[Chad Hauris]

What I would do is...
1. remove the plate cap lead from the horizontal output tube. Hook the disconnected lead up with an alligator clip lead to the voltmeter and measure the voltage (since the HO tube is not in the circuit you won't generate HV AC)
You should read about the B+ voltage. With this you can see if supply voltage is getting to the HO tube. This will also check if the damper is working because the B+ has to go through the damper before it gets to the flyback.

2. check negative grid voltage at HO tube grid with the flyback connected back in the circuit. Should likely be more than -30 volts. If the neg. grid voltage is low there is likely low drive from the oscillator.

Sometimes the audio detector stage runs off the boost voltage and if the HO Circuit isn't working right this can cause no audio.

Another possiblilty is if there is low grid drive to the HO tube it got destroyed from the overload. Had this happen on an RCA CTC-16...once I fixed the oscillator circuit and replaced the HO tube it was fine. (there was a lack of plate voltage to the oscillator)