I can’t think of any effect of the typing unit on the keyboard other than something that would keep it from working at all
(like a busted/wrong drive gear).
Reference -
Please give us more info.
If you type the same character over and over do you always get the same result?
RRRRRR YYYYYYY EEEEEE TTTTTTT
What do you you get when typing BLANK over and over?
Isolate the problem between the code bars, transfer levers, and transmitter contacts.
You may want to manually rotate the motor to see things in slow motion. Pull the top of the fan (on the right end of the motor) toward you.
Watch the code bars at the right side-
Type E LF SP CR T yo make one code bar at a time move.
Type E A U K LTR V M O T to make 1 2 3 4 5 4 3 2 1
code bars move together
If the code bars are behaving OK -
Type the same thing while looking at the transfer levers (to the right of the transmitter contact box)
If they aren't behaving you probably have something gummed up from old grease or a missing spring.
If the transfer levers are behaving OK you probably have dirty contacts, loose connection, or a bad noise suppression network (inside the transmitter box)
Watch a loop current meter as you turn the motor by hand.