New guy here, scratching my head with radio problem.

Bob: When you check the audio part by touching the volume control, you touch it with your finger, perhaps while holding a probe or screwdriver.

You must NEVER, NEVER touch the chassis with the other hand while working. That's inviting a serious shock right across your heart. In the Navy we were taught to keep the idle hand in your pocket. Unmilitary, but smart!

Solution from the resident Electrical Engineer (ME! hehe)

Quick Fault-finding Process:
1. Check the voltages on all the filament pins on the tubes.
2. Filament voltages good? Check the HV on respective plate pins on all tubes (there's a nice look-up chart on the second page of the schematic you've referenced)

3. HV also good? Connect your oscilloscope to the output of the first audio stage (the anode of 6SQ7). If you have a nice audio waveform bouncing all over the place on your screen (you need to tune your radio up and down until you see one), you know that your problem resides in the final Output stage (6K6GT). Now you know where to look for the problem.

4. No nice bouncy audio signal? Connect your Oscilloscope to the output of the IF stages (6SA7 and back), and make sure you're getting a nice AM envelope (you're going to have to tune up and down the dial again to find a radio station).

5. No signals present? Check tuning caps aren't shorted (all the funny little tuning caps on the gangs, on the chassis etc...) You can do this with a continuity tester.

I can't get into too much detail here, but you're going to have to repair your local oscillator.

DISCLAIMER: I'm not sure of the level of your electronic expertise, the processes I've mentioned above may cause damage to your equipment if not carried out correctly.

As an additional note, I'm not sure the condition of your radio's power supply, so make sure to isolate your oscilloscope's supply with an isolation transformer. If not, you could still perform your tests by not connecting the Probe's ground pin to any part of the radio. Also make sure to use voltage-divider probes, and set them to the highest value when performing initial tests. An isolation capacitor in series with the test probe may be necessary in some tests as well.

let me know how goes the repairs!

If you touch it with your finger, just use your index finger, and not touching any other part of the radio at the same time, you should get a loud 60 cycle hum or buzz. this would indicate your audio section is working. If no noise then the audio section is needing troubleshooting.

Start testing resistors and test ALL of them, not just the ones that "look bad". I've had many resistors that were open that had no visual flaws to make me suspect them. If the radio has been compleatly re capped and all of the tubes test good i would suspect a bad (probably open) resistor and i would think that it is in the output section of the radio.I had a RCA that had a problem that sounds the same as yours and i fought with that radio off and on for 2 years before i decided to do as everyone had been telling me and test the resistors and shure enough there was a bad one on the grid of the 6k6 output tube.

Nick