How to test bad Output transformer.

[JR]

Got an amp 3-12ax7s and 2-el34s. When I probe the
plate pin of one of the OT tubes I get 450 volts and on the second tube I
get nothing. Can it be something besides the OT transformer. BTW its a huge
Hammond Transformer. The OT is out of the amp now any quick way to test it
with a multimeter.
Please use layman descriptions on trouble shooting.

[Bdigel]

There are two windings in your transformer, the primary connected to the power
tubes and the secondary connected to the speaker. The ends of the primary go
to your output tube plates, and the center tap (middle) is connected to high
voltage from the power supply. Using your ohmmeter, measure from each end of
the primary to the center tap. You may find that one half of the primary is
open (infinite resistance). Other than a bad connection between the
transformer and the tube pin, an open primary winding half is a likely cause of
the symptom you describe. Check the schematic for your amp to see if what I've
said makes sense to you.

Bill

Bill
Bill Digel
Wilmington, Delaware, USA