With the ball count unit in the position shown on the photo you should have continuity across the circled terminals. If not, then suspect dirty/worn rivets on the disc or the jumper wire connecting the wiper fingers.

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Are you measuring ohms or using the DMM's continuity tester?

What was the resistance in ohms measured across the contacts.

Be careful using the continuity checker on your DMM as you may get false readings. The DMM continuity checker will beep when the measured resistance is below a defined threshold (say < 40 ohms). On EM's it is possible that you will measure this resistance back through the transformer giving you a false continuity reading.

In the circuit below (taken from Pro Football) the DMM continuity checker would beep if you were to probe across the OPEN "S" relay contacts because the measure resistance would be < 40 ohms (through the highlighted path giving you a false reading) even though the contacts are open. If you were to measure resistance you would measure the combined resistance of the RESET BALL COUNT UNIT coil and the 25V transformer secondary (low ohms).

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From your video it looks as if Q and O are energized. Pressing the right flipper button should cause the motor to run through the highlighted path in picture below but that doesn't appear to happen.

Things to check:

Is the ball count unit being advanced by the P relay?

If you manually step the ball count unit off the zero position does the flipper button then activate the ball kicker and eject ball (put ball in outhole first!)?

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If the ball count is not stepping then the Zero Position Ball Count contacts will stay open and there will be no power to the flipper contacts. The Ball count should advance when P is operated through a P relay contact and Motor 4C switch.

What happens if you manually operate the P relay?

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Check the switches in the highlighted path in previous circuit - for some reason the Add "Ball Count" Unit coil is not being activated. For a quick check coil and mechanical operation run a jumper from the RED-GR wire on the 6th POS "BALL COUNT" UNIT switch to the OR-BL wire on the ADD "BALL COUNT" UNIT coil. This will bypass all the intermediate switches and wiring allowing you to prove the coil is ok and functioning properly.

The RD-GR wire is on the other contact blade of that switch and is common to the 6th position and zero position switch See arrow below.

Anyway it's good that you have proved the coil functions OK. So next check the AB, Motor 4C and P relay contacts in the highlighted path (see previous post)

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From the video it looks like O relay is not locking in. Check the contacts in the highlighted path below.

Also check the MOTOR 4C switch as well - if that pulse is too short or contacts are dirty then O Relay won't operate properly in the first place.

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From the video, it still appears that the O Relay is still not locking in ....

What happens to O if you manually operate and hold in P?

So it appears that you have proved the O relay lock circuit functions when manually pressing contacts which proves the coils is good.

Lets work backwards here...we know O doesn't lock in. So with the game in the reset state (no ball in outhole) manually operate O relay and it should stay locked in. Manually operate either the L, M or N relay and O should drop out. Lock circuit proved!

Assuming the O lock circuit functions we now need to test the operating circuit for O. So again with the game in the reset state (no ball in outhole) manually operate and hold in relay P. The motor should turn and and when Motor 4C pulses Relay O should operate and lock in.

Report back

I'm still convinced it's an issue with O relay not locking in.

We now know P is operating OK because the Ball Count Unit is advancing when the ball is in the outhole.

If O doesn't operate or lock in long enough the ball doesn't get kicked out and the cycle repeats since Q is still operated by a ball on the ball return switch.

So....if you manually operate O what happens? Does it lock-in? Does the ball get kicked out?

Something else to check...with the power OFF turn the motor manually and check the Motor 4C switch with BL+BLK and BR+BLK wires. Make sure that the upper contact has some lift when operated by the motor cam and that the switch contacts are clean.

BTW don't use a DMM continuity tester on EM's you will get false readings through alternate paths via the transformer. Continuity tests will be when the resistance measures is below a set threshold (IIRC about 40ohms on Flukes) - the resistance of the transformer winding is much less than that so will trigger a beep.

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I forgot that the flipper button needs to be pressed to launch the ball

Which 4C wire did you disconnect ?

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

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.

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.

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 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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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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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?

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?

lol me too!

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