Text preview for : DIAMOND PRO 2070SB + NEC Multisync FP2141SB.pdf part of Mitsubishi DP2070SB This is the Full service manual for the Mits DP2070SB but can also be used for the NEC FP2141SB
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PART NO. 599910644
SERVICE MANUAL
CRT DISPLAY
DPro2070SB / DPro2070SB-BK
(C22BW711)
Southern Hemisphere Version
The First Edition
NEC-MITSUBISHI ELECTRIC VISUAL SYSTEMS CORPORATION
FEBRUARY 2003
Contents
1. Circuit description ............................................................................................................................ 1-1
1.1 Power block ............................................................................................................................ 1-1
1.1.1 Outline ........................................................................................................................... 1-1
1.1.2 Rectifying circuit and higher harmonics suppression (active filter)
circuit ............................................................................................................................. 1-1
1.1.3 Sub power circuit ......................................................................................................... 1-2
1.1.4 Main power circuit ........................................................................................................ 1-2
1.1.5 Demagnetizing circuit .................................................................................................. 1-2
1.1.6 Power management circuit ......................................................................................... 1-2
1.2 Deflection processor block ................................................................................................... 1-3
1.2.1 Deflection processor (IC601) ..................................................................................... 1-3
1.2.2 Pressure-reduction type horizontal deflection power circuit (IC5C0) .................. 1-3
1.2.3 Horizontal width control circuit .................................................................................. 1-3
1.2.4 Vertical deflection circuit ............................................................................................ 1-3
1.2.4.1 Sawtooth waveform generation, vertical size/position control, and
linearity control circuit .................................................................................. 1-3
1.2.4.2 Vertical output amplification circuit ............................................................ 1-4
1.2.5 High voltage block ....................................................................................................... 1-4
1.2.6 DBF (Dynamic Beam Focus) circuit .......................................................................... 1-5
1.3 Video block ............................................................................................................................. 1-6
1.3.1 Video signal amplifier circuit ...................................................................................... 1-6
1.3.1.1 Video clamp .................................................................................................... 1-6
1.3.1.2 Video blanking ............................................................................................... 1-6
1.3.1.3 Video mixing/amplifying ............................................................................... 1-6
1.3.1.4 Control of contrast and white balance ....................................................... 1-6
1.3.2 Cut-off control circuit ................................................................................................... 1-7
1.3.2.1 Control of brightness .................................................................................... 1-7
1.3.2.2 Control of BIAS .............................................................................................. 1-7
1.3.3 OSM (On Screen Manager) ........................................................................................ 1-7
1.3.4 2 Input change circuit .................................................................................................. 1-8
1.3.5 Sync on Green circuit .................................................................................................. 1-8
1.3.6 Asset circuit .................................................................................................................. 1-8
1.3.7 AUTO-SIZE function .................................................................................................... 1-8
1.3.8 SB MODE (Super Bright Mode) function .................................................................. 1-8
1.3.8.1 Adjustment item/operating function in selecting SB Mode ..................... 1-8
1.3.8.2 Circuit (cathode) operation in selecting SB Mode [Window pattern] .... 1-9
1.3.8.3 SB Mode setting data and control method ................................................ 1-9
1.3.9 CONSTANT BRIGHTNESS function ....................................................................... 1-10
iii
1.4 CRT compensation block .................................................................................................. 1-10
1.4.1 Earth magnetism cancel circuit .............................................................................. 1-10
1.4.2 Rotation circuit ......................................................................................................... 1-11
1.4.3 East-west horizontal magnetic field vertical position
canceling function ................................................................................................... 1-11
1.4.4 Corner purity circuit ................................................................................................. 1-11
1.4.4.1 Corner purity circuit operation .................................................................. 1-12
1.4.5 Vertical magnetic field landing cancel circuit ...................................................... 1-12
1.4.6 Digital dynamic convergence clear (DDCC) circuit ............................................ 1-12
1.4.6.1 Production of compensation current waveform ..................................... 1-13
1.4.6.2 Waveform, and operation on the picture ................................................ 1-13
1.4.6.3 Adjustment method .................................................................................... 1-14
1.4.6.4 Block diagram ............................................................................................. 1-14
1.4.7 East-west horizontal convergence canceling function ....................................... 1-19
1.5 USB circuit ........................................................................................................................... 1-19
1.5.1 Outline ....................................................................................................................... 1-19
1.5.2 USB downstream power supply ............................................................................. 1-19
1.5.3 HUB controller power output .................................................................................. 1-19
1.5.4 USB power on reset ................................................................................................ 1-19
1.6 Control block ....................................................................................................................... 1-20
1.6.1 Function of control circuit ....................................................................................... 1-20
