Cracking Trivia Madness (1985)

M. Kramer Manufacturing's bar-top trivia with two chip formats on one board. Long listed as undumped; turned up on archive.org in 2021. 3,790 questions across 8 category chips. The True/False chips' phrase dictionary hid inside a graphics ROM.

April 19, 2026 · crack, kramer, thunderhead, trivia-madness, z80

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Trivia Madness

M. Kramer Manufacturing / Thunderhead Inc. · 1985 · Z80 · 8 category chips · 3,790 records

The Cabinet

Trivia Madness¹ shipped in 1985 from Thunderhead Inc., built on a countertop board designed by M. Kramer Manufacturing of Asbury Park, NJ. Kramer was a tiny player in the bar-trivia boom, their catalog totals only two known cabinets, the other being the almost-impossible-to-find LA Beer Trivia Challenge, an Anheuser-Busch-licensed machine that debuted at the 1985 AMOA Expo. Both run the same basic hardware. The trivia was the product; the Kramer board was the delivery vehicle.

For decades Trivia Madness was on the “never dumped” list at mameworld.info/maws . The cabinet was rare enough, and Kramer obscure enough, that nobody with an EPROM reader had ever pulled its chips, until May 2021, when an uploader called “Sketch the Cow” dropped a complete dump onto the Internet Archive as arcade_trvmadns . Playable in a browser immediately. Extractable, with effort.

The Data

All 3,790 records browse at /browse?source=kramer_trvmadns . a mix of True/False (2,124) and Multiple-Choice (1,666) questions across eight category chips.

• Extractor: scripts/thunderhead/extract.py
• Original ROM dump: archive.org/details/arcade_trvmadns
• MAMEWorld unMAMEd entry (historical): non_other80.html

How We Cracked It

The Hook: Two Formats, One Cabinet

The Trivia Madness board accepts question ROM chips in any of 16 bank positions. Operators could mix-and-match chips across categories. Most bar-top trivia cabinets of this era use one format; Kramer used two, depending on the category:

• True/False chips (sex, soaps, rebel, star trek) store short statements followed by .*T or .*F. Players answer TRUE or FALSE.
• Multiple-Choice chips (entertainment, sports, TV, travel) store four-option records: \<question>*<correct>*<wrong1>*<wrong2>*. Players pick A, B, or C.

Same cabinet, same Z80, same ROM socket, the game code dispatches on a marker at the start of the chip (“MC” for multiple-choice, a plain \ for True/False).

The True/False Format

TF chips have no header. Records run top-to-bottom:

\SEXUAL ACTIVITY ELICITS<HORMONAL RESPONSES.*T
\A WOMAN CANNOT RAPE<A MAN.*F
\THE CLITORIS HAS OTHER<PURPOSES BESIDES<PROVIDING PLEASURE.*F
\KAI TEK AIRPORT<IS IN CHINA.*T

• \ marks the start of a record.
• < is a display line break, the monitor wrapped text at fixed character positions and the designers pre-computed where to break. Stripped to a space on extract.
• .*T or .*F terminates the record with the answer.

Bytes in the 0x80-0xFF range inside a TF chip are inline word tokens. Unlike the MC chips, TF chips carry no dictionary of their own, the Z80 dispatches through a board-wide phrase table baked into one of the program ROMs.

Finding the TF Dictionary

An initial pass at the TF chips left every question peppered with high-bit bytes that we couldn’t expand. The dictionary had to exist somewhere, the cabinet obviously renders full English on screen. but program ROM u5 (the main Z80 code) held only code, strings, and the attract-mode text. We almost shipped with the TF tokens stripped and moved on.

The fix was to scan every ROM on the board for a specific structural signature: a byte sequence where a high-bit token byte (0x80, 0x81, 0x82…) is followed by a short ASCII phrase, which is followed by the next sequential token byte, and so on. The pattern lands on a real dictionary and ignores incidental ASCII runs. Exactly one hit across 40 KB of ROM:

u6 “green” at offset 0x1EC0, a 49-entry phrase table:

  0x80 WHO   0x81 WHERE  0x82 WHAT  0x83 WHEN  0x84 HOW
  0x85 WAS   0x86 THE    0x87 IN    0x88 OF    0x89 IS
  0x8A AS    0x8B AN     0x8C WHICH 0x8D AND   0x8E HAD
  0x8F TO    0x90 ON     0x91 ARE   0x92 DID   0x93 FOR
  0x94 HAVE  0x95 WITH   0x96 FROM  0x97 YOU   0x98 SPENDING
  0x99 WHO WAS THE       0x9A WHEN WAS THE
  0x9B HOW MANY          0x9C 19   0x9D LEAD
  0x9E WHERE WAS THE     0x9F WAS THE          0xA0 MOST
  0xA1 YEAR              0xA2 HIGHEST          0xA3 THAT
  0xA4 TIME 0xA5 ONLY    0xA6 I SAY LA         0xA7 I SAY LA WHEN
  0xA8 AT   0xA9 I'VE    0xAA GOT   0xAB I'M   0xAC LONG
  0xAD IT'S 0xAE DAY     0xAF WORK  0xB0 PARTY

u6 is labelled “green” on the board, ostensibly the green colour plane of the character ROM, but Kramer quietly parked the dictionary in the tail of the file where the graphics would otherwise be all 0xFF padding. That is why the earlier pass missed it: nobody looks for phrase tables inside a colour ROM.

