Does the trip relay bank with the S/Start relay in it ever reset? The tripped S/Start relay will keep the Score Motor running (which will keep targets resetting) until the bank resets. That requires the S Armature switch to be closed (below the trip bank) and switches on the Ball To Play Unit to close.

/Mark

It should count down to zero, then count up to five at the start of a new game. Yours might be skipping the count down part. There are two paths into the Subtract Balls To Play solenoid:
Flipper Clown Balls to Play (resized).jpg
The upper path through the S/Start relay switch is used during reset and the lower path is used during game play. If you jumper around the Zero Position switch (by connecting yellow+red to green-yellow) does it count down?

Have you experimented with the circuit in reply #9? That would be a good place to start.

I'm not sure which lights you're referring to. There are three Left Target When Lit rollover lights that work together, and three more for the right target. They should be lit when the Left Target Scoring Unit is in position 0:
Flipper Clown target scoring lights (resized).jpg
The Left and Right Target Scoring Units are steppers under the playfield in the back (see: https://gottliebpin.com/archive/GTB-Ref/191/gtb-pb191-underpf.jpg). Do they ever advance past the 1st position?

This is a pretty cool circuit that I haven't studied before. I need to spend some more quality time with it to grok it.
Flipper Clown W relay (resized).jpg
But I think the key is the W/Win relay coil in the upper left. That should fire to award an extra ball before the Left and Right Scoring Units reset. There are two ways to fire that relay coil. One is through a switch on the P2/Right Target Scoring relay which fires when the right side is being awarded. The other is through a pair of wipers on the Right Target Scoring Unit that complete the circuit when the unit is between steps 3 and 15.

When you set the left target first, it's the circuit through the P2/Right Target Scoring relay switch that must complete to fire the W relay once the right side has done its thing. If that never works I'd start by checking the P2 relay switch in the red box.

EDIT: The P2 relay switch on the lower right would be the next thing to check. Both P2 relay switches need to close to fire the W/Win relay when the left target is set first.

This is the most interesting circuit I've studied in a while. It's a unique problem and a very clever way of solving it. (More) Kudos to Mr. Neyens.

For those who aren't familiar, there are two columns of lights on the playfield (left and right). Hitting the Roto Targets or appropriate rollovers will turn on one light in each column. Once both columns have one light on the game will award an added ball if the light in the right column has a higher value than the light in the left column, then both columns will be reset.

It's common and relatively easy to determine if two things are "equal" with circuitry. Most games have a match circuit for example that awards a replay if a digit of the score matches (or equals) the position of a hidden stepper.

What's unique in this situation is that the game must evaluate a "greater than" function which is more complicated and interesting than an "equal to" function. To explain how that's done I've simplified the schematic above and animated it.

In the first animation both columns of lights start in their reset positions as shown in the schematic above and the left Roto Target is hit while 7 is showing. The result is that the Left Target Scoring Unit takes seven steps:
Left side first part 1.gif
Note that the Left Target Scoring Unit has two pairs of wipers that move together as the unit advances. Also note that the L2/Left Target Scoring relay is active while the Left Target Scoring Unit advances which closes the two L2 switches in red.

The second animation picks up where the first animation left off. The left column has the #7 light on and the right Roto Target is hit while a 12 is showing. In this case a ball should be added. To achieve this the W/Win relay in the upper left corner must be active when the advancing stops.
Left side first part 2.gif
The P2/Right Target Scoring relay is active while the Right Target Scoring Unit is advancing which closes the two P2 switches in red. When the Right Target Scoring Unit steps to position 8 (which is one greater than the Left Target Scoring Unit at postion 7), a circuit is completed that fires the W/Win relay as shown in red. When it steps to position 9, the circuit to the W/Win relay is broken, but the W/Win relay Lock In circuit in red keeps the W/Win relay active. The Right Target Scoring Unit continues stepping to position 12.

In this scenario (when the left column light is set first) the Right Target Scoring Unit is essentially compared to the Left Target Scoring Unit at each step as it advances to position 12. The Left Target Scoring Unit has a 2nd wiper that points to the position one higher than the current Left Target position (8 in this case) and once the Right Target Scoring Unit reaches it a circuit the the W/Win relay is completed.

The other scenario (when the right column light is set first) is even more interesting. In this animation both light columns/Scoring Units are reset and the right Roto Target is hit while an 8 is showing so the Right Target Scoring Unit takes 8 steps.
Right side first part 1.gif
Note that the P2/Right Target Scoring relay switches in red close while the Right Target Scoring Unit advances although they have no effect in this situation (when the right side sets first).

The second animation starts with the Right Target Scoring Unit in position 8 when the left Roto Target is hit while an 11 is showing. In this situation no ball should be added since the right side (8) is not greater than the left side (11).
Right side first part 2.gif
But surprisingly, when the Left Target Scoring Unit takes its 1st step to position 1, it completes a circuit that fires the W/Win relay. The Lock In Circuit in red holds the W/Win relay active while the Left Target Scoring Unit takes more steps.

But when the Left Target Scoring Unit reaches position 8, which is equal to the Right Target Scoring Unit, it completes a circuit which activtes the O/Left Target Lose relay. The O/Left Target Lose relay in turn opens a switch in the W/Win relay Lock In circuit which allows the W/Win relay to relax. By the time the Left Target Scoring Unit reaches its last step the W/Win relay is inactive even though it activated briefly during the steps up.

The circuit essentially assumes that a ball should be added (by firing the W/Win relay) and looks for the condition that would invalidate that assumption (if the O/Left Target Lose relay fires).

To make it even more interesting note that the Left and Right Target Scoring Units wired back to back are used to fire two different relays (W/Win and O/Left Target Lose) by using the L2/Left Target Scoring relay and P2/Right Target Scoring relay switches to direct which relay is using the Scoring Units.