| There are 4 basic IDM models: the 100A, 100, 110 and 120.
Within these 4 models are at least 8 different PCB (Printed
Circuit Board) layouts, and IDM-110's and 120's often have the
same PCB in them.
All IDM's are completely interchangeable with each other, and
any IDM can be used in any model year truck.
The 100A, (Right, Top) used in 1994 and early 1995 trucks, has a
completely different layout compared to all the later models.
Its layout is extremely disorganized, with components that make
up one sub-circuit often scattered around on opposite ends of
the board.
The boards consist of 4 layers of copper, from which the
traces are cut: the top and bottom layers are visible, the 2
inner layers are sandwiched in the middle between insulating
layers of epoxy reinforced fiberglass.
Right, Center -> IDM 100
Note that very few of the PCB traces are visible in the 100
and 120 as compared to the 100A. Although the later models do
have fewer traces, they also have many of the traces run between
the layers of the board, giving better shielding from
electro-magnetic radiation.
The square cutouts in the boards are where heat sinks are
fastened to the bottom of the case. The round hole is for the
heat sink of one of the inductors (coils) for the 110V power
supply. Right, Bottom -> IDM 120 |
