don't be shy to name these parts. There are lots of 'correct' answers, and we can determine later which part names we deem to be 'proper.'

Name these parts! (resized).png

Lamp Socket Bottom Parts (resized).png

The correct answers so far:

1.

OXO 1,000 Point Relay (resized).png

2.

OXO 1,000 Point Rollover Switch (resized).png

And now for those of you eagerly awaiting the third common cause:

3. If the normally closed Score Reel Unit Solenoid End of Stroke Switch (SRUSEOSS), let's call it EOS switch for short, does not open when the solenoid is energized, the solenoid will stay energized and 'stuck-on!' Not a good thing at all. Stop and turn off OXO!

Stepper Unit EOS Switch (resized).png

Please note that on Williams and Bally pins in the 70s, the far leftmost score reel does not have this EOS switch.

Look ma! No SRUSEOSS (Score Reel Unit Solenoid End of Stroke Switch)!

DSCF4272 (resized).JPG

Question: Why does the leftmost score reel unit on OXO, and other pins from this era, not have an EOS switch like the other score reels?

The leftmost score reel can be:

• The 100,000 score reel on a game that goes to 999,999
• The 10,000 score reel on a game that goes to 99,999
• The 1,000 score reel on a game that goes to 9,999

Excellent, if by 'precious digit' you mean what I think you mean! OXO has no 10,000 point relay. The only way the 10,000 score reel can advance is when the 1,000 point score reel goes from 9 to 0. The 1,000 point relay and a switch on the 1,000 point score reel handles the energizing/de-energizing of the 10,000 point score reel solenoid.

Beautiful diagram Rolf and Welcome! Thanks for posting it. I want you to know how sad I was when I heard of your medical issues. I am heartened to see you back in the game and posting again.

We seem to have, independently, come up with similar solutions.

All good answers. I forgot about a weak spring and not securely holding the lamp answers so you get extra bonus points!

This is an alternate solution that I don't like, but may be perfect for you. There is almost always more than one way to fix a problem and if you like the solder method, gopher it!

I forgot about the solution of last resort, replace the lamp socket! I have done this more than once. Bonus points for a solution that I had forgotten about.

Cleaning the lamp and lamp socket is the solution for oxidized metal. Perhaps you have seen this oxidation. It is a white coating on the lamp socket and is the enemy of proper electrical connections. There can also be corrosion and dirt, your basic 'grunge', on the connection points.

I use 91% Isopropyl alcohol and @nicovolta's Magic Brush. The Magic Brush is a Dremel tool and a #443 wire brush and it is the best method I have found for cleaning corroded and oxidized EM parts.

DSCF4263 (resized).JPG

First, use a Q-Tip soaked in Isopropyl alcohol to clean. Then use the Magic brush to polish. Then, again use a Q-Tip and Isopropyl alcohol but drier this time. I am going to call this the IPI cleaning method, Isopropyl, Polish and Isopropyl.

Lamp Socket Points of Failure Bottom (resized).png

Lamp Socket Failure Points Top (resized).png

Connection points 2, 3, 4 and 5 get the IPI treatment. Point 2 is best cleaned by pushing down on the lamp socket 'center post,' (still need the name of these parts), just as Rolf shows.

I used a little bit of solder wire, tightly tied, as a last resort if the connection was still bad, but a good polishing should give you a good electrical connection. If you must use a wire, Rolf's copper wire is a much better solution than solder wire. Solder wire melts too easily and is too 'fat!' Like you Rolf, I do NOT like using solder on my lamp sockets.

I was working on a Capt. Fantastic and The Brown Dirt Cowboy when I discovered that the lamp contacts were badly oxidized, a good reason why most of these bonus lamps weren't lighting. I usually just replace all lamps with new lamps, so I had not seen this problem before. A quick polishing of connection points 3 solved the problem.

The Harlem Globetrotters On Tour I was restoring had a 'dead' lamp on the GI lamps. After a lot of consternation, I discovered that the 'from transformer - hot?' 6 Volt wires had been soldered to BOTH points 1 and 6! Electricity will not flow through that type of connection!

Here is a summary of how to fix the six failure points on a lamp and lamp socket:

Connection Point 1: Look for loose wires. Check to make sure there is a solid solder joint. Verify that the 'from transformer' 6 Volt AC wire is connected and NOT the 'to transformer - neutral?' usually bare wire. Please, someone, correct me if I have those wire names wrong.

Connection Points 2, 3, 4 and 5: Gets the Q-Tip soaked in Isopropyl alcohol, Magic Brush to polish and Q-Tip and Isopropyl alcohol, (IPI), treatment. Be sure to thoroughly clean and polish connection points 4 where the bayonet nubs attach to the socket! This point of electrical connection is often overlooked but just as important as the other connection points.

Lamp Socket Oxidation (resized).png

Filthy exploded lamp socket parts.jpg

Just look at all of the corrosion and oxidation on these lamp socket parts! After you are done with IPI cleaning, these parts should be gleaming!

Connection Point 6: Similar to Connection Point 1. Look for loose wires. Check to make sure there is a solid solder joint. Verify that the 'to transformer - neutral?' 6 Volt AC usually bare wire is connected and NOT the 'from transformer - hot?' wire.

