I agree with what has been said here. Willie68 has a good suggestion and as he said it cannot hurt. Long term it is best to replace the tubes with leds. These machine were never designed to live this long life that they have found. I did this with a Bally Playboy restoration that I did and to the naked eye you really cannot tell. The bonus is that you can then disable the high voltage section of the power supply which over the years does become problematic. Just my .02