The lit lane is determined by the spinner mini stepper, do you see something checking its five contacts anywhere?

My guess from that circuit's connection to the ball count adjustment is that might be the award bonus (at end of ball), not the advance bonus (which probably isn't a relay itself, just a stepper coil), but I'm not super familiar with Gottlieb lingo from that period

Hi jeffc
I bet zacaj did look-up in the "lights" section - the KS-Ministepper controls the lamps of this feature --- and through the KS-Stepper does activate the D-Relay (if the stepper is in position) - so at "You get TWO bonus" situation: NOT ONLY "marked green" the "E-Relay" is activated --- ALSO the "D-Relay is activated ("marked red stuff") --- and the snippet of schematics You show in post-1: I see "Add Bonus Unit" is pulsed TWO times, greetings Rolf

0Surf-Champ-Work-12 (resized).jpg

Yes, the schematic snippet you included in post #1 does show the two-bonus-advance function. This is implemented in the D (500 point) relay and the E (500 point and add bonus) relay.

Note the make/break switches that are wired to the ADD BONUS UNIT coil, shown in your snippet just to the left of motor switches 3C and 1B. One of these make/break switches is on the D relay, and the other one is on the E relay.

When the D relay pulls in by itself, the motor 1A switch on the far right of your snippet pulses the M (100 point relay) five times. The D make/break switch changes state, but no pulse is provided to the ADD BONUS UNIT coil because the E relay make/break switch is not pulled in. This is correct, because the D relay is for 500 points only (no bonus add).

When the E relay pulls in by itself, the motor 1A switch on the far right of your snippet pulses the M (100 point relay) five times. The E make/break switch changes state, which allows the single pulse provided by the motor 3C switch to be sent to the ADD BONUS UNIT coil. So, the ADD BONUS UNIT coil steps up one time (1,000 bonus). This is also correct, because the E relay is for 500 points and one add bonus.

Now, when both the D and the E relays pull in at the same time, they both enable the motor 1A switch on the far right to pulse the M relay five times. Also, the single pulse provided by the motor 3C switch is sent the ADD BONUS UNIT, stepping it up one time. And, the single pulse provided by the motor 1B switch through the pulled-in D make/break switch is also sent to the ADD BONUS UNIT switch (via the pulled-in E make/break switch) stepping it up a second time.

Thus, the "extra bonus" function occurs when both the D and E relays are energized at the same time - you get your 500 points, and two add bonus.

- TimMe

In case you are interested, I also want to provide some information about the GTB score motor sequence, which is heavily used in the schematic snippet you provided in post #1. Although the score motor itself looks complicated, it is doing a fairly straight-forward thing.

Essentially, each cycle of the score motor provides five pulses via the 1A switch stack (the switch stack that rides the bottom cam). Nearly all of the other switch stacks located at various positions around the cam actuate just one time per score motor cycle. Most of these single actuation pulses is overlaid on top of one of the five pulses coming from the 1A switch stack. These overlaid pulses are of a longer duration than the 1A pulses and actually begin slightly before a given 1A pulse, and last a bit longer than that 1A pulse. Thus, these are known as "masking" pulses. In the blue section of the following chart, you can see how this works:

Gtb_Motor_Chart (resized).JPG

Many GTB score-motor circuits are implemented by having the circuit originate at the 1A switch stack, which always provides a properly-timed five-pulse train that allows the stepper units to reliably step up to five times quickly in succession.

If less than five pulses are wanted for a particular function, the five-pulse train is wired in series through one or more of the masking switches. If only one or two pulses are needed, then the masking switches are usually configured as normally open (NO), which enables a single 1A pulse in the train when that corresponding masking switch closes. If three or four pulses are needed, then the masking switches are usually configured as normally closed (NC), which disables a single 1A pulse in the train when that corresponding masking switch opens.

In your game, this function is put into full use because of the five rollover buttons that control how much score is given by the kick-out hole. Note how each rollover control switch is wired to the 1A pulse train through one of the score motor masking switches. If you read the schematic from the bottom up, and refer to the chart, you can see that motor positions 1D, 2C, 3B, 1B, and 3C mask each of the five pulses, in sequence order. You don't often get to see that on a single GTB schematic.

Since the 1B and 3C masking pulses are already in place for the rollover/kick-out hole scoring, they have also been used to provide the source of the bonus unit single-add and double-add, which occurs at the 4th and 5th pulses of the 1A five-pulse train.

- TimMe

Tim is a freaking national pinball treasure.

I'm continually astounded at how much genius was involved by the engineers that designed these games, making them do what they do with steppers, relays and switches.