1.6.2 Auto-tracking process ............................................................................................. 1-20
1.6.3 EEPROM ................................................................................................................... 1-20
1.6.4 On-Screen-Manager (OSM) controller .................................................................. 1-20
1.6.5 Heater voltage control ............................................................................................. 1-20
1.6.6 Protection circuit operation .................................................................................... 1-20
1.6.6.1 X-ray protector ............................................................................................ 1-20
1.6.6.2 High voltage data error detection ............................................................ 1-21
1.6.6.3 Beam current protector .............................................................................. 1-21
1.6.6.4 Power-On Indicator (LED) flickering pattern
in each protector operating ...................................................................... 1-21
1.6.6.5 Operating time ............................................................................................ 1-21
1.6.6.6 The DDC communication .......................................................................... 1-21
1.6.6.7 Microcomputer pin assignment ................................................................ 1-22
1.7 X-ray protection circuit and safety protection circuit ................................................... 1-23
1.7.1 X-ray protection circuit ............................................................................................ 1-23
1.7.2 Beam current protection circuit .............................................................................. 1-23
1.7.3 IC701 overcurrent protection circuit ..................................................................... 1-23
1.7.4 IC701 overload protection circuit .......................................................................... 1-23
1.7.5 IC902 overcurrent protection circuit ..................................................................... 1-23
iv
1.7.6 Short-circuit protection circuit on secondary power side .................................... 1-23
1.7.7 Overvoltage protection circuit .................................................................................. 1-23
1.8 Adjustment ............................................................................................................................ 1-24
1.8.1 Adjustment mode ....................................................................................................... 1-24
1.8.2 User mode (Normal mode) ....................................................................................... 1-24
1.8.3 Factory mode .............................................................................................................. 1-27
1.8.3.1 How to entering to Factory mode .............................................................. 1-27
1.8.3.2 How to cancel Factory mode ..................................................................... 1-27
1.8.3.3 How to enter FACTORY-HV mode ............................................................ 1-27
2. Adjustment procedure ................................................................................................................... 2-1
2.1 Measuring instruments ....................................................................................................... 2-1
2.2 Preparatory inspections ..................................................................................................... 2-1
2.3 Names of each monitor part .............................................................................................. 2-2
2.3.1 Configuration of front control panel ....................................................................... 2-2
2.3.2 Configuration of rear input connector (signal input) ........................................... 2-2
2.3.3 OSM display matrix .................................................................................................. 2-3
2.3.3.1 User mode ................................................................................................... 2-3
2.3.3.2 Factory mode .............................................................................................. 2-4
2.4 Adjustment ........................................................................................................................... 2-7
2.4.1 How to select the factory adjustment (FACTORY) mode ................................... 2-7
2.4.1.1 Selecting with front panel switches ......................................................... 2-7
2.4.2 Adjustments before aging ........................................................................................ 2-7
2.4.2.1 Adjusting the high voltage and high voltage protector ......................... 2-7
2.4.2.2 FOCUS adjustment (Rough adjustment) ................................................ 2-8
2.4.2.3 Shock test .................................................................................................... 2-8
2.4.2.4 Preadjustment before aging ...................................................................... 2-8
2.4.2.5 Adjusting the landing (ITC/4 corner purity adjustment) ........................ 2-9
2.4.3 Adjusting the picture size, position and distortion, DBF amplitude and phase 2-9
2.4.3.1 Adjusting the picture inclination ............................................................... 2-9
2.4.3.2 Adjusting the back raster position ........................................................... 2-9
2.4.3.3 Adjusting the left/right distortion, picture width, picture position (LEFT/
RIGHT) and vertical linearity (all preset) ................................................ 2-10
2.4.3.4 Adjusting the DBF amplitude and phase ................................................ 2-10
2.4.4 Adjusting the cut off ................................................................................................. 2-11
2.4.4.1 Adjusting BTCEN (BRIGHT-CENT), BTMAX (BRIGHT-MAX) and BS1
(BIAS-H) ....................................................................................................... 2-11
2.4.4.2 Adjusting BS2 (BIAS-M) / BS3 (BIAS-L) .................................................. 2-12
2.4.5 Setting CONSTANT BRIGHTNESS circuit (Factory mode) ................................ 2-13
2.4.5.1 Reading beam current default data ......................................................... 2-13
2.4.5.2 Confirming CONSTANT BRIGHTNESS function ................................... 2-13
v
2.4.6 Adjusting the RGB drive signal ............................................................................... 2-13
2.4.6.1 Adjusting GN1 (GAIN-H) (adjustment of 9300K) .................................. 2-13
2.4.6.2 Adjusting ABL .............................................................................................. 2-15
2.4.7 Adjusting the focus ................................................................................................... 2-15
2.4.8 Adjusting the convergence ...................................................................................... 2-16
2.4.8.1 Adjusting with ITC ...................................................................................... 2-16
2.4.8.2 Adjusting DDCP .......................................................................................... 2-18
2.4.9 Default settings (With factory mode) ..................................................................... 2-23
