Aircraft Instruments Technical Instructions, Air Corps Technical School, 1939 C-130 Measures 4 inches diameter and

Measures 4 inches diameter and ~11 inches deep

Weston model 1534

but the content pertains to aircraft instruments common in the early 1940's

See photo of Tony instrument panel showing the location of this compass from a book by WWII Japanese Aircraft researcher Robert Mikesh

unscrew the collar (I) and pull the lamp support assembly straight out

Aircraft Instruments Technical Instructions, Air Corps Technical School, 1939 C-130 Measures 4 inches diameter andHere is a pre WWII era Technical Instruction reference manual for students of the Air Corps Technical School, published in October 1939, for use in training aircraft instrument technicians of the US Army Air Corps. This 258 page, 8. 5 by 11 inch technical manual covers all of the most commonly used instruments used in aircraft of the era, including pressure, temperature, and quantity gauges, compasses, turn, climb, and airspeed indicators, gyro