Film-Tech Forum ARCHIVE: No sound to FM transmitter

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Posted by Richard Greco (Member # 2032) on 05-11-2005, 10:53 PM:

Ok, I got a call tonight that Screen 2 was down with no sound. I got there and checked EVERYTHING. There was power, I used another amp and no difference, I used a different reciever to see if sound was coming from the machine...There was. However this amp had no output for a RCA cable. Going on that information, I hooked up an AM/FM radio using the RCA output cable to the transmitter and I still didn't hear anything over the air, there was no signel on the transmitter.

I'm stumped, since there IS signal from the projector I know it isn't on that side, but I'm not sure if the amp is dead. Since I hooked up the output wire to that AM/FM radio and no sound was there either, I'm thinking it is from the output wire to the transmitter is where our problem is. Any ideas?

Posted by Monte L Fullmer (Member # 2797) on 05-11-2005, 11:12 PM:

Checked leads, or changed leads from the amplifier to transitter? could be an "open" somewhere in those leads, or transmitter took a solid dump.

For you "condemned" the projector and amplifier as being operatable, yet the transmitter's output is dead, thus is it the wiring or transmitter be your problem?

No spare transmitter there, or did you trade out transmitters from one screen to this one to see if the problem follows?

That's the usual first step-is to trade something for something and see if the problem follows the trade.

- Monte

Posted by Barry Floyd (Member # 385) on 05-11-2005, 11:25 PM:

Amp?? I assume you have field speakers? Do you go thru any type of processor?

Is your transmitter giving a clear dead silent signal on the channel it supposed to transmit on? At my theatre, when I switch on the sound rack, the transmitter powers up, then takes a couple of seconds before the signal "locks", As soon as it locks, it just put out clear silence.

If your transmitter is working properly, I'd trace the problem back to your LED reader. If it's got power, go to the next step in the chain...your processor.

If your transmitter IS working and your LED reader is putting out a signal, you can do a quick and dirty direct wire from the LED output to the transmitter.

You said SCREEN 2... and your in Florida. Is your theatre either the Silver Moon or Fun Lan? I've been thru both projection booths there.

Jack O from the Rodeo drive-in or Ken Layton might be of help on this topic.

Posted by Ken Layton (Member # 133) on 05-12-2005, 09:44 AM:

Have you tried feeding a signal from some other source such as a cd player, tape deck, audio generator, etc. into the input of the radio transmitter? If you now get a signal doing that then your amplifier or it's cable to the transmitter is bad.

Posted by Richard Greco (Member # 2032) on 05-13-2005, 11:36 AM:

Well, It was the output wire to the transmitter. It lost it's connection to the preamp. Problem solved and back on screen yesterday.