Did the Spelling B I bought for you include the booklet? I think the manual for the one on datamath is for the 2nd revision hw. Speaking of the 3.9MB one here http://www.datamath.org/Edu/SpellingB.htm
If you have it, is it equal? On MAME, I'm getting mismatched numbers, for example: 26 = nurse 85 = broom 64 = chain
It also locks up on me sometimes, I'll look into that. The Hangman game mode works fine.
*edit* WIP driver: http://git.redump.net/mame/tree/src/mame/drivers/tispellb.cpp also, datamath includes Math Marvel in the same list. but you see I didn't put it in the driver comments. It actually is the same hardware as DataMan: 1 MCU only, no TMS0355 ROM.