Yesterday I started up my 803A just to circulate some oil and I noticed that the voltage was reading 220v and I had just ran it a month ago and it was set at 240v. I attempted to adjust the knob and could only get it to 230v before hitting the limit of the knob. After a few attemps at adjusting the voltage regulators pot screw, I was able to get it back to 240v but now I am concerned that the voltage regulator is defective. Are these things just quirky?