[Mondial]

Here is the service info for your radio:

http://www.nostalgiaair.org/PagesByModel...013586.pdf

There is a chart which gives all the voltage readings for the tube socket pins when the radio is operating properly. Compare these readings to yours to try and localize the problem.

As Codefox said, a bad resistor could cause your symptoms. Voltage checks should point you in the right direction. I would check around the 7F8 tube first.