I have no experience with tube gear. I have the schematics and a voltmeter/ohmmeter. Looking at the schematics, it shows pin 4 is "12.6V to heaters" and pin 6 is ground. I connected my voltmeter to those pins and it shows .72 volts. So my power supply is toast?
Maybe. More likely there's a bad connection or a short-circuit somewhere.
Here's how I would test it:
First, Unplug the power supply from the mains outlet and make sure all the filter caps are discharged.
Second, Unplug the rig-to-power-supply cable at the power supply.
Third, Put a jumper from Pin 1 to Pin 2 on the power suppy Jones socket. (Note: MAKE SURE you have the right pins!) This jups out the power switch, so the power supply will be ON as soon as you plug it in.
Fourth, Connect the voltmeter to read AC voltage from the heater secondary (12.6 volts). I'd do this inside the power supply, because a bad ground or connection could be the problem.
Fifth, Plug in the power supply. It should turn on and the meter should read 12.6 volts or a little more.
Sixth, unplug the power supply, make sure all power supply capacitors are discharged, and remove the voltmeter and temporary jumper.
It is highly unlikely that the power transformer is bad. You'd smell it, and it would probably blow the fuse in the power supply.
It is much more likely that there is a bad connection somewhere in the heater circuit. The transformer must supply 12.6 volts at 5.5 amps, and a bad solder joint, loose ground lug, loose contact or other problem could easily cause the problem.
Was the rig working, and then it failed? Or did you just get it? What's the history?
73 de Jim, N2EY