2.5 Inspections (In normal mode) ............................................................................................ 2-24
2.5.1 Electrical performance ............................................................................................. 2-24
2.5.1.1 Withstand voltage ....................................................................................... 2-24
2.5.1.2 Grounding conductivity check .................................................................. 2-24
2.5.1.3 Degaussing coil operation ......................................................................... 2-24
2.5.1.4 IPM OFF MODE function operation (Set the AC power input to 230V) ....... 2-24
2.5.1.5 Confirming the GLOBAL SYNC (CORNER-Purity) function ................. 2-25
2.5.1.6 Focus, picture performance ...................................................................... 2-25
2.5.1.7 Misconvergence .......................................................................................... 2-25
2.5.1.8 Picture distortion ........................................................................................ 2-26
2.5.1.9 Linearity ....................................................................................................... 2-28
2.5.1.10 Adjustment value list ................................................................................ 2-29
2.5.1.11 Confirming EDGELOCK and SYNC GREEN ........................................ 2-30
2.5.1.12 Checking the functions during Composite Sync input ........................ 2-30
2.5.1.13 Confirming the reset operation .............................................................. 2-30
2.5.1.14 Confirming the full white luminance/color coordination ...................... 2-30
2.5.1.15 Confirming CONVERGENCE compensation function ......................... 2-30
2.5.1.16 Confirming ROTATION compensation function ................................... 2-31
2.5.1.17 Luminance/color coordination uniformity .............................................. 2-31
2.5.1.18 Confirming the color tracking ................................................................. 2-31
2.5.1.19 CRT installation position ......................................................................... 2-31
2.5.1.20 Confirming SB MODE operation ............................................................ 2-31
2.5.1.21 Confirming AUTO-ADJUST operation ................................................... 2-32
2.5.1.22 Confirming USB ........................................................................................ 2-32
2.5.1.23 Others ......................................................................................................... 2-32
2.6 DDC function, check of asset management .................................................................... 2-33
2.6.1 DDC write data contents .......................................................................................... 2-34
2.6.2 Self-diagnosis shipment setting ............................................................................. 2-35
2.7 Default inspection ............................................................................................................... 2-35
2.7.1 Default setting of switches ...................................................................................... 2-35
2.7.2 Default setting of OSM ............................................................................................. 2-35
2.7.3 Checking the labels .................................................................................................. 2-35
vi
2.7.4 Packaging .................................................................................................................. 2-35
2.8 Degaussing with handy-demagnetizer ............................................................................. 2-36
2.8.1 General precautions ................................................................................................. 2-36
2.8.2 How to hold and use the handy-demagnetizer ................................................... 2-36
2.9 Caution ................................................................................................................................. 2-36
2.10 Timing chart ....................................................................................................................... 2-37
2.11 Adjustment timing ............................................................................................................. 2-38
3. Trouble shooting
4. Wave form
5. Schematic diagram
6. Removal instruction sheet
7. Exploded view / Packing view
Serial number information
Specification
User's guide
All parts list
vii
1. Circuit description
1. 1 Power block
1.1.1 Outline
The power block is compatible with the business electric power, 100 to 120VAC/220 to 240VAC (50/60Hz).
The active filter circuit is adopted to suppress the higher harmonic current.
The circuit block is composed of two switching regulators, the main power which is the configuration used
the flyback converter system of pseudo resonance operation and the sub power which is the configuration
used PWM (pulse wise modulation) system.
The output on the secondary side is shown in Table 1.
Power block Output voltage Mai load
+215V H. deflection circuit, Cut-off circuit
+80V Video circuit, DBF circuit, High voltage circuit
+15V H. deflection circuit, Rotation circuit
Main power side
-15V Convergence circuit, Corner purity circuit
+12V Video circuit, H. deflection circuit
+8V Heater
+5V Microcomputer (MPU)
Sub power side
P-OFF+5V VIDEO circuit
Table 1
1.1.2 Rectifying circuit and higher harmonics suppression (active filter) circuit
The AC input voltage is rectified in the full wave mode with the diode bridge in D901 and input to pin 5 of
L903. The voltage of both end of C911 is the DC voltage approx. 390VDC boosted with the booster
circuit (active filter circuit) composed of IC901, Q901, L903 and D902. The active filter circuit compares
the voltage input to pin 1, pin 3 and pin 4 of IC901 and controls Q901 ON/OFF period so that the current
flows to L903 be sine-waved. The AC input current is sine-waved in the same phase with the input
voltage so as to improve the power factor, and the harmonic current is controlled consequently.
AC D933 To Main power
L902
and sub power
D901
D902
R904 L903 R913 +
C906 C911
R905
AC
R906 R914
L905
R911
R907 R915
Q901
R912
R917
R909
R908
IC901 R937
From Sub power C910
R910
Vcc
C907
C908
Fig. 1
1.1.3 Sub power circuit
When the power switch is turned ON, the rectified and smoothed DC voltage (AC voltage x 2) is
supplied to pin 5 of IC903, and is charged to C930 through pin 1. When pin 1 reaches 5.7V, oscillation is
started in IC903, and the built-in output FET is put into operation to add the pulse voltage between pin 5
and pin 3 on the primary side of T902. The flyback voltage in proportion to the voltage on the primary
side is generated on the secondary side, then the DC voltage is generated with the half-wave rectifier
circuit composed of D971 and C971. The DC voltage generated at the secondary side is monitored by
IC922 through R976, R977 and R978. This information detected at IC922 is fed back to pin 1 of IC903
via PC902, and the ON period of output FET internal IC903 is controlled to keep the DC voltage on the
secondary side constantly. The flyback voltage in proportion to the voltage on the primary side is also
generated at pin 2 of T902. The pulse voltage generated at pin 2 of T902 is converted to the DC voltage
at D932 and C931, and supplied to pin 8 of IC901 and pin 4 of IC902 via Q902.
