Newbie's First Questions RCA TS 721 Restoration

[Chris K]

Originally Posted by Penthode

Did you follow my instructions to set the local oscillator? What did you find?

To facilitate injecting video directly you will need to build a 75 ohm interface. It could be connected to the grid of the first video input stage. Then you could inject audio to the volume control. It will take a bit of fiddling as you have to ensure the video polarity is correct.

It appears you were very close connecting by the antenna. What happened?

I need to go on ebay and get a radio with a signal strength meter. I thought I had one but I didn't. Couldn't work on the oscillator just yet. I did get an RF modulator that injects excellent, clear video in my Zenith B&W TV into the antenna from my computer's HDMI output and I fed that into the antenna on the RCA and I got a decent picture...a little snowy but decent...but still no sound.

Could I go into the 12AU7 grid with a composite video signal? The modulator I got has RCA video and sound outputs and I can mount 2 RCA female connectors on the back of the 721 chassis and run the signals to the volume pot and the video amp grid. But if this TV has some funky video system, this might not work.

[Penthode]

You don't need a fancy radio. Don't you have an FM radio kicking about? What kind of FM radio do you have?

[Chris K]

Originally Posted by Penthode

You don't need a fancy radio. Don't you have an FM radio kicking about? What kind of FM radio do you have?

I have an old channel master super fringe FM radio

[Penthode]

Originally Posted by Chris K

I have an old channel master super fringe FM radio

Tube model? That should work in a pinch. What does it look like? Model number?

It doesn't have to be fancy. You may hear the silent carrier as you tune to it.

Right now we a just fishing for the local oscillator. Use as your reference the radio stations I indicated and the oscillator should be right next to the 92.9 KHz low power station in Philly. It is probably well off from that. Just connect the TV antenna terminal with the set on channel 4 directly to the radio antenna and tune until you hear what would be like a silent radio station.