LEADER lbo-516 User Manual
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TABLE OF CONTENTS (Continued)
3-4 CALIBRATION OUTPUT ADJUSTMENT ...................................................................................................... 30
3-5 A TIMEBASE ALIGNMENT ........................................................................................................................... 30
3-5-1 Slow Sweep Time ................................................................................................................................. 30
3-5-2 Sweep Length .......................................................................................................................................30
3-5-3 Fast Sweep Time .................................................................................................................................. 30
3-5-4 Sweep Start Point .................................................................................................................................30
3-5-5
Timebase Accuracy Check .................................................................................................................... 30
3-6 A TIMEBASE X10 MAGNIFIER ADJUSTMENT ........................................................................................... 30
3-6-1 Magnifier Positioning ........................................................................................................................... 30
3-6-2 Magnifier Speed Accuracy ....................................................................................................................30
3-7 B TIMEBASE ALIGNMENT ........................................................................................................................... 30
3-7-1 Slow Sweep Time ................................................................................................................................. 30
3-7-2 Length Adjustment ...............................................................................................................................31
3-7-3 Sweep Start Point .................................................................................................................................31
3-7-4 Fast Sweep Time .................................................................................................................................. 31
3-7-5 Timebase Accuracy Check ....................................................................................................................31
3-7-6 Start Points Alignment ..........................................................................................................................31
3-8 VERTICAL AMPLIFIERS ...............................................................................................................................31
3-8-1 DC Balance Adjustment ........................................................................................................................31
3-8-2 Attenuator Step Balance ........................................................................................................................30
3-8-3 X1 AC Gain Compensation ................................................................................................................... 31
3-8-4 X10 AC Gain Compensation ................................................................................................................. 31
3-8-5 Gain Calibration ................................................................................................................................... 31
3-8-6 CH-2 Invert Balance Adjustment ........................................................................................................... 32
3-8-7 CH-1/CH-2 Input Capacitance Adjustment ............................................................................................32
3-8-8 CH-1/CH-2 Input Attenuator Compensation ..........................................................................................32
3-8-9 CH-3 Direct Input Capacitance Adjustment ...........................................................................................32
3-8-10 CH-3 Attenuator Compensation .......................................................................................................... 32
3-8-11 CH-3 Attenuator Input Capacitance Adjustment ...................................................................................32
3-8-12 CH-3 Gain Adjustment ....................................................................................................................... 32
3-8-13 CH-1 Output Level Adjustment ........................................................................................................... 32
3-8-14 CH-1/CH-2 HF Pulse Response Alignment .......................................................................................... 32
3-8-15 CH-1/CH-2 Frequency Response Check .............................................................................................. 33
3-8-16 CH-1 Output Pulse Response .............................................................................................................. 33
3-8-17 CH-1/CH-2 X10 Magnifier Bandwidth Check .....................................................................................33
3-8-18 Vertical Position Control Centering ..................................................................................................... 33
3-8-19 ADD Balance Adjustment ................................................................................................................... 33
3-9 TRIGGER CIRCUITRY ADJUSTMENTS .......................................................................................................33
3-9-1 Trigger Balance and Centering Alignments ........................................................................................... 33
3-9-2 Trigger Balance Adjustments for Multitrace Modes ...............................................................................33
3-9-3 Preset Trigger Adjustment .................................................................................................................... 34
3-9-4 CH-3 Pulse Response Adjustment .........................................................................................................34
3-9-5 Internal Trigger-Pulse Response Adjustment ......................................................................................... 34
3-10 X-Y MODE ADJUSTMENTS .................................................................................................................. 34
3-10-1 Gain Adjustment .................................................................................................................................... 34
3-10-2 Balance Adjustment ...............................................................................................................................34
4. REPLACEMENT PARTS LIST 37
5. BLOCK DIAGRAM, SCHEMATICS AND P.C. BOARDS 51
3. MAINTENANCE AND CALIBRATION
3-0.
The following test equipment is required to perform the
calibration/maintenance procedures described in this section.
The performance specifications given are the minimum
necessary to accurately calibrate the oscilloscope.
