If the fuse is Ok, then you need to check the voltages on the transformer with it turned on and the tubes in. Be very careful, these voltages can really hurt you.
Edited to correct terminals.
Measure Voltage, AC, from transformer terminal 1 to transformer terminal 2. It should be 120V +/- 15%.
Measure Voltage, AC, from transformer terminal 4 to transformer terminal 5. It should be 6.3V AC +/- 15%.
Measure Voltage, AC, from transformer terminal 6 to transformer terminal 7. It should be 150V +/- 15%.
Measure Voltage, AC, from transformer terminal 9 to transformer terminal 10. It should be 150V +/- 15%.
Post back any that are out of spec.