1.1.4 Main power circuit
When the P-SUS signal from microcomputer is turned to HI, Q902 is turned to ON, and the voltage approx.
+18V is supplied to pin 4 (Vcc terminal) of IC902 from pin 2 of T902.
When the voltage of pin 4 of IC902 reaches approx. +16V, oscillation is started in the circuit, and the
built-in output FET is put into operation to add the pulse voltage between pin 5 and pin 2 on the primary
side of T901. The flyback voltage generated at the secondary side in proportion to the one in the primary
side is rectified at D961, D963, D964, D965 and D967 and smoothed at C961, C963, C964, C965 and
C969 to generate the DC voltage. The DC voltage generated at the secondary side is monitored by
IC921 through R960, R961, R962 and R985. The information detected at IC921 is fed back to pin 1 of
IC902 via PC901, and the ON period of output FET internal IC902 is controlled to keep the DC voltage on
the secondary side constantly.
1.1.5 Demagnetizing circuit
When the power is turned ON or the manual demagnetizing function on OSM menu is set to ON, pin 47 of
IC102 on the main board is turned to HI, and Q950 and RL901 are also turned ON.
When RL901 is turned ON, the current flows to the demagnetizing coil, however, the demagnetizing
current gradually converges with the fever of TH902.
1.1.6 Power management circuit
This monitor carries the power management function. This function is effective only when being
connected with the personal computer carrying the power management function.
Mode H-SYNC V-SYNC State Display
NORMAL ON ON Displaying a picture Displaying a picture
OFF ON No picture
SUSPENSION ON OFF CRT heater is
No raster
OFF OFF decreased voltage
mode (approx. 1.5V)
The power consumption and the indication of Power-On Indicator for each mode are as follows.
Mode Power consumption Power-On Indicator
NORMAL 135W Green
SUSPEND 3W or less Orange
The control signal executes the power management function is output from microcomputer IC102. The
control signal is composed of two signals, SUSPEND and P-OFF. The operating state of each signal is
as follows.
Control signal name Pin of IC102 Normal Suspension
SUSPEND Pin 5 H L
P-OFF Pin 42 H L
1.2 Deflection processor block
1.2.1 Deflection processor (IC601)
Deflection processor IC601 horizontally compensates wise, position and distortion, and vertically controls
heights, position and linearity.
IC601 automatically tracks the frequency to output the appropriate horizontal/vertical drive pulse.
IC601 also outputs the horizontal parabola waveform for focus and the waveform for convergence
compensation.
1.2.2 Pressure-reduction type horizontal deflection power circuit (IC5C0)
IC5C0 compares the parabola waveform output from pin 64 of IC601 (this waveform controls the
horizontal width and distortion) with the sawtooth waveform (this waveform is synchronized with the
horizontal frequency) in order to output the +B drive pulse. The +B drive pulse output from pin 9 of IC5C0
will accumulate the 215V energy in T550 during Q5F1 ON period. During Q5F1 OFF period, the
accumulated energy will be released, and integrated by T550 and the S-shaped compensation capacitor.
The duty of this drive pulse depends on the DC level of the parabola waveform that is output from IC601.
1.2.3 Horizontal width control circuit
Q550 is controlled by the horizontal drive pulse that is output from IC601. When Q550 is ON, the energy
will be accumulated in the horizontal deflection yoke. When Q550 is OFF, the energy will flow into C550.
While repeating this operation, horizontal deflection will be carried out.
The collector pulse of Q550 will be subject to voltage division by C590 and C591, and the voltage-divided
pulse will be used for switching synchronization of the high-voltage control IC701 and also used as the
AFC pulse.
The duty of the +B drive pulse output from pin 9 of IC5C0 will be subject to change in order to control the
horizontal width. The parabola waveform output from IC601 is compared with the feedback waveform
output from T5C0 to obtain the comparison waveform, and this comparison waveform threshes the
sawtooth waveform inside IC5C0 in order to control the duty. If the duty is changed, the rectified voltage of
the S-shaped compensation capacitor will be changed, and the horizontal width will be also changed. The
vertical parabola waveform is generated inside IC601, and then mixed with the DC level for horizontal
width control. After that, the mixed parabola waveform will be output from 64 pin of IC601, and added to
IC5C0. This parabola output will be used for compensation of pin-cushion distortion, barrel distortion,
trapezoidal distortion, and upper/lower distortion.
