Ditto Damen
Its not the old Dumont. They were gone by the mid 60's.
The name came back in the 70's or 80's with cheap chassii. That is
to new for this type CRT.
I think its a rebuilt & they decided to use the name. Its probably a
" low focus" type many used at the time & built by RCA.
73 Zeno
LFOD !