Simpson 1000 - Page 43

SPECIAL APPLICATIONS
between the cathode and filament.
To determine which of two possible paths has the leakage
resistance, increase the number of elements isolated for
the short tests. The path can then be identified through a
process of elimination.
Push buttons A through J are each identified with any
element of any tube through the base arrangement of the
tube. Consult a tube manual to determine which base pin
is associated with each element in the tube. Then the push
buttons can be associated with the elements. Pin #1 uses
the A button, #2 uses the B button, #3 uses the C button,
#4 uses the D button, #5 uses the E button, #6 uses the F
button, #7 uses the G button, #8 uses the H button, #9 uses
the I button, and the cap lead uses the J button.
Through this association, the elements which are separated
for the standard short tests can be identified. If the other
elements (except the filaments) are added to the ones
which are specified for the tube, the second element in-
volved in a leakage path will be identified by having a
reading similar to that of the first element which was
checked.
As an example, suppose that the meter indicates 100K
when the E button is-pressed while testing the 6AG7 as
discussed in Section II. The E button is in the circuit for
the #5 base pin. Referring to the base arrangement, the #5
base pin is the cathode connection. So the 100K resistance
could be between cathode and filament, or between cathode
and control grid. The filament can not be separated, but
the control grid can be separated for a short test. The
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