1.2.4 Vertical deflection circuit
1.2.4.1 Sawtooth waveform generation, vertical size/position control, and linearity control circuit
If the vertical synchronization signal is input to 42 pin of IC601, the bipolar sawtooth waveform having the
same frequency as the input will be output from pins 1 and 11 of IC601. IC601 receives compensation
data from the MPU (IC102) to compensate the vertical size, vertical position, vertical raster position,
vertical linearity, and vertical linearity balance, and then outputs the compensated sawtooth waveforms
from pins 1 and 11. Pin 2 outputs the voltage to show the vertical deflection intermediate point.
The OP amplifier at the next stage outputs a signal to show the difference of the bipolar sawtooth
waveform. For this output, the RC low pass filter is adopted to eliminate the digital gradation of the output
waveform. In addition, pins 62 and 63 of IC601 will be turned ON during retracing operation in order to
prevent deterioration of the linearity and dispersion of scanning lines. Moreover, Q603 and Q604 are
switched depending on the vertical frequency in order to improve the linearity.
IC601
R652
VSAW-P
11
R658
R648+R649
IC603
R650 2 R645+R646
1 5 7
VSAW-N 1 3 6
R642
R647
R651 IC603
C628
IMID 2
Q604 SW-VLIN1
R637
63
Q603 SW-VLIN2
62
Fig. 2 Vertical sawtooth waveform output circuit
1.2.4.2 Vertical output amplification circuit
A current proportional to the waveform of the voltage input to IC401 will flow to the vertical deflection coil
(V-DY). R410 reads out the voltage waveform of the vertical deflection current, and then feeds back it to
IC401.
R419+R409
IMID R411 IC451 V-DY
5
- 2
4 +
V SAW Input R405 R410
Pump Up
R406+R418
1 6 3 7
VFLY
C404
-15.0V
D401
+15.0V
Fig. 3 Vertical output amplifier circuit
1.2.5 High voltage block
The high voltage block applies PWM control system that controls ON/OFF time of the high voltage
generation FET.
IC701 is the control IC that executes PWM control. The pulse voltage generated at Q701 is boosted at
T701 (FBT) to generate 27kV. To keep the high voltage stably, the feedback voltage from pin 10 of T701
is adopted, the control voltage from pin 56 of microcomputer IC102 is returned to pin 5 of IC701 and the
pulse wise of PWM output is controlled. PWM synchronizes with the horizontal frequency. Trigger pulse
for synchronizing is output from the divided collector pulse of the horizontal deflection output TR Q550,
and is input to pin 8 of IC701.
For adjustment of high voltage value, the voltage of pin 56 of IC102 is adjusted with the adjustment item
HV-ADJ-CAUTION on the OSM menu.
1.2.6 DBF (Dynamic Beam Focus) circuit
The horizontal/vertical DBF voltage is respectively generated and amplified, then synthesized at T7A1.
As for the horizontal DBF voltage waveform, the parabola waveform voltage (approx. 0.5Vp-p) is output
with IC601, and amplified about 10 times with OP-AMP IC6A2. After that, it is amplified to 50-60Vp-p
with Q7B5 (the amplification factor is about 10 times), then it is amplified about 10 times with T7A1.
On the other hand, as for the vertical DBF voltage waveform, the parabola waveform voltage (approx.
1.0Vp-p) is output from IC601. It is amplified about 40 times at Q7A1, and the vertical parabola wave is
superposed to the horizontal parabola wave on the secondary side of T7A1, then consequently
synthesized. The collector pulse voltage of the high voltage output TR (Q701) rectified at D7A1 and
C7A1 is used for the power source of Q7A1. The synthesized DBF waveform is input to pin 12 of T701.
1.3 Video block
1.3.1 Video signal amplifier circuit
D-SUB SEL
2
CN216 MPU 13 40 IC 601
IC102
B 13 IC 215
1 2 44 43 35 10
G
2 4
16 17 13 14
R G G
3 6 29 8 IC 210 5
SDA SCL CLP-IN Retrace
BLK in 27 R 9 MAIN 3 R
B
31 6 Amp
D-SUB 25 B 11 1 B
CN215 28
G 1
IC 211
Pre - Amp B OSD
1 B 10 R 11 17
IC212
25 3 G OSD
9 19 OSD
G 12 DAC DAC DAC DAC
2 S/G SEL R-Bias B-Bias G-Bias R OSD
10 18
23
18 19 20 21 15 8
R 14 16 11
3
OSD BLK
IC 216
DET
Analog-sw
BIAS circuit
Fig. 4 Video signal amplifier circuit
1.3.1.1 Video clamp
The clamp signal (positive polarity, 3.3 Vo-p) output from pin 35 of the MPU (IC102) is input to pin 13 of
IC211. The clamp signal is normally set to the back of the video signal (clamp position of OSM menu:
BACK). To correspond to the Sync on Green signal, the clamp signal can be set to the front of the video
signal (clamp position of OSM menu: FRONT). If the signal is a separate signal, changing the clamp
position of the OSM menu to FRONT or BACK will not change anything.
