Tektronix 7B51 Instruction Manual page 43

Maintenance-Type 7851
Insert the Type 7B51 and a vertical plug-in unit into
buttons do
Check at +5 volt test point
a calibrated oscilloscope. Turn ·the power on and
not light
for +5 volts. Check push-
allow a few minutes warm-up. Check that all push-
button light bulbs.
buttons will light when pressed.
buttons light
Set horizontal and vertical POSITION controls to
trace does
Remove vertical unit from
no trace
midrange, press the top TRIGGERING buttons, set
not appear
indicator oscilloscope.
the TIME/DIV to .5 ms, MAGNIFIER to Xl, and
Check for free-running
vertical VOL TS/DIV to 10 mV. Advance the Inten-
trace.
sity
until a free-running trace is observed.
I
trace appears
trace appears
trace does
Rotate the horizontal POSITION control through- I
not move
: Check horizontal pre-amp.
out its range. Check for movement of trace. I
trace moves
Return VARIABLE con-
trol to CAL IN.
~
t
no
Set the oscilloscope Calibrator to 1 kHz and 40 mV.
no
Check that VARIABLE
Connect the Calibrator output to the vertical unit. TIME/DIV is set to CAL
Check for about 5 complete cycles/10 divisions.
IN (pushed inl.
yes
I
yes
Check hori-
Set the TIME/DIV to 5 ms and press the Xl0 MAG-
no
zontal pre-
NIFIER button. Check for about 5 complete
amp. Check
cycles/l0 divisions.
relay K780.
yes
NOTE: An Indicator Oscillo-
scope having two hori-
zontal plug-in compart-
ments is required for the
Check delay comparator,
following checks.
delay multivibrator and de-
lay output em itter-
follower. Check delay con-
Insert the Type 7B51 into the left (AI horizontal
no
trol (TP 4901 for +4.5
compartment and the companion time-base into.the
volts.
right (BI horizontal compartment. Set the oscillo-
~
outputs present
scope horizontal mode to A. Set the Type 7B51
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-
See in st ruction
tion on the display.
manual for indicator
oscilloscope and B
yes
time-base.
Check DELAY
Rotate the DELAY TIME MULTIPLIER through-
no
TI M E
M U L TI-
out its range. Check that the intensified portion
PLiER potentio-
moves along the trace.
meter. Check delay
comparator.
yes
Check delay control
Press the B TRIGGERABLE AFTER DELAY push-
no
(TP 4901 for about
button and repeat the above check.
+3 volts. Check
switch S490B.
Fig. 4-2. Troubleshooting chart for the Type 7B51.
4-4
®