Leader LBO-51MA User manual

LBO-51MA
DISPLAY
SERVICE MANUAL
********************************
NOTE
These servicing instructions are for use by
qualified personnel only. To avoid electrical
shock, do not perform any servicing other than
that contained in the service manual unless
you are qualified to do so.
********************************

CONTENTS
1. SPECIFICATIONS
2. TEST EQUIPMENT REQUIRED
3. CALIBRATION PROCEDURE
3.1 General
3.2 Initial Control Settings
3.3 Power Supply
3.4 Display
(1) Intensity Adjustment
(2) Focus Adjustment
3.5 Y-AXIS
(1) Bias Adjustment
(2) DC Balance Adjustment
(3) Sensitivity Adjustment
(4) Frequency Response Check
3.6 X-AXIS
(1) Bias Adjustment
(2) DC Balance Adjustment
(3) Sensitivity Adjustment
(4) Frequency Response Check
3.7 X-V PHASE adjustment
3.8 Z-AXIS
4. TROUBLESHOOTING PROCEDURE
4.1 Troubleshooting Aid-1
4.2 Troubleshooting Aid-2
4.3 Troubleshooting Aid-3
(1) Overall operation
(2) Y-AXIS
(3) X-AXIS
(4) Z-AXIS
5. ADJUSTMENT LOCATIONS
Right side view
Left side view
Page
3
4
5
5
5
5
6
6
6
6
6
6
7
7
7
7
7
8
8
8
8
10
10
10
11
11
12
12
12
13
13
14
6. PRINTED
T-2510
T-2511
T-2512
T-2513
CIRCUIT BOARD(Component side
Main board
X, Y pre-amplifier board
CRT control board
X, Y control board
-1-
LBO-51MA
view) 15
15
16
17
17

7. BLOCK DIAGRAM
8. SCHEMATIC DIAGRAM
(1/4) Power supply
(2/4) CRT and Z-AXIS amplifier
(3/4) Xt Y pre-amplifier
(4/4) Xt Y final amplifier
9. PARTS LIST
10. CABINET REMOVAL
-2-
LBO-51MA
Page
18
19
19
20
21
22
23
27

1. SPECIFICATIONS
Vt:rtical and lloriLonlal Amplifiers Phydca1 and Environmental Data
AC Coupled
Input Impedance •
RiJe Time
Phase Shift
Bandwidth
DC Coupled
Type oC CRT phOlphor
CRT int.emal gnticu1e( or
graphica IUpplied by uaer)
X-Y axil aeruitivity (al-
tenuated)
X-Y-Z input terminationa
Z-axis input polarity
Z-axis TTL input level
aenaitivi ty (+6 V)
Blue CRT mter plau
(without gnticule)
Inatruction manual
FUle
117 V ±lO%, 60/60 Hz
(Accomodates lOO, 220,
240 V .upplie. by power
traJuCormer tap ae1ection)
26 watla (max1mum)
8.4 in. (216 mm) W X
6.126 in. (132 mm) H X
17.6 in. (450 mm) D
14.3 Iba (6.6 ~)
odog. C to 60 deg. C
(32 deg. F to 122 dog. F)
-20 dog. C to 70 de~ C
(-4 dOj(. F to 162 deg. F)
Accesaories Furni.lbed
Available Optlona
Power Consumption
Dlmenaioru
Power Requiremenla
Storage Temperature
Weight
Operating Temperature
DC to 3 MHz, -3 dB,
5 div ref
2 Hz to 3 MHz, -3 dB,
5 div ref
Less than 120 nS
Leu than 3 dog. at 1
MHz, 8 di v ref
Within 6%
AC or DC, .elected by
inumal nritchini (aup-
plied in DC polition)
1 megohm ±2%, lea than
60 pF
Maximum Input Voltage 100 V (DC +AC peak)
Polarity InUmally.witchable
Z-AxiI (lntenlity)
Sensitivity +1V
Linearity
Input Coupling
Denection Sensitivity 60 m VIdiy, adju.lable
Crom 60 mVIdly to 160
mVIdiv (via Cront-panel
screwdrivor adjuatment)
Accuracy +3%
Band wid th
Rise Time
Input Impedance
DC to 4 MHz
Less than 90 nS
1 megohm ±2%, lea than
60pF
Maximum Input Vollage 100 V (DC + AC peak)
• Standud configuration
CRT Dbplay
Di.play. Area 8cm H X 10 cm W
Graticule
Brightness
Spot Size
Accelerating Voltage
Phosphor •
Removable, 8 div H X 10
diy W (1 div - 10 mm)
25 CL(measured with 60
Hz reCresh raU and 100-
line raster)
0.26 mm at 0.611A beam
current
7kV/2 kV (slabilized)
P3l
-3-

