User's Manual

ated for the PLATE SELECTORS switch on the tube test data
roll chart.
e. Set the GM-SIGNAL RANGE switch to the F position.
f. Adjust the SCREEN fine control until the voltage specified
on the tube test data roll chart for the PLATE meter is indicated
on the SCREEN VOLTS meter.
Note. It may be necessary to set the PLATE-SCREEN RANGE switch to
a new setting, moving the switch in a counterclockwise direction, so that the
SCREEN VOLTS meter can indicate the voltage specified for the PLATE
meter.
g. Adjust all other fine controls as required on the tube test
data roll chart for the tube under test.
h. Turn the SIGNAL-V.R. fine control to its maximum counter-
clockwise position.
i. Set the FUNCTION switch to the VR position.
j. Set the quality SHUNT control to 0.
k. Depress the PRESS TO TEST P5 switch. Be sure the proper
voltages for the tube being tested appear on all other meters.
Note the reading on the 0- to 50-milliampere (ma) scale on the
PLATE meter.
l. Release the PRESS TO TEST P5 switch.
m. When the test is completed, set the ON-OFF power switch
to the OFF position, remove the tube under test from the test
socket, and return all switches and controls to their safety posi-
tions (par. 15d).
26. Thyratron Test
Use the following procedure to determine the firing potential
of thyratron (TH) tubes. Thyratrons are also called gas triodes
or grid glow tubes. The firing potential may be defined as the grid
voltage at which the tube begins to conduct.
a. Perform the operations indicated in paragraphs 15 and 18.
b. Set the FUNCTION switch to the VR position.
c. Set the PLATE-SCREEN RANGE switch to the position
specified on the tube test data roll chart.
d. Set the quality SHUNT control to the number specified on
the tube test data roll chart.
e. Set the SIGNAL-V.R. fine control to its extreme clockwise
(maximum) position.
f. Depress and hold down the PRESS TO TEST P5 switch.
Note the current through the tube as indicated on the PLATE
meter, and note the reading of the PERCENT QUALITY meter.
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