From schematics the norm of that era 110 v is what is printed on them.

High tapping is a band aid fix Imho for a much bigger problem from what your describing.

I would open up the Breaker box / fuse panel and check the voltage direct from there, from that you can determine whether its a power company issue ? ,( transformer or service feed wiring to the meter box ) or is it a ( resistance problem within the service panel ) down line within the buildings wiring reducing it ?
Electricity is not much unlike a pickup bed , putting too much weight in it will reduce its power to get the same results to achieve that a lighter load would require , basically the more weight you have you must increase the horsepower to get back what was lost.
Bottom line the reduced voltage you have in the establishment will not hurt the machine but the playing performance will suffer.

Doing an electrical audit will reveal the weak link.
Good luck....