Maintenance
—
Type
575
range
to
move
the
beam
completely
across
the
face
of
the
crt,
or
if
the
trace
shifts
horizontally
as
the
VOLTS/DIV
switch
is
rotated.
When
the
unbalance
is
slight, as
in
the
case where
the
trace
shifts
horizontally
as
the
VOLTS/DIV
switch is
rotated,
it
can
usually
be
corrected
by
readjusting
the
DC BAL control.
When
the
unbalance
is
more
pro
nounced,
however,
it
will
be
necessary
to
determine
which
stage
is
producing
the
unbalance
and
to
make
the
necessary
repairs.
If
the
unbalance
occurs
in
all
positions
of
the
VOLTS/DIV
switch
one
of
the amplifier stages is
probably
at
fault
To
determine which stage is
producing
the
unbalance,
a short
jumper
can be used. If
the
beam
is
deflected
off
the
face
of
the
crt
due
to
an
unbalanced
amplifier,
the
beam should re
turn
to
the
face
of
the
crt
when
the
jumper
is
placed
between
the
horizontal
deflection plates
at
the
neck
of
the tube.
The
stage
causing
the
unbalance
can
then be
found
by
jumper
ing
successively
between
corresponding
points
on
opposite
sides
of
the
horizontal
amplifier.
As
you
short
between
the
points,
in
turn,
you
should
see the
beam
return
to
the
screen
as
each
connection
is
made. When
you
reach
a
point
where
the
spot
does
not
return
to
the screen, the
stage
immediately
following
that
point is
at
fault,
unless
the
feedback
networks
from
the
plates
of
the
output stage
to
the
cathodes
of
the
input
stage
are
defective.
The
unbalance
will
usually
be
caused
by
a
defective
tube
or
resistor.
Abnormal
gain
troubles
will generally be
either
insufficient
gain
or
no
output.
The
gain
of
the
amplifier
in
each
position
of
the
VOLTS/DIV
switch
can
be
checked
by
means
of
the
calibration
voltage
applied
to
the
amplifier
by
the
AMPLI
FIER
CALIBRATION
switch.
Using
this
switch
you
should
ob
tain
10
divisions
of
horizontal
deflection
regardless
of
which
position
the
VOLTS/DIV
switch is
in. If,
when
using
the cali
bration
voltage,
abnormal
gain
occurs
only
in
certain
posi
tions
of
the
VOLTS
DIV
switch,
the
resistors
switched
between
the
cathodes
of
V344
and
V354
in
these
positions
should
be
checked.
It
is
possible
that
the operation
of
the
amplifier
will
ap
pear
normal
using
the
calibration
voltage
but
abnormal
when
the
amplifier is
used
in
displaying
transistor
curves.
In
such
a
case one or more
of
the
attenuator
resistors
are probably
defective.
If
the
gain
is
abnormal
in
all
positions
of the
VOLTS/DIV
switch
when using
the calibration
voltage,
at least
one
of
the
amplifier
stages
is
defective.
If
the
gain
is
only
slightly
ab
normal,
the
amplifier
may
be
recalibrated
for
the
correct
gain
using
the
procedure
given
in
the
Recalibration
section.
If
the error
in
gain
is
more pronounced or
if
there
is
no
out
put,
you
should
check
the
tubes
first.
Then
check
for
com
ponents
which
will
affect
the
gain
of
both
sides
of
the
am
plifier
without
unbalancing
the
amplifier,
such
as
common
cathode
resistors.
Troubleshooting
the Vertical Amplifier
Troubles
which
may
occur
in
the vertical
amplifier
are
much
the
same as
those which
occur
in
the
horizontal
ampli
fier
since
the two amplifiers
are
virtually
identical.
Therefore
the
same
general
troubleshooting
techniques may
be
applied
to
the
vertical
amplifier
as
were
described
for
the
horizontal
amplifier.
There
is
one
difference between
the
two
amplifiers
however, that is
worthy
of
note.
That
is
the
location
of
the
collector
sweep
current
sampling
resistors
in
the vertical
am
plifier.
The
current
sampling
resistors
must
conduct
the
en
tire
collector current
of
the
transistor
under
test.