Description Minimum Specifications
1. Digital Voltmeter DC Voltage Range: 0-200 VDC
Accuracy: +0.5%
2. High Voltage DC Voltage Range: 0-2000 VDC
Voltmeter Accuracy: -+ 1%
3. Frequency Counter Frequency Range: 100 Hz -
200 MHz
Overall Accuracy: +0.001%
4. Time Mark Generator Marker Outputs: 2nS - 0.5 S with
calibrated
Accuracy: -+0.1%
5. Sine Wave Generator Frequency Range: lkHz - 200 kHz
Output Level: 15 mV - 5 Vp.p
Accuracy: -+.3 dB, 1 MHz - 200
MHz as frequency is changed
6. Test Oscilloscope 100 MHz Bandwidth
7. Square Wave Frequency: 1 kHz - 100kHz, -+1%
Generator Output Level: I mV - 1.0 Vp-p,
-+1%
Rise Time: 3 nS
8. Amplitude Calibrator Output: 1 kHz square wave
Frequency Accuracy: -+0.25%
Output Level: 2 mV - 20 Vp-p
9. Capacitance Meter Range: 0-50 pF
Accuracy: --- 1%
3-1. INITIAL SETUP CONDITIONS
POWER switch ......................…………Pushed in
A INTEN control ............................... Centered*
B INTEN control ................................ Centered*
ILLUM control .................................. Clockwise
FOCUS control .................................. Centered*
AC/GND/DC switches ....................... DC
VOLTS/DIV switches ........................ 20mV
VARIABLE controls .......................... Clockwise
X10 MAG switches ………………… Pushed in
Vertical POSITION controls ......…… Centered*.
PULL QUAD control ...............… Pushed in
PULL TRIPLE control ...............… Pushed in
V MODE switches ...................... … CH-1
CH-2 INV switch ....................... …… Out
DLY TIME MULT control .........…… Counterclockwise.
COUPLING switch ...................…… AC
SOURCE switch ......................……….CH-1
LEVEL control ........................………. 0
HOLDOFF control ..................... Detented counter
A/B TRACE SEP control .............. Centered
SLOPE switch ........................... Out
HORIZ DISPLAY switches. .......... A
START switch .......................... Out
SWEEP MODE switches .............. AUTO
+
5% offset adjust
clockwise and
pulled out
29
A TIME/DIV switch .................... .5 mS
B TIME/DIV switch .................... .1 mS
A VARIABLE control ................. Clockwise
Horizontal POSITION control ........ Centered*
* Adjusted afterwards for best viewing
Allow 30 minutes warmup before making any adjustments. Remove the top and bottom covers to gain access to test
points and internal adjustments.
3-2 POWER SUPPLY CHECK AND ADJUSTMENT
3-2-1 -8 Volt Adjustment
Connect a digital voltmeter's positive lead to the scope
chassis (GND), and the voltmeter's negative lead to TP-5 located on PCB T-3153. Adjust VR-1 for -8.0 V.
3-2-2 Power Supply Check
Check the voltages listed below by moving the
voltmeter's negative lead to chassis ground, and applying the
positive lead, in turn, to each of the associated test points on
PCB T-3153.
Nominal
Test Point Voltage Tolerance
TP-I +100 +98 VDC 'to 102VDC
TP-2 + 50 49 51
TP-3 + 12 11.75 12.25
TP-4 + 8 7.85 8.15
TP-6 + 5 4.8 5.2
TP-7 + 19 17.5 20.5
3-2-3 High-Voltage Adjustment
Turn off the unit under test. Connect the positive lead of a
HV voltmeter to chassis ground, and its negative lead to TP-8.
Turn the scope on and allow a 2 minute warmup. Adjust VR-2
on PCB T-3162 for a reading of - 1950 volts. Connect an X10
probe to the test oscilloscope and hold its tip close to the face
of the CRT under test. The high-voltage ripple displayed on
the test oscilloscope should be less than 0.1Vp-p.
3-3. CRT CONTROL ADJUSTMENTS
Make sure the controls are set according to the initial
setup conditions in Paragraph 3-1 before starting the following
adjustments.
3-3-1 Intensity Range Adjustment
Center the CH- 1 trace on the CRT with the vertical
POSITION control. Set the A INTEN control knob mark to an
approximate 45° angle as shown in Figure 3-1. Adjust VR-I on
PCB T-3162 until the trace becomes just barely visible.
