[Hallicrafters] Single Tuning Knob 1930s Sky Buddy

[KA6UUP]

Guys, I need a little help.
I have a 1930s vintage Sky Buddy with only one tuning knob.
The fiducial is projected on the back of the "bandspread" dial
It is NOT the 5T. I have never found a schematic which fit this radio
and wonder if anyone knows anything about it?
Pictures are here: 
http://s943.photobucket.com/albums/ad271/ka6uup/Hallicrafters Sky Buddy/
Tnx es 73,
Chuck KA6UUP