Modifications to bingos were common, but usually they were disabling score levels, features, or tweaking the proportioning to make the game more profitable.

In the San Francisco bay area, heavily modified united games were common, and I recently went through a Triple Play and wound up documenting what they did.

In summary:

1] scores replaced with yellow, red, white and blue boxes with team names screened onto the replacement glass. Each box corresponded to 2 positions of the score unit, and payouts were modified with max being 100.

2] all cards score separately permanently enabled and status boxes removed from backglass

3] reflex unit disabled.

4] extra ball unit stepping was done during game cycling and accumulated from game to game (extra ball futurity). You could elect to take all accumulated extra balls by pushing the extra ball button on the cabinet front. You could not specifically cycle the game for extra balls.

5] the game operated on quarters and would only accept one coin. If you inserted a second coin, the game reset. You got all three cards enabled for a coin. Credits could be used to cycle game for features and extra balls.

6] if you played credits, you got one card enabled per credit.

7] they paid off credits in dimes, so it made sense to always reset the game with a quarter. Credits were not decremented when a coin was used.

8] the motors shut down after each cycle unless number selection enabled. An added button on the cabinet front was like a bally R button - push to scan for winners.

9] the spell name feature unit was modified to reset to "triple pl". Two rollover activations when spell name feature was lit got you 5-in-line scores scored on card 1 replay counter, so card 2 or 3 wins would count as well.

10] score extra step disabled.

all the above was done using one extra relay, one extra door button and modifying/reusing existing units. Moving original wiring to different switch stacks or splicing different color wires onto each end of an unneeded original wire to reduce new long wire runs made working out the changes ... interesting. Wipers were restacked and repurposed on the extra ball unit, and I changed it more to remove the necessity of having a flexible jumper wire directly connected to a wiper finger.

Not all Triple Plays were modified the same way, and the backglass with the team names and "United's pennant" in the top left seems less common.
bg-triple_play_pennant (resized).jpgcab-triple_play_pennant (resized).jpgsi-triple_play_pennant (resized).jpg

I think the primary local requirement was making it a one coin game ... tho if you had credits you could cycle off as many of those as you wanted. Since you weren't feeding in multiple coins with many of them doing nothing useful, that got rid of much of the obvious gambling aspect of the game.

one coin per game also eliminated cycling for extra balls, so rather than getting rid of them they came up with the futurity change.

I don't know if the 100 credit max win was a legal thing or just balancing the game to keep it profitable. Some locations in washington went with a max win rule, so you see backglasses with the scores scraped out and replaced with letters. A score card told you how much each letter was worth. Cycling the game beyond a certain score level didn't really make sense since the payout was capped. I guess if people actually calculated the theoretical payback, nobody would play the "spin the wheel" game in vegas.

this triple play is the only machine I've seen with extensive rule changes. A manual and schematic that shows the changes is being finalized.

if you're curious about how the changes were done, a schematic and manual for the modified game are available on https://bingo.cdyn.com/oddities/pennant_triple_play/