3-3-2 Astigmatism Adjustment
Connect a sine wave generator to the CH-1 input connector. Set generator frequency and output to produce five or six
sine waves. Set output level and POSITION controls for a
centered display 6 cm high. (Peaks of the sine waves just
touching the graticule lines I cm above and below the bottom
and topmost graticule lines.) Adjust A INTENS and FOCUS
for a medium-bright, sharp display. Adjust VR- 1 on PCB T3157 for optimum overall sharpness.
.
.
3-4. CALIBRATION OUTPUT ADJUSTMENT
Connect the test oscilloscope to the CAL connector on the
fron panel of the LBO-516. Adjust VR-1 on PCB T-3287 for a
CAL output level of 0.5 Vp-p +-1%.
square wave should be 45-55%.
Connect the CAL output to a frequency counter; the frequency should be 1000 Hz + - 10%.
3-5. A TIMEBASE ALIGNMENT
3.5-1 Slow Sweep Time
Return the oscilloscope to the initial setup conditions.
(See Paragraph 3-1). Adjust the time-mark generator for an
output of .5 mS and connect it to the CH-1 input connector.
Using the horizontal POSITION control, align the first mark
with the leftmost vertical graticule line. Adjust VR-22 on PCB
T-3158 to align each subsequent mark with a major vertical
graticule line.
3.5-2 Sweep Length
With the same conditions as in the previous paragraph,
adjust the horizontal POSITION control to align the third mark
with the leftmost vertical graticule line. (See Figure 3-2.)
Adjust VR-1 on PCB T-3158 so the 13th mark is fully displayed on the CRT screen.
3.5-3 Fast Sweep Time
Return the oscilloscope to the initial setup conditions.
(See Paragraph 3-1). Set the A TIME/DIV switch to 0.5 PS.
Set the time-mark generator to 0.5/.PS and connect it to the
CH- 1 input connector. Using the horizontal POSITION
control, align the first mark with the leftmost vertical graticule
line. (See Figure 3-2.) Adjust VC-22 on PCB T-3158 to align
each subsequent mark with a major vertical graticule line.
3.5-4 Sweep Start Point
Return the oscilloscope to the initial setup conditions.
(See Paragraph 3-1). Set the A TIME/DIV switch to 0.1 mS.
With the horizontal POSITION control, adjust the trace
startpoint to the first minor division (0,2 major division).
Change the A T1ME/DIV switch to 50/aS and adjust VC-1 on
PCB T-3158 so the sweep starts at the leftmost vertical
graticule line.
3.5-5 Timebase Accuracy Check
Return the oscilloscope to the initial setup conditions.
(See Paragraph 3-1). Set the A TIME/DIV switch to 0.5 S. Set
The duty cycle of the
the time-mark generator to 0.5 S and connect it to the CH- 1
input connector. Align the first mark with the left-most vertical
graticule line. Adjust the generator so that each subsequent
mark is aligned with a major vertical graticule line. Repeat for
each A TIME/DIV switch setting from.2 S to 0.2PS, verifying
that the timebase accuracy is within +-2% at each sweep
speed.
3-6. A TIMEBASE X10 MAGNIFIER ADJUSTMENT
3-6-1 Magnifier Positioning
Return the oscilloscope to the initial setup conditions.
(See Paragraph 3-1.) Set the CH-1 AC/GND/DC switch to
GND, and press the INTEN BY B pushbutton. Set the B
TIME/DIV switch to .5 mS. Adjust the horizontal POSITION
control to start the A trace on the leftmost vertical graticule
line. Adjust the DLY TIME MULT control to start the B
(intensified) trace at the center vertical graticule line. Center
the horizontal POSITION control knob. Pull the timebase X10
MAG switch. Adjust VR-33 on PCB T-3158 so that the B
sweep starts on the center graticule line. Afterward, push in the
X 10 MAG switch knob, and adjust VR-34 on PCB T-3158 so
that the B sweep starts on the center graticule line. Repeat
these two adjustments (VR-33 and VR-34) until the B trace
starts on the center graticule line in both positions of the XI0
MAG switch.
3-6-2 Magnifier Speed Accuracy
Return the oscilloscope to the initial setup conditions.
