Maintenance—Type
535A
troubleshooting
the Vertical Amplifier.
The
horizontal de
flection
plates
are marked RED (LEFT) and GREEN (RIGHT).
The
INTENSITY
control
should be set to midscale. If a spot
appears
when the
horizontal deflection plates are shorted
together
(it
may be necessary to
adjust the
Vertical POSI
TIONING control),
the
trouble lies in the Horizontal Ampli
fier.
CAUTION
Exercise
care in checking the power supply. Be
cause
of
their high current
capabilities and low
impedance,
the Low-Voltage supplies can produce
more harmful
shocks
than the high-voltage supply
in the
CRT circuit.
CAUTION
Do
not
permit
the
spot to remain on
the crt at
this
setting of the INTENSITY control. Either re
duce
the intensity until the spot is just visible, or
remove the
short
from the horizontal deflection
plates.
The
procedure
for troubleshooting the Horizontal Ampli
fier
to locate the defective stage, is similar to that explained
for
troubleshooting the
Vertical
Amplifier
for unbalance. The
shorting strap
can be moved
from the
deflection plates back
toward
the Input Amplifier stage, until a point is reached
where
the trace
does not appear. When the stage at fault is
determined,
check for defective tubes and components as
sociated with
that stage.
Insufficient
or
No Horizontal Deflection
If the
gain of the Horizontal Amplifier decreases,
the
trace
will not extend from the left to the right side of the
graticule, in
addition,
the timing will no longer correspond
to
the calibrated value indicated by the TIME/CM switch,
(This is
to distinguish the
condition of insufficient sweep
produced
by a malfunction in the Horizontal Amplifier from
that
Hold-Off Circuit in the Time-Base Generator, e.g. an
improper
adjustment of
the Swp.
Length control. In
the lat
ter case
the trace
will
start
at the left side of
the graticule,
for the
normal setting of the HORIZONTAL POSITION con
trol, and
the timing will
not be affected.)
If
the
change in gain is
slight, as indicated by improper
timing
and a slightly decreased sweep, the amplifier can
usually be recalibrated. Since
the gain of the Horizontal
Amplifier regulates
the timing of
the sweep, care must be
taken
to insure that the
gain adjustments are accurately
made.
Be sure to
refer to the Calibration Procedure if it
is necessary to adjust
the gain
of the Horizontal Amplifier.
If
the decrease in gain of
the
Horizontal Amplifier is more
pronounced,
or if there
is no sweep at all (in which case
only a
spot will
be visible on the horizontal axis), check for
defective
components which
can affect
the gain
but not the
d
c balance.
In addition to
the tubes, such
components
would
be the common cathode resistors and controls.
TROUBLESHOOTING LOW-VOLTAGE
POWER SUPPLY
Proper
operation of every circuit
in your instrument de
pends on
proper operation of the
Power Supply. The regu
lated
dc
voltages must remain within their specified toler
ances
for
the
instrument to retain
its calibration.
Open Power
Circuit (Dead
Circuit)
If
the
pilot
lamp and the fan do not come on when the
power
is turned on, check the source of
power and the
power
cord connections. Check the fuse. If the fuse is
blown replace
it with
one of the proper value and turn the
instrument on again. If
the new fuse blows immediately,
check the
power
transformer for shorted primary or sec
ondary
windings. Also check for shorted rectifiers. If the
new
fuse
does not blow until the time-delay relay has acti
vated (a
"click" can be heard),
check for a shorted condition
in
the
regulator circuits and the loading on the supply.
Fig.
5-14.
Location of power supply and Calibrator test points.
If
the fuse is good, check for an open primary winding in
the
power transformer. If your instrument is wired for 234-
volt
operation,
check for an open Thermal Cutout Switch; the
resistance
of this switch is about 0.1Ω. (If your instrument
is
wired for
117-volt operation, the fan will come
on even
though
the Thermal
Cutout Switch may be open).
If
both the fan and pilot
light come on, the primary cir
cuit of the power transformer is operating normally.
Incorrect
Output Voltage
The voltage for each
test point is silk-screened on the lip
of
the chassis adjacent to the ceramic strip
on which the
5-11
Summary of Contents for 535A
Page 2: ......
Page 4: ...Type 535A ...
Page 28: ...Circuit Description Type 535A 4 2 Fig 4 1 Simplified Type 535A Vertical Amplifier ...
Page 30: ...Circuit Description Type 535A 4 4 Fig 4 2 Simplified Time Base Trigger Circuit ...
Page 32: ...Circuit Description Type 535A Fig 4 3 Simplified Time Base Generator 4 6 ...
Page 34: ...Circuit Description Type 535A 4 8 Fig 4 4 Simplified Delay Pickoff Circuit ...
Page 38: ...Circuit Description Type 535A Fig 4 6 Simplified Alternate Trace Operation Circuitry 4 12 ...
Page 39: ...Circuit Description Type 535A 4 13 ...
Page 41: ...Circuit Description Type 535A Fig 4 8 Simplified Low Voltage Power Supply 4 15 ...
Page 42: ...Circuit Description Type 535A 4 16 Fig 4 9 Simplified Calibrator Circuit ...
Page 44: ...Circuit Description Type 535A Fig 4 10 Simplified Cathode Ray Tube Circuit 4 18 ...
Page 126: ...MRU ll IG 61 O Z ...
Page 138: ...C897 R896 R891 R890 R889 R888 R887 R886 R885 AMPLITUDE CALIBRATOR SWITCH Bottom View 535A A ...
Page 143: ...FIG 1 FRONT SWITCHES TVDC COCA ocril I iCrODC ...
Page 144: ...70 ...
Page 145: ...1 FIG 3 SWEEP CHASSIS HIGH VOLTAGE BOARD DELAY SWEEP CHASSIS ...
Page 146: ...1 FIG 4 POWER CHASSIS RECTIFIER MOUNTING PLATE A ...
Page 147: ...3 34 79 ...
Page 148: ...TYPE 535A OSCILLOSCOPE ...
Page 149: ......
Page 150: ...FIG 7 CABINET FRAME RAILS ...
Page 152: ...FIG 8 STANDARD ACCESSORIES 6 TYPE 535A OSCILLOSCOPE ...
