Here's a .pdf manual
http://www.fender.com/support/manuals/pdfs/manuals_elec/guitarpdf/Bronco.pdf
Year: 1967-1975
Model: Bronco
Circuit: AB764
Config: Combo
Control Panel: Silver forward facing w/ red labels
Front Conrol Layout: In, In, Vol, Treb, Bass, Speed, Intensity - Power Sw, Pilot Lamp
Knobs: Black skirted w/ chrome center, numbered 1 - 10
Cabinet: 14½" x 17" x 7¼" (36.8 x 43.2 x 18.4 cm)
Cab Covering: Black Tolex
Cab Hardware: Black Strap handle, 3½" chassis straps, glides
Grille: Blue sparkle grille cloth w/ aluminum frame (68-69), w/o aluminum frame (70-75)
Logo: Grille mounted, raised, chrome & black script "Fender" w/ tail (68-69) or w/o tail(70-75)
Weight: 20 lbs. (9.1 Kg)
Speakers/Load: 1 x 8"/4 ohms
Speaker Model: Oxford 8EV
Effects: Tremolo
Output: 6 Watts
Preamp: 12AX7A
Power: 6V6GTA
Bias:Cathode Bias
Rectifier:5Y3GT
Other:
Tremolo: 12AX7A (bias vary)
Comments: The circuit number on the schematic seems very early for an amp released in 1967. This is most likely due to the fact that the Bronco and the Vibro Champ are nearly identical.