2. TEST EQUIPMENT REQUIRED
The following test equipment is required for calibration and
servicing of the Model LBO-51MA. The suggested specifications
are the minimum necessary for proper calibration of this
instrument.
Test Equipment
Multimeter
- Oscilloscope
- Sine Wave Generator
- Amplitude Calibrator
Mi.nimum Spec
o - 200V
Accuracy <1%
*LEADER Model LDM-853A
High voltage probe
*LEADER Model LP-6
10mV sensi~ivity
50MHz bandwidth
Low capacitance probe
*LEADER Model LBO-526
10Hz - 4MHz
200mV Square wave
*LEADER Model LOC-7005
-4-
LBO-51MA

3. CALIBRATION PROCEDURE
3.1 General
Calibration should be performed after a 30 minute warm-up
period. It should also be confirmed that the unit is
connected to the rated power line voltage.
All adjustments should be completed in the given order,
because some adjustments interact with others.
During the adjustment procedure, remove the case only when
necessary and replace immediately after making an
adjustment. This will maintain all circuits at constant
operating temperature.
Take utmost precaution to come into contact with the high
voltage circuits!
3.2 Initial Control Settings
The initial control settings to be used for each check and
adjustment are listed below. Any variations from these
settings are stated in the applicable procedure.
Y-AXIS
POSITION
GAIN
X-AXIS
POSITION
GAIN
INTEN
FOCUS
Center
Fully clockwise
Center
Fully clockwise
As desired
Best focused display
3.3 Power Supply
Connect the DC voltmeter between test point on the pc
board(T-2510) and chassis.
Adjust as required, using the adjustment shown in
Table 3-1.
Test point
TP1
TP2
TP3
TP4
Voltage
+150V
-15V
+15V
-1900V
Tolerance
+140V to +160V
-14.1V to -15.9V
+14.4V to +15.6V
Adjustment
VR2
Table 3-1
-5-
LBO-51MA

3.4
( 1) D:isplay
Intensity Adjustment
Set: INTEN Midway between 10 and 11 o'clock
position
- Adjust VRl(T-2510) so the trace is just visible.
(2) Focus Adjustment
Set: INTEN
FOCUS 1 o'clock position
Center
Connect the sine wave generator to X and Y INPUT connectors
and set the frequency to 1kHz, output level for 8 x 8
divisions display.
Adjust VR3(T-2510) for optimum trace sharpness.
Adjust ASTIG control and VR5(T-2510) alternately to obtain
a best focused display.
3.5
(1) Y- AXIS
Bias Adjustment
Connect the DC voltmeter between pin 1 and 3 of P12(T-
2510) .
Set the Y POSITION control for a meter reading of ~V.
Remove the DC voltmeter, then reconnect it between either
pin 1 or 3 of the P12 and chassis.
Adjust VRl1(T-2510) for a meter reading of +90V.
(2) DC Balance Adjustment
Set: Y-AXIS
GAIN Fully counterclockwise
- Position the trace to the center horizontal graticule line
using the Y-AXIS POSITION control.
Rotate the GAIN control to fully clockwise
If the spot moves 1 division or more, adjust VRl(T-2511)
for minimum trace shift between both extremes of the
POSITION control settings.
-6--
LBO-51MA

