Just my two cents...
Back when there were mfg facilities here and I had tools, there were some plant maintenance guys that would 'fix' things, instead of calling the plant EC. Fuses were replaced with 'that's all we had', forget the ratings. "Why use the time delay ones" "Isn't 15 better then 2", etc. (No reflections meant to you Potseal)
The second tap for another control circuit? You didn't mention if it looked like it was done by 'qualified person'.
As to the load killing the control transformer, IMHO the 'old' ones sure could take a lot of excess for a long time. In a printing plant that I worked in for 20+ years, some of there original DC equipment was over 50 years old & still functioning. Some replacement contacts were 'plant made' in the machine shop, as Cuttler Hammer laughed when I tried to order replacements.
Bottom line IMHO, it was 'time' for the old transformer to rest in peace.
