Very Early Yaesu Musen Co. Amateur Radio Equipment

Note that the block diagrams of the FT-100B and the FTDX100 are almost identical. Both germanium and silicon transistors were used in almost equal quantities, unlike the original FT-100 which used nearly all germanium devices, and the later FT-101 which used nearly all silicon devices.

By the time Yaesu released the FT-100B they had refined their solid state transceiver design considerably, having used the FT-100's Mark 1 and 2 to iron out problem areas. Being at the forefront of technology when it was first released, the original Mark 1 FT-100 did have a few teething problems, to the extent that Bail's published their own three page Trouble Shooting Guide for it.