(3) Sensitivity Adjustment
- Set: Y-AXIS
GAIN Fully clockwise
Connect the amplitude calibrator to Y-AXIS INPUT connector
and set the output level to 200mVp-p.
Adjust VR2(T-2511) for 4 divisions display.
(4) Frequency Response Check
Set: Y-AXIS
GAIN Fully clockwise
Connect the sine wave generator to Y-AXIS INPUT connector
via suitable terminator and set the frequency to 1kHz,
output level for 5 divisions display.
Increase the frequency until the trace length decreases to
3.5 division and observe the generator frequency is greater
than 3MHz.
3.6
(1) X-AXIS
Bias Adjustment
Connect the DC voltmeter between pin 1 and 3 of Pl1(T-
2510) .
Set the X POSITION control for a meter reading of ~V.
Remove the DC voltmeter, then reconnect it between either
pin 1 or 3 of the P11 and chassis.
Adjust VR12(T-2510) for a meter reading of +90V.
( 2 ) DC Balance Adjustment
Set: X-AXIS
GAIN Fully counterclockwise
Position the trace to the center vertical graticule line
using the X-AXIS POSITION control.
Rotate the GAIN control to fully clockwise
If the spot moves 1 division or more, adjust VR3(T-2511)
for minimum trace shift between both extremes of the
POSITION control settings.
-7-
LBO-51MA

(3) Sensitivity Adjustment
- Set: X-AXIS
GAIN Fully clockwise
Connect the amplitude calibrator to X-AXIS INPUT connector
and set the output level to 200mVp-p.
Adjust VR4(T-2511) for 4 divisions display.
(4) Frequency Response Check
Set: X-AXIS
GAIN Fully clockwise
Connect the sine wave generator to X-AXIS INPUT connector
via suitable terminator and set the frequency to 1kHz,
output level for 5 divisions display.
Increase the frequency until the trace length decreases to
3.5 division and observe the generator frequency is greater
than 3MHz.
3.7 X-Y Phase Adjustment
- Set: X-AXIS
GAIN
Y-AXIS
GAIN
Fully clockwise
Fully clockwise
Connect the sine wave generator to X and Y INPUT connectors
with matching-length cables and set the frequency to 1MHz,
output level for 8 x 8 divisions display.
Adjust VC2(T-2511) to eliminate any double-trace effect
visible in the mid-portion of the display.
l
1
3.8 Z-AXIS
Connect the test oscilloscope to TP5(T-2510) with DC
coupled input mode and set the vertical sensitivity to
O.5VjDIV. Use well-compensated low capacitance probe.
Connect the sine wave generator to Z INPUT connector and
set the frequency to 1kHz, output level for 4 divisions
(20Vp-p) display on the test oscilloscope.
-8-
LBO-51MA

- Adjust INTENcontrol for a DC level as shown in Figure 3-1.
- Increase the frequency until the sine wave amplitude
decreases to 2.8 division(14Vp-p) and observe the generator
frequency is greater than 4MHz.
+60V
d •• +40V
OV
Figure 3-1
-9-
LBO-51MA

4. TROUBLESHOOTING PROCEDURE
4.1 Troubleshooting Aid-1
Confirm that the any equipment used with the LBO-51MA is
operating correctly.
Check all control settings, because an incorrect setting can
make a good unit appear defective. If there is any question
about the function, refer to the INSTRUCTION MANUAL for a
correct operation.
Check all circuit for visual defects such as broken
component, loose connection of a connector, open wire, poor
soldering etc.
Some troubles can be solved with proper adjustment.
Check the voltage and waveform as shown in the Schematic
Diagram to locate the defective circuit. Start with the
power supply.
Typical voltage and waveform are obtained under the same
conditions as "3.2 Initial Control Settings"
Take utmost precaution to come into contact with the high
voltage circuits!
4.2 Troubleshooting Aid-2
The oscilloscope consists of three major sections which are
the high voltage power supply, Y-AXIS amplifier and X-AXIS
amplifier. In general, if one of these is defective, the
trace will not. appear on the CRT. Therefore, the most
effective procedure is to check these three sections one by
one.
The high voltage power supply produces +5kV/-2kVdc to
accelerate the electron beam from the electron gun to the
face plate of the CRT. If the +5kV/-2kVdc is too low, the
spot will either not appear or be dim.
The Y-AXIS and X-AXIS amplifier consist of a pre-amplifier
and a final amplifier, all of which are DC coupled balanced
circuits. If some portion of the Y-AXIS amplifier becomes
unbalanced by a defective component, the spot will be
deflected off the face of the CRT. Therefore, it is best
to check the state of amplifier balancing when the spot does
not appear on the CRT.
-10-
LBO-51MA

