Thanks @Jean-Paul. What do you mean by "metered" variac. I have a variac. Do you just mean put a meter on it to more carefully calibrate the suggested voltage? Or, if I read-between the lines, where you say to observe the "mains current", are you suggesting that I put a DMM inline in ammeter mode between the variac and the 577 to monitor current? And if so, what am I looking for at the suggested voltage stops (30, 60, 90, 120)? Thanks.
