Anyone familiar with 16mm projectors?

[Ken1]

Hi, I have an RCA model 400 16mm projector. Everything works except the sound. The sound bulb does not light up and the 4 volts that powers it is missing. Following the wiring back to the chassis, the wires connects to a component that looks like an adjustable coil or transformer that was commonly seen in tv's of the 50's. There are 5 wires coming out of this transformer. It has 2 windings; the winding that connects to the bulb has 3 leads. The other winding with 2 leads feeds B+ to a 6V6GT tube. B+ is present on this winding. The third lead from the bulb winding connects to the same tube through a parallel combination of a 3300pf disc capacitor and a 47K 1/2 watt resistor. Any suggestions?

[Lenp]

Ken

The exciter lamp is driven by an oscillator. Here is the link for drawings. http://www.acofs.org.au/part_5_files/RC ... iagram.PDF

Hope this helps!
Len

[Ken1]

Hi, Thanks for your reply. The information was very helpful. The problem was caused by a shorted .01uf 400V tubular capacitor connected from the screen of the 6V6GT to ground.

[dacflyer]

neet, i never knew that exciter lamps were oscillater driven.
i always thought they were just lit by low voltage. learn something new each time

[Bob Scott]

neet, i never knew that exciter lamps were oscillater driven.
i always thought they were just lit by low voltage. learn something new each time

Some old Sony industrial Betamax VCRs had a tape sensor IR LED driven by a 6KHz oscillator. The detector circuit was set up to detect only the 6 KHz signal. It was done this way so that regular ambient room lighting would not affect the VCR operation.

There is your trivia for the day.

[dacflyer]

interesting.. sort of the same deal as for IR remotes...
i just happen to have some BETA tapes also..lol and sony players.