VARIABLE
VOLTS/CM
(A
and
B)
full
right
(cw)
POLARITY (A and B)
NORMAL
AC-DC (A
and B)
DC
DC BAL (A and
B)
mid-range
MODE
switch
ALTERNATE
2. Balancing
Output Stage
Connect a shorting strap
between pins 1
and
3 of the 16-pin interconnecting plug. Note
the
vertical
level of the trace. What you
have
just
found is the vertical-system
electrical
center
of the oscilloscope.
Now
connect the shorting
strap between pins
2 and 7
of V4383. The trace should now
fall
within 2 cm of the vertical-system electrical
center just
observed If it
doesn’t, select a
new
tube
for V4383 which will
bring it
within
this
tolerance.
3. Adjusting DC BAL (R3341 and
R4341)
Position the
trace of each channel to the
center
graticule line. Now while rotating
the
VARIABLE VOLTS/CM control through
its
complete range,
adjust the DC BAL so
that
the trace will remain stationary. This
must
be done to each
channel.
4. Vertical
Position Range
Adjustment
(R4376)
Set both of the
VERTICAL POSITION controls
to
mid-range. Adjust the Vert. Pos.
Range
adjustment so
that the
two traces will be
equidistant
above and
below the vertical-system
electrical
center found in step 2.
5.
Checking
POLARITY
Switch
the
trace is within 2 cm of the vertical-system
electrical
center.
With the MODE switch back in the ALTER
NATE
position measure the voltage from
pin
1
or
3, of the 16 pin interconnecting plug,
to
ground. This voltage
should be between
66.5 volts
and
68 volts.
6.
Check for
Gas and Microphonics
Gas
check:
With the
input connectors grounded
turn the AC-DC switches from DC to AC
and observe the
vertical drift of the traces.
This drift
should not be more than 2 milli
meters.
Microphonic
check: Rap the Type
CA
Unit
lightly
on
the
front
panel and watch for the
excessive ringing type of microphonics.
7. Check
for Proper ALTERNATE
CHOPPED
Operation
Reset the oscilloscope's
TIME/CM control
to
.1 SEC and with the plug-in MODE switch
in ALTERNATE, position the
two traces about
2
cm
apart. Check
to see that each time the
sweep
is
triggered the
trace alternates between
A and
B channels.
For
the
CHOPPED check set the
TIME/CM
switch
on the
oscilloscope
to 10 microsec and
the
plug-in
MODE switch
to CHOPPED. Observe
that
the
wave
form should
be approximately
flat
on
the top
and bottom.
8. GAIN ADJ. (R3356 and
R4356)
Set
oscilloscope
as
follows:
TIME/CM
1
MILLISEC
AMPLITUDE
.1 VOLT
CALIBRATOR
With the MODE switch in ALTERNATE
position the traces to the center of the CRT.
Now
switch the POLARITY switches from
NORMAL
to INVERTED.
The traces
should
not
shift
more than one centimeter.
Set
the Type
CA
as follows:
MODE
ALTERNATE
VOLTS/CM ( A and B) .05
Switch
the
MODE switch to ADDED
ALGEBRAICALLY
and the
POLARITY switches
to
NORMAL.
Position the VERTICAL POSITION
controls
to
mid-range
and check to see that
VARIABLE VOLTS/CM
(A
and B)
AC-DC
(A and B)
AA
full
right (cw)
DC
Calibration
- Type
CA
5-3