Consequent
ly,
if
one
of
the
resistors
is
open
no
collector
current
will
flow
when
the
CURRENT OR
VOLTAGE
PER
DIVISION
switch
is
in
any
position
where the
open
resistor
is
part
of
the
series
string
composing
the
current sampling
resistor.
Since
some
of
the
current
sampling
resistors
have
a
very
small
value
of
resistance
and
must
remain
within
close
toler
ances,
it
is
impossible
to
check
some
of
these
resistors
with
out
a
precision
ohmmeter.
If
you
find
it necessary
to check
the
value
of
one
of
these
resistors,
it
will
be
necessary
for
you
to
use
a
resistance
bridge
or
other
suitable
device.
Troubleshooting
the Step Generator
For
purposes
of
troubleshooting,
the
step
generator
can be
divided
into
two
parts.
One
portion
[pulse generator,
of
the
circuit
generates
a
continuous
train
of positive
pulses
which
are
applied
to the
other
half
of
the
circuit.
The
second
portion
(stairstep
generator)
of
the
circuit
then
utilizes
these
pulses
to
generate
the
output
stairstep
voltage
waveform.
When
a
trouble
occurs
in
the
step
generator, the
trouble
can
many
times
be
isolated
to
either
the
pulse
generator
or
to
the
stairstep
portions
of
the
step
generator
by
checking
the
output
waveform
with
the
STEPS/SEC
switch
in
the
240 po
sition.
Troubles
which
affect
either
the
number
of steps
per
second
or
the
amplitude
of
the
steps will
generally
be
located
in
the
pulse
generator
section.
Troubles
which
affect
the number
of
steps
per
family or
cause
a
variation
in the
amplitude
of the
steps
will
generally
be
located
in
the
stairstep
generator
sec
tion.
If
no
output
at
all
results,
the
trouble
may
be
in
either
the
pulse
generator
or
the
stairstep
generator.
A
trouble
can
be
isolated to
either
the
pulse generator
or
stairstep
generator
portions
of
the
step generator
by
means
of
the following check. Place
the
STEPS/SEC
switch
in
the
240 position,
remove
tube VI63,
and
connect
the
input
of
a
fest
oscilloscope
to
pin
3
of
V143A.
On
the
test
oscillo
scope
you
should
observe
a train
of positive
pulses
of
ap
proximately
115
volts
peak
amplitude
occuring
at a
240
cycle
rate.
If
this
indication
is
normal,
the
trouble
is
located
in
the
stairstep
generator
section
of
the
step
generator. How
ever,
if
this
indication
is abnormal,
either
in
amplitude
or
in
repetition
rate,
the
trouble
is
located
in
the
pulse
generator
portion
of
the
step
generator.
Tube
VI63
should
be
replaced
as
soon
as
this
check
is
complete.
Troubleshooting
tech
niques
for
the
pulse
generator
and
stairstep
generator
sec
tions
of
the
step
generator
are
discussed
separately
in
the
following
paragraphs.
Pulse Generator
The
best
way
to
troubleshoot
the
pulse
generator
is
to
trace
the
signal
flow
through
the
circuit using
a
test
oscillo
scope.
Checking
the
outputs of the full
wave
rectifier
circuits
is
a
good
place
to start.
The
waveforms at
the
output
of
the
rectifier
circuits
(VI
12
and
V123)
are
given
on
the
schematic
diagram
of
the
step
generator.
If
the
outputs
of
either
or
4-6
®®>
Summary of Contents for 175
Page 4: ...VWTICM OINltAlO TRANSISTOR CUM TRACfR UB l COUlClO r hokizoniai VCKIJ O lUnK Hix M Type 575 z ...
Page 6: ...NOTES ...
Page 26: ...NOTES ...
Page 48: ...NOTES ...
Page 54: ...Recalibration Type 575 C706 Fig 5 3 Left Side View 5 6 ...
Page 56: ...NOTES ...
Page 100: ...INPUT AMPLIF1E ...
Page 104: ...TYPE 575 TRANSISTOR CURVE TRACER ...
Page 108: ...OSCILLATOR 4OOV UNREG TYPE 575 TRAN5I5TOR CURVE TRACER AB ...
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Page 119: ...Type 175 Tent S N 570 PARTS LIST CORRECTION Change to Q233 151 0137 00 2N21U8 MIO 298 1165 ...