Model and ROM information

Information regarding Model type, PCB code, ROM marking, ROM version and checksum is captured here.

What Kind of Model 100 or Tandy 102 do You Have?

Model 100

The first M100s were released with a custom ROM pinout, in agreement with the published schematic. Over time, Radio Shack changed the design to use standard ROMs.

This is the way the T102 and T200 were designed. The later M100s do not agree with the published schematic. This causes an issue for anyone who wants to make something that plugs into the ROM socket! M100s have a code on their ROM chips, as well as in the silkscreen on the PCB. Below is a list of known ROM codes, and the boards they go into. Partial list of M100 PCB and ROM codes

Board Code ROM type ROM Code Comment

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PLX110CH1X custom LH535618 early North America PLX110EH1X 27C256 compatible 3256C07-3J1 late North America PLX120CH1X 27C256 compatible 3256C05-3E1 European/Italian