[Johnson] Viking 2 Modulation Transformer

[w6we]

Gents, How can I determine is the modulation transformer is still in good condition? My problem is I cannot modulate to the suggested 250 Ma , getting no more than 125Ma. I seem to have all the gain I need in the preamp stages. When acquired the audio mods from ER had been installed but not the regulated screen supply or the fixed bias on the 807's. All- in-All, it works but just barely. need to reduce the final input to 80w or so to fully modulate with mic gain fully open. 
Any and all input will be appreciated.( This is my first input to the forum)  
Mike W6WE AMI #1526