Amp: 65 PRRI with new tubes and reverb cable. Symptoms: random static noise exacerbated by tapping anywhere on the amp - even with PI pulled. No flashing on any tubes accompanying the noise. Possible clue: added 1M resistor to PI Grid the day before. This is my first time playing it since. Not in the mood for this! The solder job on the 1M grid stopper is clean, as I'm a builder with experience. Just no mental capacity left due to new dad sleep deprivation. Halp!