I need help. I built this a while back, and stopped on it when I couldn't get it to work. I know nothing about transmitters, so I'm clueless where to start looking. It does nothing at all right now.

Well, are you getting voltage out of the transformer and rectifiers?
(6.3VAC to the filaments and ~ballpark~ 140 DC to the plates?)

Is audio reaching pin 6 of the 6AB4?

Is the crystal oscillator oscillatin' through C5 into pin 1 of the 6GY6?

Which schematic did ya work from:

35Z5's:
http://members.cox.net/35z3/6c46gy6062209.jpg

or the instruction guide (PDF):
http://mikeyancey.com/files/Two-Tube%20 ... mitter.pdf

Mike Y
Dallas, Texas

The schematic I go with it is the same as the one in the PDF, with the exception of the power supply. I used different transformers connected with the help of Dave Schmarder.

I haven't checked anything yet.

Your voltage readings would be a good start...

Tom

I'll get them later once it cools down enough to get into my shop. It's 104 here right now.

Finally decided to try to finish this. I quit when I broke the tip off the 6GY6 and couldn't find a spare. Well, as luck would have it, today while I was digging through my tubes looking for one for a radio, I happened to find an NOS Emerson 6GY6.

So I'm back at it again.

So suggestions where I need to begin? IIRC, last I tried it, I couldn't get audio to transmit.

What sort of tools do you have?

If you have a scope (your own, or borrowed), check to see if the crystal oscillator is 'oscillating'. For that matter, make SURE that's wired correctly. Should be (since it's sort of a DIP-16, but with only the corner pins) - MAKE SURE it's wired as in Page 2 of this document:
http://km5z.us/files/Two-Tube%206GY6%20 ... mitter.pdf

Even if you only have a DVM, make sure you're getting 'mostly' the voltages listed here:
http://www.km5z.us/schematics/6C4-6GY6- ... caster.jpg

I.e., something over 150 VDC where it says '200V' - this would depend on your transformer output - and around 6.3 VAC to the filaments, and around 5 VDC to the power pin on the Crystal Oscillator.

Test at least the voltages. Or let us know what kind of test gear you have available (your own or borrowed).

Mike Y

Mike, I have a decent setup of tools. Scope, meters (no DVM though), and a bunch more. I'll try checking voltages in a little while once my movie is over. Todays been very stressful, so I'm taking a smoke break.

"So suggestions where I need to begin? IIRC, last I tried it, I couldn't get audio to transmit."

If the audio portion of the transmitter is the only thing that is not working, it could be nothing more than a tarnished audio input jack (or a broken-incorrect) audio connection to or on the jack).

Did you identify the correct tube pins when wiring up the unit? Do the tubes light up at power up? What are you getting from the DC power supply? Are you getting ~+5VDC to the can crystal power in? Recheck the can crystal, and make sure you have it connected properly. The pin nearest the "F100" is going to be the power in (+5VDC). The pin nearest the "Fox head" is not connected. The pin directly across (from left to right) from the pin nearest the "Fox head" is going to be at 0 VDC, and the pin directly across (from left to right) from the "F100" is going to be the crystal output.

Make sure you are using a suitable antenna with the transmitter. With my transmitters, I'm using a conductor from a 10 ft. piece of Romex that I had left over from a job. Good luck!