Keyboard input does not work with Teletype Model 15 with 92222 Filter

[John-Nagle]

Keyboard input drops bits when the keyboard used is a Teletype Model 15 with the 92222 Filter. This is an RF noise filter present on some Teletype machines. The board design provides 24VDC for the keyboard but only draws 5mA through the keyboard contacts. That may not be enough with the filter's added capacitance. The board may need a resistor to add some extra load.

[John-Nagle]

This is the filter assembly, with bracket. It's attached above the keyboard contact cam unit. Some Model 15 machines have this, and some don't.