1973 Gottlieb Pro-Football: Startup Glitchiness

Could you post a photo of the startup sequence page form the manual - that would be very helpful!

Gottlieb Pro Football
OPERATING INSTRUCTIONS
1. Inserting a coin actuates "S" relay (Start Relay).
2. This relay will lock in thru its own switch and a motor 2B switch.
3. The following sequence thru the closed switches on "S" relay.
a. The motor starts running.
b. The total play meter and AB relay coil are actuated by switches on motor 3C and motor 1A.
c. The reset "Ball Count" unit coil is energized returning the unit to zero.
d. The advance unit ("I" relay) is pulsed by motor 1A to its zero position.
When "AB" relay coil is actuated it is locked in by the armature of "AB" reset coil. A switch on "AB" relay closes and actuates "Z" relay. Thru closed switches on "Z" the point score and high score units reset to zero thru switches on motor 1A and motor 4A. When all units are reset to zero and motor 4D makes[*], "AB" reset relay is actuated. This releases the armature on "AB" relay and opens the switch that actuated "Z" relay. The reset cycle is now complete. [* - Note, seems they omitted a word here ... I assume it should be "makes contact"?]
4. Place the ball in the outhole. When the ball closes the ball return switch "Q" relay is actuated, a switch closes and pulls in "P" relay thru normally closed switches on "O" relay and motor 1C. When "P" relay pulls in the motor starts running. The normally open switches on "P" relay close, completing the circuit to "O" relay and the add "ball count" unit coil thru motor 4C switch. "O" relay stays locked in thru its own switch and normally closed switches on "L", "M", and "N" relays. The game is now set up for play.
5. Press the right flipper button and the motor starts running. When motor 2C closes the circuit to the ball return coil, it actuates, and propels the ball onto the playfield. When the ball hits a scoring contact "O" relay drops out and both flipper buttons can now be activated. If the ball does not hit any of the scoring contacts it will return to the outhole and the player will press the flipper button again without a loss of the previous ball.
----------End of Operating Instructions-----------

Thanks for the startup sequence

I'm wondering if the O is relay not locking in because the operating pulse is not long enough. When the P Relay operates it locks in over it own contact and a 2B switch and the motor starts. When the 4C switch closes (BR+BLK and BL+BLK) O relay operates through the P contact. The 2B switch then opens and P releases. On the motor sequence chart 4C and 2B overlap. If 4C is delayed then the pulse operating O may be too short.

Could you post a closeup photo of the Motor 4C switch stack that also shows the cam and operating leaver?

I want to check the position of the S/L follower. It should be in the S position but if it was in L, the pulse to O relay would be shortened (I think!)

What happens if you jumper the motor 4C switch (BR+BLK and BL+BLK)? O relay should lock in as soon as P operates.

Still researching this problem... Looking at the photos of the score motor can you confirm that the switch with the black/yellow wire and the two purple wires, the lugs and/or the solder on those lugs are "not" touching each other?

Still concentrating on the issue of why the ball count stepper continuously counts through all five balls after the start button is pressed...

For the ball count advance solenoid circuit, power comes from the transformer and branches off to the individual circuits. Power arrives at the AB relay and is sent to score motor switch 4C. The score motor runs and opens/closes switch 4C, which sends "pulses" of power to P relay switch. In turn, the P relay switch sends power to the ball count advance solenoid.

There's also a secondary circuit that sends power to the ball count advance solenoid. This circuit sends power to a P relay switch and then to score motor switch 1A, and then to another P relay switch and then to the ball count advance solenoid.

First Circuit
AB relay switch - this is a main "gateway" switch that sends power to various circuits
Score motor switch 4C - sends "pulses" of power to P relay switch
P relay switch - the last switch that sends power to the ball count advance solenoid

Secondary Circuit
P relay switch - sends power to the ball count stepper contacts
Score motor switch 1A - receives power through the ball count stepper contacts
P relay switch - the last switch that sends power to the ball count advance solenoid

So, for the ball count advance solenoid to work properly, it needs a gate that opens/closes to regulate those "pulses" of power. And that's all the ball count advance solenoid needs - just a quick pulse of power to get the ball stepper to "click" to the next ball position. And it seems switch 4C is sending these power pulses properly.

