Simpson 1000 - Page 19

TUBE INFORMATION
and connects it into the ohmmeter circuit. If there is
any leakage resistance, the path will probably be be-
tween the screen grid and the control grid, or between
the screen grid and the suppressor grid.
19. For the last short test, press button H. When you press
this button, the F button returns to its up position and
the screen grid is again connected to ground. The H
button transfers the plate circuit, through the #8 base
pin, to the ohmmeter circuit. If there is any leakage re-
sistance, the path is probably between the plate and the
suppressor grid. This completes the short tests, and
each element has been checked for any leakage path to
the next adjacent element in the tube.
20.If all the short tests indicated that the tube has satis-
factory resistance between each of its elements, the
value can now be tested. The information under VALUE
on the roll chart shows that the H button should be
pressed in for this test. In the 6AG7, this happens to be
the last button which was pressed for the short test,
and it is still pushed in so you can continue. In other
tube listings, this will not generally be the case, and
another button must be pressed according to the listing
“under VALUE. When the new button is pressed, the last
one used for shorts will be released to its up position.
21. Next, press the LINE TEST button. This switches the
control grid, screen, and plate circuits through the #4,
#6, and #8 base pin circuits respectively, from ground
to the proper tube voltages which were set up with the
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