OK, but that meter reading is "open", far from zero ohms. CONNECT THE TWO PROBES TO SEE A ZERO READING.
And the transformer certainly looks like the paper can be opened up to find that internal fuse. Or is that a copper band around the windings? And while the amp does look fairly well made, that fuse buried inside the transformer places a serious doubt about the quality. I have only seen that done in lower quality items, where the transformer quality, or capabilities are marginal. And you would never ever see that in equipment designed to be durable and rugged.
One momentary line voltage spike will pop the fuse and the show is over.
So now it is time to either replace the transformer or remove it and carefully investigate. My money is on that fuse being open.
Now I question the validity of the meter readings , because an open circuit is not likely to have any inductance.
My bad yes it is open not zero.
Standard practice to connect the two probes when using this meter on 200 Ohm range. it usually settles at about 400 t0 500 milli Ohms.
Yes it is a copper band.
I agree , the the readings are strange. As you said " an open circuit is not likely to have any inductance"
My suggestion is maybe micro Ohms-----i'll need a kelvin bridge for that.
As for the momentary line voltage spike , i have no way of knowing what the owner did prior to receiving this blessing.
The transformer is no longer available according to Pioneer spare parts------it is 30+ years old.
What do you think of my micro Ohms theory?
Thanks for your inputs.