Simpson 1000 - Page 20

22.
Pag
18
TUBE INFORMATION
K toggle switch and the BIAS control. The tube con-
ducts its normal currents through the same circuits
which it will during the tube test which will follow, but
the meter is connected to check the LINE ADJUST-
MENT control setting. Some high current tubes will load
the transformer enough to reduce the voltage outputs of
the secondaries. Reset the LINE ADJUSTMENT control
for proper meter indication at the ADJ. LINE mark on
the scale.
Press the TUBE TEST button. This will place the
meter circuit (with adjusted sensitivity) in the plate
circuit of the tube. The plate current of the tube, which
is directly proportional to its Plate Conductance value,
will cause the meter to indicate what percent it is of
the expected 30 milliamperes which should flow through
the plate circuit of a normal new 6AG7 tube. While the
tube is being tested, push buttons H, LINE TEST, and
TUBE TEST are pressed in. When the test is complete,
press the red button labelled RELEASE, and all three
of these black buttons will return to their up positions.
All voltages except filament are removed from the tube,
and all the elements except the ‘‘hot’’ side of the fila-
ment are connected to ground.
Remove the tube from the socket. Return all toggle
switches to 0. If no further testing is to be done, rotate
the LINE ADJUSTMENT control to OFF, and the instru-
ment will be disconnected from the line voltage. The
condition when the
meter will indicate this ‘‘no power’
pointer rests at the left hand side of the scale.