(See Paragraph 3-1). Connect a time-mark generator set for. 5
mS output to the CH-1 input connector. Set the A TIME/DIV
switch and horizontal POSITION control so every third mark
is aligned with a major vertical graticule line. Pull the X10
MAG knob, then adjust VR-35 on PCB T-3158 so a mark is
aligned with the first, center, and last major vertical graticule
line.
3-7. B TIMEBASE ALIGNMENT
3-7-1 Slow Sweep Time
Return the oscilloscope to the initial setup conditions.
(See Paragraph 3-1.) Set the CH-1 VOLTS/DIV switch to. 1
V. Connect a time-mark generator set for .5 mS to the CH-1
input connector. Set the DLY TIME MULT control to 2.50,
and press the B HORIZ DISPLAY pushbutton. Adjust the
DLY TIME MULT control to align the nearest mark with the
30
leftmost vertical graticule line. Adjust VR-21 on PCB T-3158
to align each of the subsequent marks with a major vertical
graticule line.
3-7-2 Length Adjustment
Return the oscilloscope to the initial setup conditions.
(See Paragraph 3-1.) Connect a time-mark generator set for 0.5
mS to the CH- 1 input connector. Using the horizontal POSITION control, align the third mark with the leftmost vertical
graticule line, and adjust VR-11 on PCB T-3158 so that the
13th mark is fully displayed on the CRT screen.
3-7-3 Sweep StartPoint
Return the oscilloscope to the initial setup conditions.
(See Paragraph 3-1.) Press the B HORIZ DISPLAY
pushbutton. Using the horizontal POSITION control, adjust
the trace start point to a little less than the first minor division
on the center horizontal graticule line (0.15 major division).
Change the B TIME/DIV switch to 50 PS, then adjust VC- 11
on PCB T-3158 so the sweep starts at the leftmost vertical
graticule line.
3-7-4 Fast Sweep Time
Return the oscilloscope to the initial setup conditions.
(See Paragraph 3-1.) Set the A TIME/DIV switch to PS, and
the B TIME/DIV switch to 0.5PS. Press the B HORIZ DISPLAY pushbutton. Connect a time-mark generator set for
0.5PS output to the CH-1 input connector. With the horizontal
POSITION control, align the first mark with the leftmost
vertical graticule line. Adjust VC-21 on PCB T-3158 to align
each of the subsequent marks with the other vertical graticule
lines.
3-7-5 Timebase Accuracy Check
Return the oscilloscope to the initial setup conditions.
(See Paragraph 3-1.) Set the A and B TIME/DIV switches to
50 mS, and press the B HORIZ DISPLAY pushbutton.
Connect a time-mark generator set for 50 mS output to the
CH- 1 input connector. Align the first mark with the leftmost
vertical graticule line. Adjust the generator so each subsequent
mark is aligned with a major vertical graticule line. Repeat the
above for each TIME/DIV setting from 20 mS to .02PS, verifying that the timebase accuracy is within +-2% at each sweep
speed.
3-7-6 Start Points Alignment
Return the oscilloscope to the initial setup conditions.
(See Paragraph 3-1). Set the CH- 1 AC/GND/DC switch to
GND, and the B TIME/DIV switch to 5PS. Press the INTEN
BY B HORIZ DISPLAY pushbutton, and adjust the A and B
INTEN controls for a noticeable difference between the A and
B traces. Using the horizontal POSITION control, make the A
trace start at the leftmost vertical graticule line. Check that the
DLY TIME MULT control is set at 0.2 (fully CCW), then
adjust VR-13 on PCB T-3158 so that the B trace starts at the
minor
first
VR-12 on PC T-3158 to make the B trace start at the rightmost vertical graticule line. Repeat both of these adjustments
until the B trace starts at the proper points.
3-8. VERTICAL AMPLIFIERS
vertical graticule line.
Turn the DLY TIME MULT control to 10.0 and adjust
3-8-1 DC Balance Adjustment
Retain the oscilloscope to the initial setup conditions.
(See Paragraph 3-1). Set the CH-1 and CH-2 VOLTS/DB/
switches to 5 reV, the CH-I and CH-2 AC/GND/DC switches
to GND, and center the trace vertically with the vertical
POSITION control. Then, pull the CH-I X10 MAG switch
knob, and adjust VR-5 on PCB T-3154 to recent
Repeat the above by turning the X10 MAG switch on and off,
and readjusting the vertical POSITION control and VR-5 for
minimum shift.