A lamp in a lamp socket looks like such a simple bit of pinball engineering. But, I hope that you now realize how complex it really is and how to best get those EM incandescent lamps of yours shining brightly, once again.

When I bring a 'new' Project Pin into Pecos' Palatial Pinball Parlour, it is almost a certainty that at least one of the score reels will not be working properly. On OXO, there are three switches on each of the 10 Point, 100 Point and !000 Point Score Reel Units. The 10,000 Point Score Reel Unit has only two. It's good to know how these switches work and what they do when trying to debug Score Reel issues.

Question #1: Why does the 10,000 Point Score Reel Unit have only two switches?

Let's go back to our, now infamous, OXO 1000 Point Score Reel Unit.

In these pictures you can see these three switches. These switches can be in one of three states:

State 1:
Top switch Open.
Middle switch Open
Bottom switch Open

Score Reel Switches OOO (resized).jpg

State 2:
Top switch Closed
Middle switch Closed
Bottom switch Open

Score Reel Switches CCO (resized).jpg

State 3:
Top switch Closed
Middle switch Closed
Bottom switch Closed

Score Reel Switches CCC (resized).jpg

Question #2: What number(s) will you see on the Score Reel when the switches are in State 1?
Question #3: What number(s) will you see on the Score Reel when the switches are in State 2?
Question #4: What number(s) will you see on the Score Reel when the switches are in State 3?

It's time to tally up the points! Oh goody!

Generally speaking, a correct answer will earn you 100 points. Answers to easy question earn 50 points. Bonus points are either 25 or 50 points, depending on the quality of the answer and the complexity of the issue.

Special points will be awarded for special posts, like 250 points for @rolf_martin_062's informative diagram and for a tip to help fix lamp socket issues.

Asking a question earns you 50 points. Answering/grading your own question earns you 100 points, but please give Pinsiders a few days to answer before you do.

I reserve the right to modify the rules of this 'just for fun' point system.

Pecos is disqualified from earning points!

rolf_martin_062 - 250 Points
RocketFromTombs - 200 Points
RyanClaytor - 175 Points
zacaj - 150 Points
Stoomer - 150 Points
Cheddar - 150 Points
bingopodcast - 150 Points
Colsond3 - 100 Points

We are working our way through Score Reels, how they work and what their parts do.

Three of the four OXO's Score Reels for player one have PCBs (Printed Circuit Boards). One does not.

DSCF4284 (resized).JPG

Example of PCB on OXO's Score Reel (resized).png

Again with the infamous OXO 1000 Point Score Reel! An example of the PCB

Question 1: The 10's Score Reel does have a PCB. Why is it there / what does it do?
Question 2: The 100's Score Reel does NOT have a PCB. Why not?
Question 3: The 1000's Score Reel does have a PCB. Why is it there / what does it do?
Question 4: The 10,000's Score Reel does have a PCB. Why is it there / what does it do?

Winner! Winner! Chicken Dinner!

And the reason the 10,000 Point Score Reel Unit does not have a 9th position carry over switch is because OXO has no 100,000 Point Score Reel.

@pinballdaveh, you have earned 200 points for your answers!

Wow! Very and informative and thorough answer. This earns you 100 points for the answer and 50 special points for thoroughness.

Your answer awards you 50 points for the answer and 50 special points for (trying to) answer your own question.

This is exactly how it should be done - let the person answering the question know that there is more to the answer. For such an excellent reply you earn 200 points!

Perfect answer! 100% correct. You earn 100 points

100 more points! I am glad that you guys answered the No. Match Unit question, or the Mini-Match as I like to call it. I have spent more than two days trying to fix one of these PITA units on an Aztec and I never did get it working. I would have written a long rant about how much I hate these things and how I tried to fix it and how I spent three more days restoring the backbox on another Aztec only because it had a working Mini-Match unit! I better stop now. I'm headed to that small dark place...

Good to see that someone who knows Gottliebs is asking Gottlieb questions! I know very little to nothing about Gottlieb pinballs.

You earn 100 points for the question and another 50 special points for helping me out with Gottlieb Q's and A's.

75 points for the answers and 25 bonus points for answers that you aren't 100% sure of.

Another good reply to the answerer! 150 Points awarded!
P.S. I'm pretty sure that I made that word up.

I'm not always going to be detailing how I award points. I wanted you to see the strange and bizarre thought processes that go through my abused brain when trying to best award points.

Absolutely correct sir! To your total, 200 points will be added.

It is interesting that you should note the additional combinations by using the 1000 Point Score Reel. I haves seen games with PCBs on only the 10's and 10,000 Score Reels. I think it was a 70s Williams single player.

It's time to tally up the points again! Oh goody goody gumdrops!

pinballdaveh - 800 Points
bingopodcast - 600 Points
rolf_martin_062 - 250 Points
zacaj - 250 Points
RocketFromTombs - 200 Points
RyanClaytor - 175 Points
Stoomer - 150 Points
Cheddar - 150 Points
Flamingo43 - 100 Points
Colsond3 - 100 Points