I guess I remember the 1985 edition of Break the Bank best among those who have posted in this thread so far, so here's how the two formats worked:
In Version 1 (the stunt format), contestants played for time to complete Beat-the-Clock-type stunts in the show's Prize Vault, with the first couple to solve two Password+/Super Password-type puzzles winning the chance to play. Successfully completing each stunt won the player the prize connected with that stunt and an electronically-coded "bank card," which they could then choose to try in a "combination lock" for the grand prize of all the money in the "bank" for that program. (The "bank," in this version, BTW, started at a combined cash/prize total of $20,000 and was increased by approximately $2,000 a day until it was won, with the increase consisting of $500 in cash and one or more additional prizes.)
The players could play for any prize at any time during their time in the show's "Prize Vault," and once they won a prize, it was theirs to keep, no matter what they chose to do with its corresponding "bank card." Usually, after their "Prize Vault" play was over, they would be offered a cash buyout for their "bank cards," but the "buyout" option would differ from day-to-day. (Typically, though, they would be offered the largest buyout for all of their "bank cards," and smaller amounts for whatever card(s) they may have left after one or more unsuccessful attempts to open the "combination lock" for the grand prize.)
I believe there were a total of 50 "bank cards" available in a game between those a player could choose from that were connected to the prizes and the extra cards that were available from the "Number Jumbler," which was connected to a randomly-selected prize in the "Prize Vault" (Selecting that prize gave the player a chance to press a button that would display a number from 0 to 5 on the "Number Jumbler's" readout; the player would then get to take that many cards from the card rack in front of the device.) However, only one of those cards was worth anything (the "bank" amount for that program); the others were completely worthless!
When the players did choose to try their "bank cards" in the "combination lock," a gimmickly "code number" would first come up on the lock's display (such as "940162"), followed by the words "WRONG CODE" if the card was not the one that was good for the grand prize, and "BREAK BANK" if it was. If it was the latter, the contestants retired from the show with their winnings; otherwise, they would return as "champions" on the next day's program.
In the "master puzzle" format that was used in the latter part of the show's run, there were actually two methods of play. For both, the contestants first earned one "bank card" for winning the main game (which also had a minimum $2,000 cash payoff) and could earn up to 9 additional "bank cards" by solving the "master puzzle," depending on the number of revealed clues that were needed for a solve.
In the early episodes of this format (which I'll call "Version 2.0"), all of the "bank cards" were in one big rack. The players first took from the rack all of the cards they won on that day's program and tried them one-at-a-time in the "combination lock" until they either ran out of their cards or until they succeeded in breaking the bank. However, instead of code numbers, a description of a prize (such as "REFRIGERATOR") would appear on the lock display if it was not the card that broke the bank, and the player would win that prize. ("BREAK BANK" would appear on the lock display as before if the player did select the correct card for the grand prize.)
Later, that format was changed as follows (in what I will call "Version 2.1"):
1. For a couple winning their first game, the card rack would have its full compliment of 50 "bank cards." Out of those, 48 cards would have coded prize descriptions on them (unknown to the player until they were inserted into the "combination lock"), one would be encoded with the word "BANKRUPT," and one would be encoded with the words "BREAK BANK."
2. The couple would select the first card they won in the game and/or the "master puzzle" round (they could win up to 10 cards going in as before) and the card was inserted into the "combination lock." If the display came up "BANKRUPT," the game was over, but the couple would return as champions on the next program, and if the display came up "BREAK BANK," they would retire from the game with the grand prize and their game winnings.
3. If a "prize description" of some kind came up, the couple could then choose to stop the game, take the prize, and return as champions on the next program, or select another "bank card" in an attempt to win an additional prize or break the bank (assuming they were entitled to additional selections). If they chose to play on and picked another "prize description" card, that prize was added to their potential winnings, and they could then choose to either stop the game with their two prizes, or continue playing, etc.
4. The game would end when: a) a couple chose to stop playing voluntarily, in which case they would keep their prizes won up to that point, but forfeit any potential winnings from remaining card selections; b) a couple picked the "BANKRUPT" card, in which case they would lose all of their prizes accumulated up to that point and all of their remaining card selections, if any; c) a couple picked the "BREAK BANK" card, which would win for them the day's grand prize and end the game; or d) a couple selected all of the cards they had won on that day's program without picking either the "BANKRUPT" or "BREAK BANK" cards.
5. If a couple did not break the bank during play, they would return to the next program as the current champion. If they then won a second game, they would play again as above, but the number of "bank cards" in the card rack would be reduced by the number of cards they had used in their previous appearance(s). (For example, if a couple picked six cards from the 50-card rack in their first attempt in playing the game and failed to break the bank, then won the main game again the next day, they would start with 44 cards in the rack for their second attempt to break the bank.) However, the "BANKRUPT" card would always go back into the rack if they were unfortunate enough to pick it during their last appearance.
And that's what I get for working second shift at IRS during that time, which let me watch those morning game shows!
Michael Brandenburg
(Now where's my "20 Years of Service to the IRS" commemorative plaque?)