With the dict applied, TF questions read as full English. Byte 0x86 alone (the most common token, 2,125 occurrences) is “THE”, two thousand missing THEs. The MC chips layer their per-chip 0xC0+ dictionary on top of the same board-wide table, so words like “WHO WAS THE” get a token in the global table and chip-specific entries like “ALL MY CHILDREN” get a token in the per-chip table.

About ~130 high-bit bytes in the 0xB1-0xEF range remain unmapped. per-chip category tokens (things like “SEXUAL”, “ONCE MARRIED”, “SOAP OPERA”) we haven’t located a storage site for. Those are silently dropped during extraction rather than rendered as placeholders.

The Multiple-Choice Format

MC chips carry their own per-chip phrase dictionary. The layout:

  0x0000    "MC" magic
  0x0004    category name + "*"
            0xFF padding (~250 bytes)
  0x0100    Token dictionary
            - Each token entry is <byte 0xC0-0xFE><ASCII text>
            - Runs until the next 0xC0-0xFE byte or 0xFF padding
  ~0x0380   0xFF padding
  ~0x0400   Records
            \<question>*<correct>*<wrong1>*<wrong2>*

Reading the Entertainment chip’s dictionary:

  0xC0: 'PLAYED THE TITLE ROLE'
  0xC1: 'WHO RECORDED THE THEME SONG'
  0xC2: ' BALLAD'
  0xC4: '\x86\x9c53'               ← garbage (chained to another token)
  0xC5: 'LORRETTA LYNN*\x82\x85 CHARLIE CHAPLIN\'S<'
  0xC7: 'CHARLES BRONSON'
  0xC8: 'DUSTIN HOFFMAN'
  0xC9: 'BURT LANCASTER'
  0xCA: 'JACK NICHOLSON'
  0xCB: 'CLINT EASTWOOD'
  0xCC: 'WHAT ACTOR PLAYED'
  ...
  0xE4: 'JAMES'
  0xE5: 'FIRST'
  0xE6: 'OSCAR'
  0xE7: 'JACK'
  0xE8: 'JOHN'

Every chip defines roughly 50 tokens, mostly actor names, common film/music vocabulary, and short connectives. Each category has its own vocabulary because the space savings are category-specific: sports chips define “TOUCHDOWN”, “QUARTERBACK”, team names; travel chips define “CAPITAL”, “OCEAN”, “CONTINENT”.

After token expansion, a record reads:

\WHO CO-STARRED WITH ELVIS IN THE MOVIE, "VIVA LAS VEGAS"
    *ANN-MARGRET*LANA TURNER*RITA HAYWORTH*

Correct answer is always the first field after the question.

What Tripped Us Up

Three false starts before the real solve:

Mis-identifying the MC dictionary. The records themselves contain bytes in the 0xC0-0xFE range (from token references), so a naive dict-scanner that looks for “consecutive 0xC0+ bytes” will latch onto the record section instead of the real dictionary. The fix was to find the first 0xC0 in the file, because the dictionary always sits before the records, the first occurrence is always the real dictionary start.

Looking in the wrong ROM for the TF table. A first pass searched u5 (the main Z80 code) and u7 (graphics) for a phrase table, nothing there. The table lives in u6 (“green” colour ROM), which no one normally scans for text.

Treating TF chips as “dictionary-less”. A second pass just stripped all high-bit bytes from TF records rather than expand them, producing readable-ish English with words missing. That got shipped briefly before the u6 scan turned up the real table.

The Eight Categories

After decoding both formats with the merged dictionary stack, the 3,790 records fall into eight category chips:

The Rebel name is period slang, the chip is Southern-masculine trivia (guns, bourbon, pickups, pop country). Not Confederate iconography, despite the name; just bar-top content aimed at the demographic the operator would drop a Trivia Madness cabinet in front of.

Output

3,790 records across the eight chips. Questions are a mix of True/False (2,124 records) and Multiple-Choice (1,666 records). The MC format carries 2-3 wrong answers; the TF format carries only the opposite boolean.

References

Related

Cross-archive analyses

• Who Stole From Whom: 1,349 plagiarism hits
• The Funny Bits: AI reads 115K trivia questions