Triplett 630-M

I first heard about the Triplett 630-M in a post from Fred Scoles on the Antique Radio Forum.

I found one locally that has an unbalanced meter movement. It appears to be in calibration when sitting horizontally on the workbench, but the zero changes if I stand it vertically. 

IMG_0538

I haven't torn into it yet, but I did open it up and take a photo of the internals. Perhaps they had to go with a glass-epoxy circuit board to get the leakage currents low enough for the 1 µA (!) meter movement.

Fred was kind enough to send me a manual for the 630-M, which I have scanned and put up for download in my Liberated Manuals section.

© Steve Byan 2011-2016