Tektronix 7B51 Instruction Manual page 42

Maintenance-Type 7851
Insert the Type 71351 and a vertical plug-in unit into
a calibrated oscilloscope . Turn,the power on and
allow a few minutes warm-up . Check that all push-
buttons will light when pressed .
Set horizontal and vertical POSITION controls to
midrange, press the top TRIGGERING buttons, set
the TIME/DIV to .5 ms, MAGNIFIER to X1, and
vertical VOLTS/DIV to 10 mV. Advance the Inten-
sity until a free-running trace is observed .
Ro tate the horizontal POSITION control through-
Lout its range . Check for movement of trace .
Set the oscilloscope Calibrator to 1 kHz and 40 mV.
Connect the Calibrator output to the vertical unit.
Check for about 5 complete cycles/10 divisions.
Set the TIME/DIV to 5 ms and press the X10 MAG-
NIFIER button . Check for about 5 complete
cyc l es/10 divisions .
moves along the trace .
4-4
W
yes
button and repeat the above check .
yes
Insert the Type 71351 into the left (A) horizontal
compartment and the companion time-base into the
right (B) horizontal compartment . Set the oscillo-
scope horizontal mode to A . Set the Type 71351
TIME/DIV to .5 ms and press the B STARTS
AFTER DELAY pushbutton . Set the B time-base
TIME/DIV to .1 ms . Check for an intensified por-
NOTE : An Indicator Oscillo-
scope having two hori-
zontal plug-in compart
ments is required for the
following checks .
Rotate the DELAY TIME MULTIPLIER through-
out its range. Check that the intensified portion
Press the B TRIGGERABLE AFTER DELAY push-
buttons do
not light
trace does
not appear
trace does
no
no
Fig . 4-2 . Troubleshooting chart for the Type 71351 .
Check at +5 volt test point
for +5 volts . Check push-
button light bulbs .
Remove vertical unit from
indicator oscilloscope .
Check for free-running
trace .
Check horizontal pre-amp .
Check that VARIABLE
TIME/DIV is set to CAL
IN (pushed in) .
yes
Check hors
zontal pre
amp . Check
rel ay K780-',
Check delay comparator,
delay multivibrator and de-
lay output emitter-
follower. Check delay con-
trol (TP 490) for +4 .5
outputs present
See instruction
manual for indicator
oscilloscope and B
j time-base.
Check DELAY
no TIME MULTI-
PLIER potentio-
meter . Check delay
comparator .
no trace
trace appears
Check delay control
(TP 490) for about
+3 volts . Check
switch S490B .