From this concept, I'm thinking the P relay switch is the switch that regulates power to the ball count advance solenoid. Also, score motor switch 1A can pulse power to the ball count advance solenoid. Check the following:

P relay switch - switch with orange/black wire and orange/blue wire
P relay switch - switch with white/brown wire and white/orange wire
Score motor 1A switch - switch with white/orange wire and orange/black wire

As usually, check for shorts, lugs touching, etc... Check these switches first, and then we'll look at the P relay coil circuit...

Also, when you start a game, can you see if the P relay coil is always energized?

When you start a game and it's going through the reset process, can you see if the P relay is always energized? Or during the reset process does the P relay briefly energize and then release? This is with all wires connected to score motor switch 4C.

Might be on the wrong path here, but when you start a game, the ball stepper is working properly. It clicks through all the ball positions. It's just not stopping on ball 1, so the first ball can be played. So, I'm thinking there must be a switch that will cut off power to the ball count advance solenoid when the ball stepper is on ball 1 and when the score motor is running.

Yes, it could be an issue in the ball stepper itself... If you can post a section of the schematic of the ball stepper unit, we can look at that also...

From the photo the follower appears to be in the S position (which is correct)

The O relay should stay locked until a point is scored by the L,M,N relays it should not release after the motor turns with that 4C switch jumpered.

Here's the circuit as I understand it should operate:

Ball return switch closed operates Q.

1. Q stays operated until the ball is kicked out.

2. Q operates P through the normally closed O and Motor 1C switches

3. O operates via relay P and Motor 4C switch. O locks in via its own contact and L,M,N contacts.

4. At the same time relay O is operated, the ADD BALL COUNT UNIT is advanced via P relay and Motor 4C switch.

5. P releases at the end of the motor cycle when the Motor 2B switch opens.

6. Pressing the right flipper starts the motor and the Ball Shooter is activated via the O relay a Motor 2C switch.

7. Scoring any points (L.M,N relays) releases the O relay. If no points are scored and the ball returns to the outhole then pressing the flipper button will shoot ball again without adding another ball count.

Now, if O doesn't lock in then P will re-operate and the sequence continues from point 3 operating the ball count unit until game over. (Which is what appears to be happening to game now).

Here's my latest theory lol:

In a previous post you proved that O does lock in when manually operated and releases when points are scored.

It was proved earlier when you disconnected the Motor 4C (OR+BLK) wire that relay O did lock in. Disconnecting the wire prevented the ball count unit from operating. The ball count shouldn't have any effect on O until it get's to the 6th position when all power is cut from the circuit.

Since the ball count unit operates AT THE SAME TIME as the O relay (both operated by a Motor 4C switch) there is not enough current for the O relay to operate properly. Lets have some pics of that O relay.

Things to check:
What is the coil # for relay O?
Is the relay return spring too tight?
Is there too much tension in the contacts resisting the coil operating?
Is the pole-face of the coil clean?

Actually you might be onto something there - the buzz could be caused by any of the issues I mentioned to check in my previous post.

A loud buzzing coil usually means the coil is working too hard to keep the relay energized... Clay Harrell has a good article about buzzing coils in his pin repair guides:

http://www.pinrepair.com/em/index3.htm#buzz

No teasing intended As mentioned in the article fred referred to, excessive spring tension or switch blades adjusted to give too much spring resistance can cause the buzzing. Too much tension also means the relay may not pull in properly.

From Clay's guide

Hold relays, because they are energized for long periods of time, can be noisy. This buzzing is caused usually by one thing: the spring resistance of the relay is too high. Either the relay spring is too short/tight, or the relay's switch blades are adjusted to provided too much spring resistance. If a relay has to really work to pull in its activator plate, the AC 60 cycle hum will result while the relay is "holding". The AC 60 cycles sets up a vibration which causes the noise. AC means "alternating current", as the voltage goes from 30 volts, to 0 volts, to 30 volts again and again, 60 times a second. As the relay goes to 0 volts, the armature on the relay can release slightly, and then the voltage goes back to 30 volts pulling it back. This often causes the buzz or hum.

Did you buy complete relays or coils? If you just bought coils, I would check that old coil first just to see if it will response to another power source. See if it will work with a 9-volt battery... Replacing the coil might help with the buzzing issue, but not sure how it will affect the start problem you're trying to solve...

Did you check the spring? Maybe try swapping it from another relay...

