Testing functionality of output transformer-Is it DOA?

[Cygnus X1]

On testing the output transformer...since I don't have a filament transformer I connected a portable radio to the
OT primary.
From the headphone jack.
Connected speaker to the correct jack.

It pushes the signal, although it is weak.
I guess that tells me the OT is good?
Or does this not mean anything at all?

I must emphasize that the amp was unplugged and discharged when doing this, the OT was connected and the tubes out of the amp.