As all you boatanchor weenies and wanna be weenies know, the mystique of the boatanchor is in those glowing beauties we call vacuum tubes. Your cat calls them "a nice place to take a nap". Also, as we guys and gals know, we need a way to find out if these guys are bad or not. Enter the tube tester. Back in the day you could go into just about any shack (or Radio Shack for that matter) and get your suspect tested to confirm yes its bad or "sorry charlie, try again". Well I got a BK707 tester that I got a couple (about 8 ) years ago. I was gonna sell it but now that Im in the boatanchor business, discovered I needed it. Some FB OM out there said I needed to do the calibration on it. Ok looked it over and seemed ok. Put a tube on it and bad...lets try another...bad...wait a second...bad...every tube I have cant be bad...yeah that one was bad too! Then i remembered that someone gave me a Knight tube tester (the one with all the lever switches and the roll chart) anyway thats the only thing I had to even verify that all the tubes were indeed bad (or at least suspect) or that the 707 was FOOBAR.
Got it out, hooked it up to a Variac and slowly dialed up the voltage over 30 minutes till it came back to life without any arky-sparky or electrolytic caps going esplode! I must say its kind of a confusing beast but put a tube in and good....good again...hey this one is good....in all I have only 1 suspect tube but not for sure since the Knight is suspect as well. So now it looks like I might be able to get the Knight back in full calibrated service easier than that 707 so I can progress onward with the boatanchor referbs.
Moral of the story.... If you do not have a WORKING CALIBRATED tube tester. GET ONE because its all about the tubes baby.
PEH!