[Boatanchors] code practice machine

[William L Howard]

I just got what  think is a WW II German code practice machine. Data
plate says GLS and some serial numbers, factory numbers. In side the
case is the schematic, labeled "Schaltbild fur
Glimmrohrensumme???",(Schematic for glow tube???)  The schematic is in
rather poor shape and the top part is missing. I think it is a "glow
tube" something. Has sockets for a key and two headsets. it is missing
the glow lamp.

Do any of you have any information on this set, and maybe a schematic
that is complete? I also need the glow tube? lamp? Do you have any
source for one of these?

Thanks,
Bill Howard