(Topic ID: 216845)

GTB "300" help needed

By Steve_B

1 year ago

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  • 4 posts
  • 3 Pinsiders participating
  • Latest reply 1 year ago by Steve_B
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Top score A I relays (resized).jpg

#1 1 year ago

I have 3 questions on a 1975 GTB "300":
1). What relay or switch activated the A relay. This relay alternates the lights along the right side rollovers.
2). What relay or switch alternates the 3 target lights.
3). Is there suppose to be a capacitor in a small Jones plug to the right of the transformer fuse.

Thanks for the help.

#2 1 year ago

This is from the Top Score (2 player version of 300) schematic so it may not be exactly right for 300:
Top score A I relays (resized).jpg
1) The A/Alternating relay is activated by the KS/Advance Unit relay which is one of those very small AS style steppers.
2) The right side target lights are controlled by the EX/2nd or 4th Ball relay. The left side target is always on. All targets also go off briefly as the score motor turns.
3) The capacitor, along with a diode and resistor are part of the delay module, typically mounted on a jones plug, to delay the firing of the I/Add Bonus Delay relay. These are used for example to let a spinner stop spinning before awarding points selected by the spinner.


#3 1 year ago

Heres a link to a drawing of the 'bonus delay unit' from a 'Top Score' as a reference.


#4 1 year ago

Mark, thanks for the information. I'll check on items 1 and 2 later this week. The bonus delay sounds similar to the one in Buccaneer.
Oldpins, thanks for the link. I should be able to build that module if I can't locate an original.

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