[Findm-Keepm]

While you are waiting, get inside and replace the 20uF electro with a 22uF 100V cap, and swap out the high-megohm resistors in the grid circuit(s) - there should be a 5.6 Meg, a couple 10 Megs, and maybe one other high resistance IIRC. They greatly affect the accuracy. Dad's had drifted high - I never measured mine - just swapped them out with 2% 1/2W Corning metal film resistors (RCA used to package resistors like NTE, and that's what RCA used, Corning resistors...)


If you have some Deoxit cleaner, spray each socket and "exercise" them by plugging a tube in two or three times. Socket 11, 18 and a few others are/were heavily used - socket 11 being for triode-pentodes (6CG7, 6GH8, 6U8) and 18 for dual triodes (12AT7, 12AU7, 12AX7...). We used socket savers in both 11 and 18 on Dads. I killed his tester trying to test an 8LT8 - it wasn't listed, and I tried a combination that worked, but the tube tested low, so I jacked up the filament voltage to 10V, and cooked the power tranny. Dad had a B&K 747A, so the Sencore wasn't missed much (I think...).