Simpson 1000 - Page 35

THEORY OF OPERATION
is automatically released to its up position.
After the short tests are complete, the push button switch
which controls the plate circuit of the tube under test is
pressed in and left for the line test and tube test.
When the meter polarity needs to be changed for special
applications, the K push button will be listed under VALUE
on the chart. Press the K push button when it is required
by the test. This will not release any other push switchès.
LINE TEST BUTTON
The LINE TEST button applies operating voltages to the
tube elements and places the meter in the circuit to indi-
cate that the LINE ADJUSTMENT control is properly set
at just the instant the tube goes into its value test. If there
has been a change of line voltage since the short tests
began, or if the tube passes enough current to load the
transformer and reduce secondary voltages, this indication,
just before the value test, will show the results and the
control should be corrected to provide the exact voltages
which are required for proper value indications.
TUBE TEST BUTTON
The final TUBE TEST opens the plate circuit to the tube
and places the adjusted meter circuit in series to measure
the plate current through the tube when the TUBE TEST
push button is pressed. There will be either three or four
push buttons pressed in while the tube is evaluated: the
plate button for the tube (listed under VALUE in the chart),
the LINE TEST button, and the TUBE TEST button: the
fourth will be the K button, when it is specified under
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