Press the CH-2 V MODE pushbutton, and repeat the
above procedure for CH-2. VR-15 on PCB T-3154 is the CH-2
adjustment.
3-8-2 Attenuator Step Balance
Return the oscilloscope to the initial setup conditions.
(See Paragraph 3-1). Set the CH-I and CH-2 VOLTS/DIV
switches to 10 mV, and the AC/GND/DC switches to GND.
Center the trace vertically using the CH-I vertical POSITION
control. Change the CH-1 VOLTS/DIV switch to 5 mV, and
adjust VR4 on PCB T-3154 to recenter the trace. Repeat the
above until there is very little shift in the trace when switching
between I0 mV and 5 mV positions of the VOLTS/DIV
switch.
Press the CH-2 V MODE pushbutton, and repeat the
above procedure for CH-2. VR-14 on PCB T-3154 is the CH-2
adjustment.
3-8-3 X1 AC Gain Compensation
Return the oscilloscope to the initial setup conditions.
(See Paragraph 3-1). Set the CH-1 and CH-2 VOLTS/DIV
switches to 5 mV, the A TIME/DIV switch to .2 mS, and press
the ALT V MODE pushbutton.
Connect a square-wave generator to the CH-1 and CH-2
input connectors. Adjust the generator frequency to I000 Hz,
and its output level to 25 mVp-p.Adjust VR- 1 on PCB T-3154
for a correct square-wave display, per Figure 3-3. After
channel 1 is compensated, adjust VR-11 on PCB T-3154 for a
correct channel 2 display.
3-8-4 X10 AC Gain Compensation
With conditions set as in Paragraph 3-8-3, turn both
VOLTS/DB/switches to 20 mV and pull both vertical X10
MAG control knobs. Set the square-wave generator output to
10 mVp-p.
Adjust VR-2 on PCB T-3154 for a correct square-wave
display, per Figure 3-3. After channel 1 is compensated, adjust
VR-12 on PCB T-3154 for a correct CH-2 display.
3-8-5 Gain Calibration
With conditions set as in Paragraph 3-8-4, turn both
VOLTS/DIV switches to 5 mV, and remove the square wave
generator.
Connect an amplitude calibrator whose output is set for
25 mVp-p to the CH-1 and CH-2 input connectors. Adjust VR21 on PCB T-3155 for a CH-1 vertical deflection of~ major
divisions. Adjust VR-23 on PCB T-3155 for a CH-2 vertical
deflection of 5 major divisions.
er
the trace.
31
3-8-6 CH-2 INV Balance Adjustment
Return the oscilloscope to the initial setup conditions. (See
Paragraph 3-1.) Press the CH-2 V MODE switch, and set the
CH-2 AC/GND/DC switch to GND.
Center the trace vertically using the CH-2 vertical POSITION control. Press the CH-2 INV switch, and note the amount
that the trace shifts from the centered position. Using VR-11 on
PCB T-3155, move the trace half the distance it shifted, back
towards the center of the CRT screen. Release the CH-2 INV
switch, and recenter the trace with the CH-2 vertical POSITION
control. Repeat the above adjustments as the CH-2 INV switch
is operated, until there is no trace shift from one position to the
other.
3-8-7 CH-1/CH-2 Input Capacitance Adjustment
Return the oscilloscope to the initial setup conditions. (See
Paragraph 3-1). Set the VOLTS/DIV switches to 5mV.
Connect a capacitance meter to the CH-1 input connector
and adjust VC-1 (Ci-1) on PCB T-3154 for 30 pF. Reset the
VOLTS/DIV switch to 20 mV and adjust 1/2 Ci for 30 pF. Reset
the VOLTS/DIV switch to 50 mV and adjust 1/5 Ci for 30 pF.
Reset the VOLTS/DIV switch to .1 V and adjust l/l0 Ci for 30
pF. Reset the VOLTS/DIV switch to 1 V and adjust 1/100 Ci for
30 pF.
Press the CH-2 V MODE pushbutton, and repeat the above
adjustments on VC-11 for channel 2.
