Postwar American Television
Snaider "Auditorium" Restoration
This projection set was made about 1947. It uses a RCA 5TP4 projection tube, with a lens and flat mirror to project on a translucent screen.
The Cabinet. The cabinet of this set is sheet metal, with a wood front. The sheet metal is in fairly good condition, as the wood front. We will clean and polish the pieces.
The sheet metal around the screen is badly pitted and rusted. We will remove the rust and repaint it.
In disassembling the set we broke the front screen. A new one has been made.
The Chassis. There are four chassis in this set. One contains the power supplies. The Audio/Video chassis contains the RF amplifiers, video amplifier, and audio circuits. Another contains the sync separator, sweep circuits, and high voltage (EHT) supply for the CRT. The final chassis is for mounting the CRT and lens. Each has been cleaned in a mild detergent.
Power Supply Chassis. (pictures) The power supply chassis is somewhat rusted. After replacing the fuse, the power supply worked perfectly.
Audio/Video Chassis. (pictures) This chassis is in good condition. After replacing all the paper capacitors, the chassis worked.
Sweep/High Voltage Chassis. (pictures) This chassis is in good condition. Several electrolytic capacitors were bad, and had to be replaced. This chassis develops about 27 kilovolts for the projection tube using 3 - 1B3s as a voltage tripler. A voltage divider creates the 5 kv focus voltage. After replacing all the capacitors, this chassis worked.
CRT Chassis. (pictures) This chassis is in good condition. A f1.9 lens is used to focus the CRT image on the screen. This arrangement results in a dimmer picture than the system used in other projection sets, such as the GE 901 and the Bell and Howell protoype we have. They use a concave reflector to focus the image.
The set now works, and after the cabinet painting is complete, we will reassemble it.