B-HEATERS
I-Connect the heater or filament of the tube
to the Heater Supply jacks.
II-Duplicate the connections from the heater of
lhe tube and connect to the Heater Meter
jacks.
C-SUPPRESSOR
I-Connect suppressor to Suppressor Grid jack
except for the following two conditions.
(a) When other tube elements require a pos-
itive voltage from the Suppressor Grid
jack follow steps II or III outlined below.
(b) When Self Bias Resistance control is set
to or any value above zero ohms, step
III outlined below must be followed.
II-Connect suppressor of tube to any of the
three Cathode jacks in the bottom row when
the Self Bias Resistance control is set to
"Fixed Bias" or zero ohms.
III-Connect suppressor of tube to the second or
third Cathode jack when the Self Bias Resist-
ance control to set to any value above zero
ohms.
4. Rotate Short Test
-Meter Reading switch to
"Short Test" position.
5. Select the required heater voltage by setting the
Heater Voltage Selector switch.
6. Insert tube in a socket corresponding to the pin
arrangement of the tube to be checked.
7. Place the Heater Supply toggle in the "On"
position. For those instruments connected for 230
volt line service see "Note" under paragraph headed
"HEATER SUPPLY TOGGLE SWITCH", on page 6.
8. Rotate Heater Voltage Adjuster to correct heater
voltage indicated on Heater Voltage meter.
. 9. Rotate Element Short Test switch through its six
positions, stopping at each position to tap the tube.
10. A lighted neon lamp indicates a short in the
tube and no further tests should be conducted. A
lighted neon lamp on Position (1) indicates heater to
cathode leakage.
11. From time to time check neon lamp by placing
Lamp Test toggle in the upper position.
12. Set the Self Bias Resistance control to "Fixed
Bias" or zero ohms position. Note: If manufacturer's
rating specifically calls for self bias, set the control
to the proper value.
13. Rotate the Control Grid, Suppressor, Screen
and Plate adjusters to the extreme counter-clockwise
position.
14. Index Short Test -Meter Reading switch to
"Meter Reading" position.
IS. Place Plate Supply toggle switch in the "On"
position.
.
16. Index Gill Factor switch to the "XIO" position.
The "Xl" position may be used for subminiature
tubes or low bias high mu tubes.
17. Index
Gill Range switch to .a range consistent
with the expected mutual conductance. This is the
value listed by the manufacturer.
18. Index Element Current switch located below
the
Gill Factor toggle switch to the "Plate" position.
19. Index Element Current Range switch located
below the Element Current meter to a position higher
than the expected plate current specified by manu-
facturer.
20. Rotate the Control Grid VoItage Adjuster un-
til the Control Grid Voltmeter indicates the value
specified by manufacturer. If over 10 volts, index
Control Grid switch to "50 Volts" position. Rotate to
extreme counter-clockwise position if Self Bias Re-
sistance control is set to any position other than
"Fixed Bias" or zero ohms.
21. Index the Element Voltage switch located un-
der the Element Voltage meter to the "Plate" position.
22. Advance the Plate Voltage Adjuster until the
Element Voltage meter indicates the plate potential
specified by manufacturer. If over 150 volts, index
Element Voltage Range switch to "300" volts position.
23. Index Element Voltage switch to "Screen" posi-
tion.
24. Advance Screen Grid Voltage Adjuster until
the Element Voltage meter indicates. the screen po-
tential specified by manufacturer. If over 150 volts,
index Element Voltage Range switch to "300" volts
position. Important Note: To prevent excessive screen
dissipation keep the plate potential the same as or
higher than the screen potential.
25. Recheck the plate, screen and control grid
voltages.
26. Plate, screen, suppressor or cathode currents
can be readily checked by rotating the Element
Current switch through its four positions noting the
current on the Element Current meter. It may be
necessary in doing this to change range on the Ele-
ment Current meter by rotating the Element Current
Range switch to one of the other positions.
27. If the tube is a filiamentary type, place the
Gill Factor toggle switch to the "x 1" position and
rotate the Hum Control to give minimum reading on
the fan-shaped Micromhos meter. Note: Serious errors
in mutual conductance readings can be expected if
this operation is not performed carefully on filament
types.
28. Pull the Microamperes toggle switch to the
"IS" position. Read microampere grid current di-
rectly on 15 scale. Refer to "Grid Current" under
Helpful Suggestions In Tube Testing on page 10.
-7-
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