Admiral console model Y4941A trouble shooting

I have an Admiral Stereo Console model Y4941A chassis no. 9P1.

All parts worked until recently. Now, after turning the unit on and running for two minutes, the volume fades out completely and I have no sound to the left speakers. Neither the volume nor the audio returns by switching it off and on.

I've replaced tubes and still the same issue.

Can someone give me repair advice?

I live in a small town and have tried to locate a local repair person, but I've had no success.

Any assistance would be greatly appreciated.

Thanks
Nola

Pictures please. No fun without pics. While a tube might have been the culprit I would first test them before replacing them. How old are the capacitors? Is there any hum? One check you could make is to lift the tone arm and touch each one of the wires that connect to the cartridge. If you hear a hum from that channel left or right suspect your cartridge. If no hum then on to the amp.

The grid leak resistor of one of the tubes is open. As the set runs, a charge builds up on the grid, and the sound stops.

This resistor is usually 470 K or 1 M ohms connected between the control grid of the tube and common. It drains accumulated charge off the grid,