Revere S-16 Sound Issue

[Robin Khlop]

I just bought a Revere 16mm projector, and although it runs film just fine there is no sound output. The exciter bulb does not turn on even though I replaced it with one that I know works, and there is no voltage going to the socket. I also noticed that the amplifier does not make a clear sound when I connect it to a working source (as seen in the video). I know very little about tube amps, but I believe that the old capacitors will likely need to be replaced, although I don't know which ones to use. I managed to find a schematic online for what appears to be my model as well, in case someone can get any useful information out of it. Thanks.





Tech Revere S16 diagram.PDF

https://youtu.be/IIt6gwsGSGY (video)

[Maurice Leakey]

Robin
I've never seen such a mess. Normally, resistors and capacitors are mounted on small tag boards and the wiring to them often twisted and neat.
It doesn't seem to be allowed for future easy replacements.
To be quite honest, I should forget it.
It would require a fully-fledged radio engineer to work it all out and to have the ability to acquire any replacement items.
Sorry to be rather blunt.

[Robie Lutsey]

I just finished re-cap'ing a late '40s Victor amp that is point-to-point just like yours. I've seen a number of 40s and earlier radios etc that look just like this.

What I did was analyze the schematic to determine the specs of the capacitors required and then walked my way through the chassis replacing one cap at a time so I don't get confused.

The website here: https://antiqueradio.org/recap.htm is an excellent primer for getting started.

Here are a couple of pictures of my amp before the replacement and one after.

I can confidently assure you it can be done. Your amp looks quite a bit simpler so it should be doable.

Oh, and I got my capacitors from digikey.com. They sell the orange drops for a very reasonable price. They have both 715 and 716 series.

[Maurice Leakey]

Whilst I was a little severe with my previous comment, to do wish Robin every success with a re-wire.
I attach a link to the Instruction Manual when the refurbishment is complete.
Good luck.
Revere 16 (acofs.org.au)
Revere 16 - 16mm sound projector (1948) - YouTube

[Robin Khlop]

Thank you for all the replies; I will try to re-cap my amplifier, and hopefully be able to get the exciter lamp working again.

[Robin Khlop]

It's been a while, but I finally got all of the capacitors replaced. Sadly there is still the issue of the exciter bulb not lighting up, even though I replaced it with a known working one. In addition, when I plugged in another sound source the sound coming out was sort of 'dirty', possibly indicating another issue. Also, I noticed that one of the tubes (the one on the left in the photo) wasn't making any light, even though the sound which came from the source, although a bit rough, was still pretty loud. Any ideas?

[Maurice Leakey]

Robin
I've jusr been looking at the amp's schematic. There is a tube 35C5 which is an oscillator for the exciter lamp.
Is this the tube that is not working?
Vacuum Tube - 35C5, Tetrode, Beam Power | Antique Electronic Supply (tubesandmore.com)

[Robin Khlop]

Yes, that's the broken tube. Since putting the tube into a different socket (of an identical tube) did nothing, I assume all three of them have the same function. I'll try to put in a tested replacement and hopefully that will sort things out.

[Maurice Leakey]

...I assume all three of them have the same function...

No. There are three tubes the same, the 35C5.
Two are the push-pull output tubes, whereas the previously mentioned tube is the oscillator supply to the exciter lamp.