: The schematic includes additional circuitry for Status LEDs on the Numerical Lock and Capitals Lock keys, which were not present on the original IBM Model F. PCB and Material Specifications
For those looking to restore a unit, detailed IBM restoration guides can provide visual context for reassembling the plunger assemblies and the metal backer plate found in these vintage units. KB 5150 OPERATOR'S MANUAL - minus zero degrees kb 5150 schematic diagram top
: One-way communication from the keyboard to the PC. : The schematic includes additional circuitry for Status