1.3.1.2 Video blanking
The horizontal/vertical retrace line (blanking) signal (positive polarity, 3.3 Vo-p) output from pin 40 of IC601
is input to pin 13 of IC215. IC215 reverses the polarity and amplifies the waveform (positive polarity,
3.3Vo-p -> negative polarity, 5.0Vo-p), and then reverses the polarity again (negative polarity, 5.0Vo-p ->
positive polarity, 5.0Vo-p) to output the blanking signal. This blanking signal is input to pin 14 of IC211 to
perform blanking operation during horizontal/vertical retracing operation.
To perform image blanking at switching the signal mode or at turning ON or OFF the power, the contrast
and the brightness will be set to MINIMUM.
1.3.1.3 Video mixing/amplifying
IC211 mixes the video signal with the OSM signal (G, R, and B signals of pins 9, 10, and 11) and with the
video blanking signal described in Sec. 1.3.1.2. I2C bus (pins 16 and 17 of SCL and SDA) fixes the black
level of the mixed video signal to 1.8V, and amplifies the mixed video signal (0.7Vp-p -> approx. 2.6Vp-p).
After that, the B, R, and G signals are output from pins 25, 27, and 29, respectively. The video signal
output from IC211 is input to IC210, where the signal is amplified (approx. 2.6Vp-p -> approx. 36Vp-p),
and the black level is fixed to 67V. After that, the B, R, and G signals are respectively output from pins 1, 3,
and 5.
1.3.1.4 Control of contrast and white balance
The MPU (IC102) sends the 8-bit contrast/white balance control data to IC211 with I2C bus (SCL, SDA
line). The contrast data simultaneously control 3 channels to simultaneously control the gains of the R, G,
and B, and the white balance data respectively controls the gains of the R, G, and B.
1.3.2 Cut-off control circuit
G G
29 8 5 GK
IC211 B IC210 B
25 11 1 BK
Pre-Amp MAIN-Amp CRT
R R
27 9 3 RK
19 21 20
215V LINE
B.BIAS
R250G R250B R250R
R251G
R251R
R251B
12V LINE
D250G D250B D250R
G.BIAS
D264
Q251G D251G D251B D251R
C250G
R252G
R261
R253G
Q251B
R.BIAS
C250B
R252B
R253B
Q251R
Q250G
R260
C250R
R252R
R253R
Q250B
Q250R
R255R
R255G
R256G
R254G
R256R
R254R
R255B
R256B
R254B
IC213
1 3 55 IC102
BRIGHT MPU
2
Fig. 5 Cut-off control circuit
The cut-off control circuit consists of Q250R, Q250G, Q250B, Q251R, Q251G, and Q251B, and
simultaneously adjusts 3 colors (brightness), or individually adjusts 3 colors (biases of R, G, and B). The
microcomputer controls both types of adjustment.
1.3.2.1 Control of brightness
To simultaneously adjust 3 colors (brightness), the DAC voltage (0 to 5V, variable) line of microcomputer
pin 55 is connected to the emitters of Q250R, Q250G, and Q250B via IC213. This connection enables
simultaneous control of three TR collector currents and adjustment of the brightness.
1.3.2.2 Control of BIAS
To individually adjust 3 colors (biases of R, G, and B), the DAC output (1.5 to 5.5V, variable) lines (pins 19,
20, and 21 of IC211) are respectively connected to the emitters of Q250R, Q250G, and Q250B via I2C
bus of the microcomputer. This connection enables respective control of three TR collector currents and
adjustment of biases of the R, G, and B.
1.3.3 OSM (On Screen Manager)
IC212 is the OSM (On-Screen Manager), and displays the screens for screen adjustment, etc. The data to
be displayed on the OSM screens is sent to the MPU (IC102) via I2C bus.
1.3.4 2 Input change circuit
The analog switch IC216 carries out the signal selection at the time of SIGNAL-A and B simultaneous
input. The signal selection is carried out by the SELECT signal of pin 3 of microcomputer IC102. By the
SELECT signal of pin 3, the input signal of SIGNAL-A is selected when pin 13 (SELECT SW) of the
analog switch IC206 is HIGH, and SIGNAL-B is selected when pin 13 (SELECT SW) of the analog switch
IC206 is LOW.
1.3.5 Sync on Green circuit
The Sync on Green signal input needs to make an image signal and a composite sync signal separate.
The separation method of the image signal and the composite sync signal is as follows. If a
microcomputer IC102 detects a Sync on Green signal, pin 18 S/G-SEL signals of IC211 will be set to
HIGH (5V), a transistor Q280 turns off, and the Sync on Green signal is output from pin 23 of IC216. The
Sync on Green signal output from pin 23 is input to pin 22 of IC216, it is divided to the image signal and
the composite sync signal at the inside of IC216, and only composite sync signal is output from pin 21.
1.3.6 Asset circuit
If the monitor power is turned OFF, 5V power will be supplied to pin 14 of EEPROM (IC217) from the PC
via pin 9 of CN216, and the data stored in the EEPROM (IC217) can be read out from I2C bus.
