Mainboard 81-184

The 81-184 boards are part of the "Universal" boards. They can be found in the 4X, New 2, ...

4X

This is a closeup of the 4X board. Note that U53 is populated and that U60 has resistors replacing it. This is required for the Drivetec Drives.	This is a New 2 board which does not have Drivetec drives and does not have U53 but does have U60.

Mods

74LS139 Mod

If you find a 74LS139 in the front "SPARE" U70 socket you may have a Mod to allow for more than two drives. See page 93 of Micro Cornucopia Apr-May 1986 for details. Link here.