Zero Adjustment of PERCENT QUALITY Meter

RANGE switch to the next higher position, and then adjust the

c o n t r o l until the correct voltage is indicated on the meter.

i. I f t h e l i n e v o l t a g e i s h i g h a n d i t i s n o t p o s s i b l e

to adjust

the FILAMENT fine control to indicate the specified

voltage,

turn the FILAMENT RANGE switch to the next lower

position,

and then adjust the control until the correct voltage is

indicated

on the meter.

17. Zero Adjustment of PERCENT QUALITY Meter

When the procedures in paragraph 16 have been completed,

adjust the PERCENT QUALITY meter to zero. This adjustment

should be made before testing any tube for transconductance

(GM) as follows:

a. Turn the GM-SIGNAL RANGE

switch to the F position.

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

t i o n . Reset the controls to give the exact meter readings specified

i n the METER SETTING columns of the tube test data roll chart.

c. A d j u s t t h e G M C E N T E R I N G c o n t r o l u n t i l t h e p o i n t e r o f t h e

PERCENT QUALITY meter is set exactly to zero on the scale.

d. Release the P4 switch.

1 8 . Short Test

a. P e r f o r m t h e o p e r a t i o n s d e s c r i b e d i n p a r a g r a p h s 1 5 a n d 1 6 .

b. For the TV-2/U, aline the dot on the PLATE fine control with

the dot on the panel. For TV2A/U and TV2B/U, aline the

P L A T E fine control pointer-type knob with the line index marking

o n the panel. This assures that the correct voltage will be applied

to the short test circuit.

c. T u r n t h e S H O R T T E S T s w i t c h s l o w l y f r o m t h e O P E R .

p o s i t i o n to V, W, X, Y, and Z, and back to OPER.; at the same

time, tap the tube with a finger and watch the FIL. CONT. SHORT

indicator lamp.

Caution: Do not tap the tubes listed below when testing for

short-circuited elements. Tapping may damage the tube.

1LH4

1A5GT

1LN5

1A7GT

1P5GT

1C5GT

1Q5QT

1G4GT

1S4

1G6GT

1S5

1H5GT

1L4

1T4

1T5GT

1LA4

1U4

1LA6

1U5

1LB4

1LD5

3A4

1LE3

3A5