Heathkit TT-1 - Page 14

phart of
Ullait UL
natinntt
Typical Operation
manual, it is notedthat abias value
of -1.0 volt should be used in conjunction
with the 100 volt plate voltage. One volt
bias corresponds to a setting of 10 L.
(Always use as high a value of bias as pos-
sible, consistent with obtaining a useable
meter reading. The high bias value will pre-
vent the flow of excessive plate current
which might damage the tube, the tester,
or both.)
The SIGNAL switch should be at Position 8.
The METER control should be at max-
imum counterclockwise
K. P and G switches shouldbe in Position 1.
“3 7 wil
LEAKAGE switch in Position 1.
Plug in the tube and observe it closely as it
warms up. Turn off the power tothe TT-1 at
any sign of sparking, gas ignition, over-
heating, etc. Excessive dimming of the panel
lamps may be another indication of trouble.
Should any of these unusual conditions exist,
carefully recheck the setting of the SE-
LECTOR switches.
After the tube has
warmed up, rotate the
LEAKAGE
switch
through
all
positions.
If
the
tube
passes
all
leakage
tests,
place
LEAKAGE
switch
in
TUBE
TEST
position.
Pull
down
the
Gm
test
switch
and
advance
the
METER
control
until
the
meter
shows
an
indication.
Half-scale
deflection
(LINE
The Heath Company reserves the right to discon-
tinue instruments and to change specifications at
any time without incurring any obligation to
10.
1
pu
to
1.
tube to be responding to the AC signal volt-
age injected at the grid. Proceed to make the
other usual tests on the tube (grid current,
etc.).
If no meter reading was obtained in Step 9
above, returnthe METER control to its max-
imum counterclockwise position and ad-
yance the SIGNAL switch to the next hicher
AAs Ves Wana S a a Wass VE Veet Seeks acess’
signal voltage (Position 4). Again advance
the METER control. If no meter reading is
obtained, move the SIGNAL switch to Po-
sition 2. Continue on to Position i if neces-
sary. ALWAYS start with METER control
maximum counterclockwise to avoid "pin-
ning’’ the meter.
If, after advancing signal voltage to Position
1, no meter reading is obtained, cautiously
increase the DC plate current through the
tube by either increasing the plate voltage
or decreasing the bias.
When maximum conditions have been reach-
highest
2h2 .¥
re
anat ee
Ll
ay be assumed the tube is compieteiy ine
operative and should be replaced. Your own
experience and knowledge must be relied
upon to decide upon replacement in cases
where excessive voltage and signal condi-
tions are required to produce a meter read-
ing.
incorporate new features in instruments pre-
viously sold,
To order replacement parts,
Por, Dawta
"Replacement
farts Pr ice List
refer to the
teot!! and ne
and use the
Parts Order Form furnished with this kit,