Simpson 1000 - Page 18

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TUBE INFORMATION
1s set correctly. Correct its setting, if necessary, to
make the meter indicate at the ADJ. LINE mark on the
scale. Proceed with the short tests next.
Press the push button labelled E. This transfers the
connections to the cathode of the tube through the #5
base pin circuit. The leakage resistance, if there is
any, between the cathode and any other tube elements,
will be in series with the .25 microfarad capacitor, and
this circuit will be in parallel with the resistance which
is connected between the positive meter terminal and
ground. As the leakage resistance reduces in value, the
amount of current through the meter will increase, and
the pointer will be deflected further to the right on the
scale. The meter scale which reads leakage resistance
in ohms will indicate what amount of leakage is present
between the tube elements. If there is a dead short, the
meter current will increase to 200 microamperes, and
the pointer will be deflected to full scale to indicate
zero ohms of leakage between the cathode and some
other element in the tube. If there should be any leak-
age resistance shown when the E switch is pushed
down, the path would probably be either from cathode to
heater, or from cathode to control grid. If you wish to
determine which of these paths is involved, see the in-
formation in Section V, Special Applications.
The next short test calls for pressing button F. When
the F button is pressed, the E button returns to its up
position and the cathode is again connected to ground.
The F button now separates the screen grid, through the
#6 base pin circuit, from the other elements of the tube