37. Tube Replacement
When trouble occurs, check the power cord connection and the
control settings before removing any tubes. If tube failure is
suspected, use the tube s u b s t i t u t i o n m e t h o d (a b e l o w ) t o c h e c k
Caution: Do not rock or rotate a tube when removing it from
a socket; pull it straight out with a tube puller.
tube ( b
below) with a new tube. If the equipment still does not work,
remove the new tube and put back the original tube. Repeat this
procedure with each suspected tube until the defective tube is
Check the tubes in the tube tester as follows:
( 2 ) Remove the shields of the 6X4 or 6X4W tubes (V2 and
V3) by pressing down on the shield and rotating coun-
terclockwise until it is released.
( 3 ) Release
down on the spring which engages the threaded portion
( 4 ) Use a tube puller to remove the tube. If a tube puller is
not available, allow the tube to cool, and then grasp it,
and pull the tube straight up.
( 5 ) If a tube marking has become illegible, label the tube as
s o o n as it is removed.
tube (a above)
( 7 ) Set the tube (or a replacement) in the socket and secure
it (by replacing tube retainer or shield).
( 8 ) Replace the chassis in the case (par. 36b).
A preferred-type electron tube, type 6X4W, has been developed
tube is used in the power supply. When replacement of a 6X4
type tube is necessary, replace it with a 6X4W type tube. Do not
substitute a 6X4 tube for a 6X4W tube.