[Ron Ramirez]

The original 32-7997 transformer has the following specifications:

Primary impedance 12,000 ohms; secondary 5 ohms; 10 watts.

You can use a Hammond HX-125D as a replacement, available from Radio Daze or Antique Electronic Supply.

Edit: You won't find a new transformer that has the feedback tap in the secondary which the original had. But that can be worked around; we can tell you how when you get your new transformer.