Here is a Japanese 1943 built ‘Morse code trainer’. The chrome wheel has bumps and flats which are read out by the flexible metal arm switch.

It looks to me like tube #12 in the schematic is just a “noise generator”, like the contacts that feed its grid “drag” on the chrome wheel. That’s

my guess. Tube #1 is the tone generator which goes right to the output transformer. The two tube plates are paralleled. Some years back i

transcribed the characters sent. Some are uniquely Japanese not used elsewhere in the world. I only have the one chrome code wheel which is

frozen on the axle anyway. A clockwork spring inside, cranked up, plays it for a few minutes.

-Hue Miller