This is what you have is one of these:
http://earlytelevision.org/stromberg_table_tv-12.html
Which is a rebadge of one of these:
http://earlytelevision.org/dumont_ra-103.html
The service info is here:
http://earlytelevision.org/tv_schema...ms_dumont.html
I've restored the 10" Stromberg Carlson incarnation of this set, so I may be able to answer further questions.
Be careful with the tuner BTW. The tuning shaft once you go back inside the tuner is ceramic, and easy to break...It's grease can turn to glue and gum things up. If is is gummed don't force it, take it apart clean the old grease off and relube.