To measure the output of a transformer a good dvm will do the job, just remember the off load voltages will be higher than when its connected and under load.
I've just replaced the transformer on an FT101ZD3 the 900v anode feed had bad HV capacitors which caused it to burn out, if you have power problems i would definitely replace all the psu capacitors and any diodes as well, i disconnected all the outputs from the psu boards and made sure all the output voltages were perfect first and then connected the outputs one at a time and checked them as i went, it took a while to find all the bad HV capacitors in the RF power stages before i connected the final 900v section.
i still have a bit of calibration to do but all the supplies are now good.
Theres a good site that gives a lot of info on the 101EE and other models ?
although the page is mostly about conversion to different valves theres lots of highlighted parts that take you to other pages where theres circuits and other information to be had.