3-8-8 CH-1/CH-2 Input Attenuator Compensation
Return the oscilloscope to the initial setup conditions. (See
Paragraph 3-1). Connect a square-wave generator to the CH-1
input connector. Set the generator controls for 100 mV output at
1000 Hz.
Adjust CH-1 1/2Cc on PCB T-3154 for a correctly compensated
square-wave. (See Figure 3-3.) Reset the CH-1 VOLTS/DIV
switch to 50 mV, and the generator output level for 250 mVp-p.
Adjust CH-1 1/5Cc on PCB T-3154 for a correctly compensated
square wave. Reset the CH-1 VOLTS/ DIV switch to .1 V, and
the generator output level to .5 V. Adjust CH-1 1/10Cc on PCB
T-3154 for a correctly compensated square-wave. Reset the CH1 VOLTS/DIV switch to 1 V, and the generator output level to 5
Vp-p. Adjust CH-1 1/100Cc for a correctly compensated squarewave.
Press the CH-2 V MODE switch, and repeat the above procedure for CH-2, using the CH-2 1/2Cc, 1/5Cc, 1/10Cc. and
1/100Cc adjustment trimmers.
3-8-9 CH-3 Direct Input Capacitance Adjustment
Return the oscilloscope to the initial setup conditions. (See
Paragraph 3-1.) Press the ALT V MODE pushbutton, pull the
PULL TRIPLE control knob, set the SOURCE switch to .2
V/DIV, and the COUPLING switch to DC.
Connect a capacitance meter to the CH-3 input connector.
Adjust VC-5 (C IN) on PCB T-3153 for a 30 pF indication.
3-8-10 CH-3 Attenuator Compensation
With conditions set as in Paragraph 3-8-9, reset the
SOURCE switch to 2 V/DIV. Connect a square-wave generator
to the CH-3 input connector. Set the generator controls for 10
Vp.p output at 1000 Hz.
Adjust VC-3 (CC) on PCB T-3153 for a correctly
compensated square- wave, per Figure 3-3.
3-8-11 CH-3 Attenuator Input Capacitance Adjustment
With conditions set as in Paragraph 3-8-10, remove the
square-wave generator and connect a capacitance meter to the
CH-3 input connector. Adjust VC-3 (C-l) for 30pF meter
indication.
3-8-12 CH-3 Gain Adjustment
With conditions set as in Paragraph 3-8-11, remove the
capacitance meter and connect an amplitude calibrator to the
CH-3 input connector. Set the calibrator controls for 1 Vp-p
output at 1000 Hz. Adjust VR-26 on PCB T-3155 for 5 major
divisions of vertical deflection on the CRT screen.
3-8-13 CH-1 Output Level Adjustment
Return the oscilloscope to the initial setup conditions. (See
Paragraph 3-1.) Connect the CH-1 OUTPUT connector to a test
oscilloscope having a 50-ohm feedthrough termination on its
input. Set the test oscilloscope's input attenuator at 20 mV/div.
Connect an amplitude calibrator adjusted for an output level of
100 mVp-p at 1000 Hz to.the CH-1 input connector of the LBO-
516.Adjust the CH-1 VARIABLE control for 4 major divisions
of vertical deflection on the LBO-516, then adjust VR- 1 on
PCB T-3155 for 4 divisions of vertical deflection on the test
oscilloscope.
Set the CH-1 AC/GND/DC switch to GND, and the CH-1
VARIABLE control to CAL'D. Make sure the test oscilloscope
is DC coupled and its ground reference is known. Adjust VR-2
on PCB T-3155 for a 0 VDC output as indicated on the test
oscilloscope.
3-8-14 CH-I/CH-2 HF Pulse Response Adjustment
Return the oscilloscope to the initial setup conditions. (See
32
Paragraph 3-1.) Set the CH-1 VOLTS/DIV switch to 5 mV, the
A TIME/DIV switch to 2/aS, the B TIME/DIV switch to .2 PS,
and press the INTEN BY B HORIZ DISPLAY pushbutton.
Connect a square-wave generator to the CH-1 input conneetor, and set the generator for 25 mVp-p output at 100 kHz.
Adjust the DLY TIME MULT control so the B (intensified)
trace is positioned over a leading edge of the displayed square
wave. Press the B HORIZ DISPLAY pushbutton, and adjust
VC-21 on PCB T-3155 and VC-1, VR-1, VC-2, VR-2, and VC3 on PCB T-3156 for minimum observed overshoot and ringing.