You may want to just check the solder connection highlighted in the pictures the connection between the Motor 4C BL+BLK wire and the wire that goes to the solder tab of the switchblade that pairs BR+BLK wire (that feeds the O relay).

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If you're doing maintenance on the ball count unit, I would simply just clean the contacts and make sure the switch are adjusted properly. Then try to manually advance the ball count unit to see if it's working properly...

Trying to compare wire colors on different parts of the machine is tough to do. Sometimes the wires are related and sometimes they're not. And sometimes the same wire color is used on different circuits on the machine. Of course, the factory will use different wire colors that aren't noted on the schematic occasionally...

Yep, it's happened to everyone - you make a minor adjustment to some switch or relay and then the machine acts differently. Pretty common.

Remember, if you're doing resistance tests on switches, make sure one of the wires is disconnected from the switch so you'll get an accurate reading on the switch itself...

I think in this situation you should look at one component/circuit at a time. First, we're looking at the ball count advance solenoid circuit. After that we can look at the O relay circuit, P relay circuit, Q relay circuit, etc...

So, we just need to review where we're at now... When you power on the machine, is the machine in game over mode or tilt mode? When you press the start button, do all the score reels reset and is a credit subtracted from the credit unit? Then does the ball count unit continuously count through the balls in play?... Yes, the Pinball Gods can be nasty...

Looks like something happened when you were adjusting the contacts on the ball count unit... You might want to go back and double check those contacts. So, at this point, the ball count stepper has stopped continually counting through balls 1-5, and now it just resets? And the score motor keeps running after it goes through a partial reset...

I'll check the schematic, and post some ideas later in the day... Next question to answer: Why does the score motor keep running?

Go back and check the 6th ball count switch (RED-GR & RED-BLK wires) - that supplies power to the O,P, Q relays. I suspect it isn't closing properly after you put the Q-tip in there.

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At this point, the machine is powered on, ball is in the outhole kicker shooter, start button is pressed, all score reels reset, ball count stepper resets, credit is deducted from the credit reel, and the score motor keeps running...

Looking at the schematic, you mentioned the AB relay was not energizing. So, one of the switches in the AB relay coil circuit is at the ball count unit, which is a wiper switch on the ball count stepper. Look at the following wiper switch on the ball count stepper:

Ball count wiper switch - switch with orange/white/red wire and white wire

Manually operate the ball count unit to see what is happening with those wiper switches. Clean the wiper switches as needed...

In turn, there is a switch on the AB relay that sends power to the score motor. Check the following switch:

AB relay switch - switch with red/white wire and slate/red wire

I'd like to get the machine back to when it did a partial reset with the score motor stopping after the partial reset...

I just found the switch on the schematic...it will measure as a zero ohms because of the normally closed R contact in parallel.

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Good news! Maybe the switch was opening due to vibration as the Ball Count plunger was operating...which would have stopped O from locking in.

Glad we are getting there!

Now my old favorite question ... is that O relay locking in?

You'll need to check the circuit that includes the right flipper switch to see why the ball won't launch...

First check the ball shooter solenoid circuit. Check the following:

W relay switch - switch with red/white wire and green/yellow wire
Score motor switch 2C - switch with green/yellow wire and slate/red wire
O relay switch - switch with slate/red wire and brown/red wire

Then check the circuit with the right flipper switch. Check the following:

Zero position ball count unit switch - switch with red/green wire and red/white wire
Right flipper switch - switch with red/white wire and green/red wire
Q relay switch - switch with green/red wire and yellow/red wire
O relay switch - switch with yellow/red wire and slate/red wire

Inspect, adjust (*if needed) and clean those switches and see what happens...

I don't recommend adjusting switches yet - you may cause more problems (no offense intended ). Try and isolate the problem first.

With a ball in the shooter lane and game on ball 1:

Is relay O locked in?

When you press the right flipper button does the motor start?

Congratulations! I need a beer after this one... Now give the machine a good workout by playing a ton of games on it. It will probably need a slight tune up, but you can have fun fine tuning it... Looks like this machine had multiple issues - the 6th position ball count switch, the W relay switch and the tension spring on the ball count unit... Now you can start a Gottlieb Pro Football club! This motivates me to get my Pro Football out of storage... Enjoy!

lol me too!

Glad to hear you got it working in the end - well done!