+150V;
1
4.3 Troubleshooting Aid-3
(1) Overall operation is not satisfactory or no spot appears.
a. Check the power supply voltage within tolerance according
to Table 3-1.
Yes; Proceed to lib".
No; Check and troubleshoot on following points.
Line fuse
Secondary voltage of the power transformer
+15V; D3, IC3(T-2510) and associated circuit.
-15V; +15V line, D2, Q4-6, IC2(T-2510) and
associated circuit.
-15V line, D1, Q1-3, IC1(T-2510) and
associated circuit.
-1900V; Check the waveform at collector of Q7(T-2510)
for 40kHz sine wave and troubleshoot the
associpted circuit. Check F1 of +22V line.
Adjust HV ADJ(VR2 T-2510) if necessary.
b. Connect pin 1 and 3 of P12(T-2510) with short clip lead for
balancing check of Y-AXIS amplifier. Spot appears.
Yes; Connect pin 1 and 3 of P10(T-2510) with short clip
lead. Spot appears.
Yes- Troubleshoot Pre-amplifier.
No- Troubleshoot Final amplifier. Adjust Y-axis
bias(VR11 T-2510) if necessary. Refer to
paragraph 3.5 (1).
No: Proceed to "c".
c. Connect pin 1 and 3 of P11(T-2510) with short clip lead for
balancing check of X-AXIS amplifier. Spot appears.
Yes; Connect pin 9 and 11 of P10(T-2510) with short clip
lead. Spot appears.
Yes- Troubleshoot Pre-amplifier.
No- Troubleshoot Final amplifier. Adjust Y-axis
bias(VR12 T-2510) if necessary. Refer to
paragraph 3.6(1).
No; Troubleshoot CRT control circuit. Adjust CRT bias(VR1
T-2510) if necessary. Refer to paragraph 3.4 (1).
-11-
LBO-51MA

(2) No Y-AXIS deflection or low sensitivity
Connect the amplitude calibrator to Y-AXIS INPUT connector
and set the output voltage to 200mVp-p. Set the controls
as paragraph "3.2 Initial Control Settings".
Trace the waveform from -the input to output stage by using
the test oscilloscope to locate the defective circuit.
a. Check waveform at pin 1 of PIO(T-2510).
Yes: Troubleshoot Y-axis final amplifier(Q41-47 T-2510).
No: Troubleshoot Pre-amplifier. Adjust sensitivity (VR2
T-2511) if necessary. Refer to paragraph 3.5 (3).
(3) No X-AXIS deflection or low sensitivity
Connect the amplitude calibrator to X-AXIS INPUT connector
and set the output voltage to 200mVp-p. Set the controls
as paragraph "3.2 Initial Control Settings".
Trace the waveform from the input to output stage by using
the test oscilloscope to locate the defective circuit.
a. Check waveform at pin 9 of PIO(T-2510).
Yes: Troubleshoot Y-axis final amplifier(Q48-54 T-2510).
No: Troubleshoot Pre-amplifier. Adjust sensitivity (VR4
T-2511) if necessary. Refer to paragraph 3.6 (3).
(4) Z-AXIS malfunction
Connect the sine wave generator to Z INPUT connector and
set the frequency to 1kHz, output voltage to IVp-p'.
Check the waveform at TP5 for 24Vp-p sine wave.
Yes: Troubleshoot CRT control circuit
No: Troubleshoot Z-AXIS amplifier
-12-
LBO-51MA

- RIGHT SIDE VIEW -
X AXIS
BIAS
+ OV
P11 VR12 V1
-
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-- T-2510
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- LEFT SIDE VIEW -
--Y-AXIS--
T-2511
-- X-AXIS--
T-251J

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