Thyratron Test

ated for the PLATE SELECTORS switch on the tube test data

roll chart.

e. S e t t h e G M - S I G N A L R A N G E s w i t c h t o t h e F p o s i t i o n .

f. A d j u s t t h e S C R E E N f i n e c o n t r o l u n t i l t h e v o l t a g e s p e c i f i e d

o n the tube test data roll chart for the PLATE meter is indicated

o n 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-

c l o c k w i s e position.

i. S e t t h e F U N C T I O N s w i t c h t o t h e V R p o s i t i o n .

j. S e t t h e q u a l i t y S H U N T c o n t r o l t o 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. R e l e a s e t h e P R E S S T O T E S T P 5 s w i t c h .

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

o r grid glow tubes. The firing potential may be defined as the grid

v o l t a g e at which the tube begins to conduct.

a. P e r f o r m t h e o p e r a t i o n s i n d i c a t e d i n p a r a g r a p h s 1 5 a n d 1 8 .

b. Set the FUNCTION switch to the VR position.

c. S e t t h e P L A T E - S C R E E N R A N G E s w i t c h t o t h e p o s i t i o n

s p e c i f i e d on the tube test data roll chart.

d. S e t t h e q u a l i t y S H U N T c o n t r o l t o t h e n u m b e r s p e c i f i e d o n

the tube test data roll chart.

e. S e t t h e S I G N A L - V . R . f i n e c o n t r o l t o i t s e x t r e m e c l o c k w i s e

(maximum) position.

f. D e p r e s s a n d h o l d d o w n t h e P R E S S T O T E S T P 5 s w i t c h .

Note the current through the tube as indicated on the PLATE

meter, and note the reading of the PERCENT QUALITY meter.