Avionics Bending: Engine Oil Quantity Indicator

L-1011 Engine Oil Quantity

The Engine Oil Quantity used on the Lockheed L-1011 is a General Electric 8DJ173 LWD1 and is a relatively simple instrument. It takes 115V 400Hz power. The instrument has a BITE test button on the lower left front. The test switch drives the indicator needle to 10.5 Quart. You can see operation of the instrument in the short demonstration video below.

On the real aircraft the instrument acts as the power source for the oil quantity probe. The instrument outputs 6.5VDC which can then be run through a digital 10K potentiometer to simulate the oil level probe. 

Below is the schematic and pinout for the Instrument from the L-1011 Training manual:

Engine Oil Quantity - Pinout and Schematic