This can be checked by setting the CH-1 VOLTS/ DIV switch to
20 mV and pulling the CH-1 X10 MAG knob.
Cheek that the overshoot and ringing is less than 3% at all
positions of the CH-1 VOLTS/DIV switch. In each case the
generator output level should be adjusted for 5 major divisions
of vertical deflection.
Repeat the above procedure for CH-2. The corresponding
adjustment parts for CH-2 are VC-11 and VC- 12 on PCB T3155, and VC-13 on PCB T-3154.
3-8-15 CH-1/CH-2 Frequency Response Check
Return the oscilloscope to the initial setup conditions. (See
Paragraph 3-1.) Make sure the X10 MAG switches are pushed
in. Set the VOLTS/DIV controls to 5 mV, and the A TIME/DIV
switch to 2PS.
Connect a sine-wave generator to the CH-1 input connector, making sure the feedthrough termination appropriate for the
generator is attached to the CH- 1 input connector. Adjust the
generator for an output level of 40 mVp-p at 1 MHz; monitor the
frequency with a frequency counter.
Increase the frequency until the display indicates 5.6 major
divisions of vertical amplitude. This is the -3 dB point. The
counter should indicate a frequency of over 100 MHz. Repeat
the applicable adjustments in Paragraph 3-8-14 if it does not.
Move the generator to the CH-2 input connector, and press
the CH-2 V MODE pushbutton. Set the SOURCE switch at CH2, and repeat the above procedure for channel 2.
3-8-16 CH-1 Output Pulse Response
With conditions set as in Paragraph 3-8-13, set the CH-1
VOLTS/DIV switch of LBO-516 and that of the test oscilloscope to 5 mV/div.
Connect a square-wave generator adjusted for an output
frequency of I00 kHz to the CH-1 input connector. Adjust the
generator output level for 4 divisions of vertical deflection on
the test oscilloscope. Then, adjust VC- 1 and VC-2 on PCB T3155, and VC-3 on PCB T-3154 for less than 7% overshoot at
the leading and trailing edges of the waveform displayed on the
test oscilloscope.
3-8-17 CIt-1 & CH-2 Xl0 Magnifier Bandwidth Check
Return the oscilloscope to the initial setup conditions.(See
Paragraph 3-1.) Set the A TIME/DIV switch to 2PS, and pull the
CH-1 and CH-2 X10 MAG switch knobs.
Connect a sine-wave generator to the CH-1 input connector, and adjust it for 8 divisions deflection at 1 MHz. Monitor
the generator frequency with a frequency counter. Increase the
generator frequency until the displayed amplitude decreases to
5.6 divisions. This is the -3 dB point. The counter should
indicate a frequency of over 5 MHz.
Move the generator to the CH-2 input Connector, and press
the CH-2 V MODE pushbutton. Set the SOURCE switch at CH2, and repeat the above procedure for CH-2.
3-8-18 Vertical POSITION Control Centering
Return the oscilloscope to the initial setup conditions. (See
Paragraph 3-1.) Press the ALT V MODE pushbutton, and pull
the PULL TRIPLE control knob. Make sure the CH-1, CH-2,
and CH-3 vertical POSITION control knobs are set with their
index marks pointing straight up.
Adjust VR-22 on PCB T-3155 to position the CH-1 trace
on the center horizontal graticule line. Adjust VR-24 on PCB T3155 to position the CH-2 trace on the center horizontal
graticule line. Adjust VR-25 to position the CH-3 trace on the
center horizontal graticule line.
3-8-19 ADD Balance Adjustment
With conditions set as in Paragraph 3-8-18, push in the
ADD V MODE pushbutton. Adjust VR-27 on PCB T-3155 to
position the trace on the center horizontal graticule line.
3-9 TRIGGER CIRCUITRY ADJUSTMENTS
3-9-1 Trigger Balance and Centering Adjustments
Return the oscilloscope to the initial setup conditions. (See
Paragraph 3-1.) Set the CH-1 AC/GND/DC switch to AC, the
COUPLING switch to DC, and the A TIME/DIV switch to .2
mS.
