User's Manual

tube contains excessive gas. When testing a multisection tube,

make the gas test on an amplifier section; it does not apply to diode

sections or to rectifiers.

a. Perform the operations in paragraphs 15 and 16.

b. Operate the FUNCTION switch to the TEST position.

c. Operate the PLATE-SCREEN RANGE switch to the posi-

tion specified on the tube test data roll chart.

Warning: Do not touch the top cap of a tube under test after

plate voltage has been applied.

d. Adjust the PLATE and SCREEN fine controls until the

PLATE and SCREEN VOLTS meters indicate the exact voltages

specified on the tube test data roll chart. Red calibration marks

on the scales of both meters facilitate this adjustment.

e. Operate the BIAS RANGE switch to the voltage or position

specified on the tube test data roll chart.

f. Adjust the BIAS fine control until the GRID BIAS VOLTS

meter indicates the specified voltage.

g. Set the quality SHUNT control to the number given on the

tube test data roll chart, and adjust the PERCENT QUALITY

meter to zero (par. 17).

h. Operate the GM-SIGNAL RANGE switch to the position

specified for the quality test.

i. Adjust the SIGNAL-V.R. fine control until the pointer of

the SIGNAL VOLTS meter is on the red line.

j. Depress the PRESS TO TEST P4 switch to its locking posi-

tion.

k. Depress and hold down the PRESS TO TEST P6 switch.

Depressing the P6 switch may cause the PERCENT QUALITY

meter pointer to move upward or downward on the scale. If the

pointer moves more than three scale divisions in either direction,

the tube contains too much gas for satisfactory operation.

Note. Some tubes develop gas after they have been in operation for a

period of time. When this is suspected to be the case, let the tube remain

under test with operating potentials applied for several minutes before

making the gas test.

l. When the test is completed, set the ON-OFF switch to the

OFF position, remove the tube under test from the test socket,

and return all switches and controls to their safety positions

(par. 15d).

23. Emission Test

Use the following procedure to test the emission (EM) of recti-

fier tubes, diode detectors, and multielement tubes.