5B3 Deluxe help with transformer identification

[tubesinside]

Help from my Fender experts.
I have a 1952 Tweed deluxe 5B3 (I think) in for service. Unfortunately it's been 'repaired' already and all of the coupling caps have been replaced with orange drops.
The amp only outputs about 5 watts into test load.
Output tubes are perfect, driver tube is fine. Voltages as follows:

AC in 117 V AC
AC on 5Y3 294
DC 1 328
DC 2 260
DC3 240.

I suspect that the transformer is not the original and not enough B+
Markings on the transformer show two numbers:
961199-2-5 and 352545

Pictures attached.
Does my traffo look big in this?

[Firestorm]

Wow, that is a seriously big chunk of iron. No, it is not the original PT, but the voltages aren't way off; the schematic I have shows B+1=350, B+2=280, B+3=250. Output should be about 10W. It doesn't seem that the voltage difference would account for 5W output. Maybe something else going on. You could try a 5AR4 and see what higher B+ gets you, but there is likely another issue.

[tubesinside]

Thanks Firestorm. Ill try that tomorrow.