Connect a sine-wave generator set for 1.2 Vp-p output at
1000 Hz to the CH-1 input connector. Make sure the LEVEL
control is centered (index mark up), and center the displayed
sine wave by means of the CH-1 vertical POSITION control so
the waveform extends from 3 major divisions above to 3 major
divisions below the center horizontal graticule line. Adjust the
horizontal POSITION control so the sweep starts on the first
vertical graticule line. Adjust VR-21 on PCB T-3153 for
symmetrical trigger points (above and below the center
horizontal graticule line) when the SLOPE switch is changed
from + to -. (See Figure 3-4.)
Adjust VR-32 on PCB T-3153 until the trigger point of the
displayed sine wave starts on the center horizontal graticule line
when the SLOPE switch is changed from + to -.
Reduce the output of the generator so the displayed sine
wave's p-p amplitude is only 0.4 (2 minor) divisions. Then fine
adjust VR-I and VR-12 on PCB T-3153 for a stable display in
each position of the SLOPE switch.
3-9-2 Trigger Balance Adjustments for Multitrace Modes
Return the oscilloscope to the initial setup conditions (See
Paragraph 3-1.) Set the AC/GND/DC switches to GND, press
the ALT V MODE pushbutton, pull the PULL TRIPLE control
knob, and set the SOURCE switch to CH-2.
Turn the CH-1 vertical POSITION control fully counterclockwise, and center the CH-3 trace with the CH-3 vertical
POSITION control. Change the COUPLING switch to DC and
adjust VR-22 on PCB T-3153 to recenter the trace.
Set the SOURCE switch to .2 V/DIV and adjust VR-23 on
PCB T-3153 to recenter the trace. Reset the AC/GND/DC
switches to AC and recenter the trace if necessary.
Restore the COUPLING switch to AC and recenter the
trace with VR-31 on PCB T-3153.
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3-9-3 PRESET Trigger Adjustment
Return the oscilloscope to the initial setup conditions. (See
Paragraph 3-1.) Connect a sine-wave generator to the CH-1
input connector. Adjust the generator output for 2 minor divisions of vertical deflection at I000 Hz. Pull the HOLDOFF
control for PRESET trigger. Adjust VR-2 on PCB T-3159 until
the waveform is triggered and the TRIG'D lamp lights.
3-9-4 CH-3 Pulse Response Adjustment
Return the oscilloscope to the initial setup conditions. (See
Paragraph 3-1.) Press the ALT V MODE pushbutton, pull the
PULL TRIPLE control knob, set the COUPLING switch to DC,
and the SOURCE switch to.2 V/DIV. Center the CH-3 trace.
Connect a square-wave generator to the CH-3 input connector. Set the generator for 1 Vp-p output level at 100 kHZ.
Adjust VC-6 on PCB T-3153 and VC-23 on PCB T-3155 to
reduce overshoot and ringing to below 10%. Check the frequency response of CH-3 in the same manner as was done in
Paragraph 3-8-15.
3-9-5 Interred Trigger-Pulse Response Adjustment
Return the oscilloscope to the initial setup conditions. (See
Paragraph 3-1.) Set the VOLTS/DIV switches to 5 mV, the
COUPLING switch to DC, and press the ALT V MODE
pushbutton.
Connect a square-wave generator set for 25 mVp-p output
at I00 kHz to the CH-1 input connector. Adjust VC-I on PCB T3153 to minimize overshoot and ringing. Total overshoot and
ringing should be less than 10%.
Repeat the above procedure for channel 2, adjusting VC-2
on PCB T-3153.
3-10. X-Y MODE ADJUSTMENTS
3-10-1 Gain Adjustment
Return the oscilloscope to the initial setup conditions. (See
Paragraph 3-1.) Press the X-Y pushbutton.
Connect a square-wave generator set for 100mVp-p output
at 1000 Hz to the CH-1 (X IN) connector. Adjust VR-31 on
PCB T-3158 for 5 major divisions of separation between the two
dots displayed on the CRT screen. (Note: the position of the dots
will change when adjusting VR-31; this is normal.)
3-10-2 Balance Adjustment
With conditions set as in Paragraph 3-10-1, set both AC/
GND/DC switches to GND. Check that the horizontal POSITION and X FINE control knobs are set with their index marks
up, then adjust VR-32 on PCB T-3158 to center the dot
horizontally on the CRT screen.
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