1.3.7 AUTO-SIZE function
The AUTO-SIZE function detects the phase data of RGB OR signal (output to pin 11 of OSM (IC212) from
pin 15 of AMP (IC211) from H-OSM and V-S signals input to pins 5 and 16 of IC212 in order to
automatically adjust the screen to the optimum width and position.
Using the OSM, select AUTO SIZE ADJUST, and then press (+) button to perform automatic size
adjustment.
1.3.8 SB MODE (Super Bright Mode) function
1.3.8.1 Adjustment item/operating function in selecting SB Mode
SUPER BRIGHT MODE OFF (in factory adjustment state)
SUPER BRIGHT MODE-1 ON (PICTURE)
SUPER BRIGHT MODE-2 ON (MOVIE)
User adjustment items related to luminance/color coordination
Color
Adjustment of Adjustment of Color mode Individual GAIN
temperature
brightness contrast selection adjustment
selection
SUPER BRIGHT MODE
Adjustable (*1) Adjustable (*1) Selectable Selectable (*2) Adjustable (*4)
OFF
SUPER BRIGHT MODE-1
Adjustable (*1) Adjustable (*1) Not-selectable Selectable (*2) Not-adjustable
ON
SUPER BRIGHT MODE-2
Adjustable (*1) Adjustable (*1) Not-selectable Selectable (*2) Not-adjustable
ON
(*1): Brightness and contrast are common among three display mode.
(*2): For color temperature, the adjustment value is memorized in every display mode.
(*4): See (*4) mentioned in item 1.3.8.3.
Back raster luminance GAIN UP compensation Sharpness
SUPER BRIGHT MODE
Normal Normal --- ---
OFF
SUPER BRIGHT MODE-1
Normal UP Presence ---
ON
SUPER BRIGHT MODE-2
UP UP Presence Presence
ON
1.3.8.2 Circuit (cathode) operation in selecting SB Mode [Window pattern]
SUPER BRIGHT MODE SUPER BRIGHT MODE-1 SUPER BRIGHT MODE-2
ccordance
Same amplitude
Amplitude: Approx. 36V
Amplitude: Approx. 44V
Amplitude: Approx. 44V
GND
1.3.8.3 SB Mode setting data and control method
(OSM FACT3) Data name Data (hex)
Setting of back raster SBBR1 0 BRT UP value in SUPER BRIGHT MODE-1 ON "0"=No UP
luminance SBBR2 32 BRT UP value in SUPER BRIGHT MODE-2 ON
Amplified value in SUPER BRIGHT MODE-1 ON
SBCN1 3C
(see the following formula)
Setting of GAIN UP
Amplified value in SUPER BRIGHT MODE-2 ON
SBCN2 3C
(see the following formula)
GAIN UP formula = GAIN adjustment value (hex)(*3) x {1+ (Data (hex) of SBCN1 or SBCN2)/FF (hex) }
(*3): GAIN adjustment value is the following data (in OSM FACT3).
9300K R-GN1 G-GN1 B-GN1
6500K R-GN2 G-GN2 B-GN2
5000K R-GN3 G-GN3 B-GN3
(*4): When the SUPER BRIGHT MODE-1 or MODE-2 is ON, the GAIN cannot be adjusted as shown in the
table in Sec. 1.3.6.1 "Adjustment item/operating function in selecting SB Mode". However, when the
SUPER BRIGHT MODE is OFF, the MAX GAIN value calculated with the following formula will be written in
the following EEP address so that the GAIN value cannot be increased above that of the SUPER BRIGHT
MODE-1 and MODE-2 ON status.
MAX GAIN = Maximum value (hex) for R/G/B GAIN adjustment (*5) x {1 + (SBCN1 or SBCN2 data
(hex))/FF (hex)}
(*5): R/G/B GAIN MAX value is the maximum one among GAIN adjustment value mentioned (*3) above.
EEP address (hex)
R G B
MAX GAIN 89 8a 8b
* Every R/G/B MAX GAIN data applied to the address listed above table are totally same.
In case of repair, after CRT, Pre-AMP (IC211), MAIN-AMP (IC210), etc. are replaced and the
luminance/color coordination is adjusted, the MAX GAIN value mentioned above should be rewritten.
1.3.9 CONSTANT BRIGHTNESS function
The brightness and color coordination of the screen will be deteriorated due to secular deterioration of the
CRT. The CONSTANT BRIGHTNESS function, however, will recover the deteriorated brightness close to
the initial level (level ensured at outgoing the factory).
If the CONSTANT BRIGHTNESS function is activated, operation will be performed at 106kHz horizontally
and at 85Hz vertically while ignoring the input signal, and the OSM-IC (IC212) will output the reference
image signal. In this condition, R744 detects the beam current flowing to pin 9 of the flyback transformer
T701. This beam current is inverted and amplified by IC703, and then converted into a voltage value by
the current/voltage conversion circuit. After that, the converted voltage value will be input to the A/D
converter (pin 27 of IC102 (microcomputer)). To individually detect the beam current values of 3 colors (R,
G, and B), the desired color only will be brightened by increasing the cut-off voltages of the other 2 colors.
