New to antique radios, in particular the above battery tubes. To check voltage (1.4) across pins 1 and 8, can someone explain the grid connection? Should I be measuring ground from chasis?

Pins #1 and #8 are filament of tubes starting with 1Lxx. You should be able to measure around 1.4 volts between these pins in when a radio is in operation.

Grid #1 is pin #6 on most of these tubes. You can get specific information on tubes here:

http://tdsl.duncanamps.com/tubesearch.php

When checking grid voltage of a tube it's measured between grid and filament. You can't be sure the chassis is connected to the filament so not a good place to use as reference.

Some schematics show voltage that are measured from chassis.

Norm

:Hello,
:
:New to antique radios, in particular the above battery tubes. To check voltage (1.4) across pins 1 and 8, can someone explain the grid connection? Should I be measuring ground from chasis?