After obtaining the beam current values of 3 colors in this way, the obtained beam current values will be
compared with the beam current values used for factory adjustment (beam current values stored in the
EEPROM). After that, the cut-off voltage values of 3 colors (R, G, and B) will be adjusted so that the beam
current values close to the factory adjustment values can be obtained. In this way, the cut-off conditions of
the CRT will be recovered close to the factory adjustment level.
In addition, if the CONSTANT BRIGHTNESS function is activated, the C_TIME_SEL signal input to the
base of Q704 will be set to the low level, Q704 is turned OFF, and the bias voltage will be applied to pin 5
of IC703. As a result, voltage proportional to the beam current value will be output from pin 7 of IC703. By
the way, difference in the flyback transformer or the CRT may cause difference in the beam current. To
eliminate such difference in the beam current, the DAC voltage (commonly used for the 6H-DC signal) can
adjust the bias voltage input to pin 5 of IC703 described above. During normal operation, the
C_TIME_SEL signal is set to the high level, Q704 is turned ON, and pin 5 of IC703 is grounded via the
GND line so that the output of IC703 pin 7 can be kept at the low level. The signal output from pin 7 of
IC703 is added to ABL signal with MD717 (Diode). When the CONSTANT BRIGHTNESS function is
activated, the ABL signal is input to pin 27 of IC102 as the beam current signal.
1.4 CRT compensation block
1.4.1 Earth magnetism cancel circuit
This model carries IC2S0 (geomagnetism sensor unit) that carries out the voltage conversion of the
magnetic field intensity of a north-south magnetic field and an east-west magnetic field. IC2S0 detects
the detected voltage and controls the various canceling functions described below automatically.
·South-north horizontal magnetic field rotation canceling function
·East-west horizontal magnetic field raster vertical position canceling function
·South-north horizontal magnetic field landing canceling function
·East-west horizontal magnetic field landing canceling function
·South-north horizontal magnetic field convergence canceling function
·East-west horizontal magnetic field convergence canceling function
Here, the output voltage of IC2S0 (earth magnetism sensor unit) operates as follows.
·South-north horizontal magnetic field (IC2S0 pin 5): 1.0V (-0.04mT) to 2.5V (+/-0.00mT) to
4.0V(+0.04mT).
·Vertical magnetic field (IC2S0 pin 4): 4.0V (-0.04mT) to 2.5V (+/-0.00mT) to 1.0V (+0.04mT).
(a) Landing compensation
V-6H (Schematic Diagram) and PWB-V-6H (PWB) are added so that the CRT specified for Northern
Hemisphere ITC can be adjusted to the spec for Southern Hemisphere ITC.
Some circuits are also added to DEFL-SUB (Schematic Diagram) and PWB-DEFLSUB (PWB).
In PWB-V-6H a vertical sync. parabola waveform output from pin 59 of IC601 (1 bit DAC) is supplied
from pin 1 of CN804 and 300mAp-p parabola waveform (vertical sync.) current flows to the speed
modulating coil from pin 1 of CN8P2 via Q8P0 and Q8P1.
In PWB-DEFLSUB a vertical sync. parabola waveform output from pin 59 of IC601 (1 bit DAC) is
reversed and amplified via Q600 and it is associated to the horizontal phase deflection compensation
waveform output from pin 57 of IC601 to compensate side pin balance.
(b) Vertical magnetic filed landing cancel
The vertical magnetic field landing cancel circuit is the one to compensate the color shade and
deviation that reaches its maximum at the center in the horizontal axis direction and its minimum at
the upper and lower ends on the monitor surface.
The automatic adjustment is done by controlling DC level of the above 300mAp-p parabola waveform
flowing to the speed modulating coil installed in the neck part of CRT.
It is controlled by pin 46 of IC 102 (DAC "V CANCEL"), and controls the speed modulating coil with
DC level of +/-50mA by Q8P0 and Q8P1.
(c) Vertical magnetic field convergence cancel
The vertical magnetic field convergence cancel circuit is the circuit to compensate for the
misconvergence that results after the vertical convergence of RED and BLUE reversed at the upper
and lower ends on the whole display area of the monitor deteriorates, and it is automatically adjusted
by the saw-toothed waveform (vertical-frequency) current flowing to the 4V convergence
compensation coil mounted on DY. It is controlled with the AC component (YVJT & YVJB, vertical
frequency saw-toothed waveform) by pin 60 of IC601 (4V_SC), and saw-toothed waveform (vertical
frequency) current of +/-45mA (peak) is made to flow to the 4V convergence compensation coil by pin
6 of IC8A1 (PowerOpamp).
1.4.2 Rotation circuit
The rotation circuit is a circuit to compensate the picture inclination caused by the earth magnetism by
letting DC current flow to the rotation coil wound on the front side of DY for adjustment. It is controlled to
0 to 5V with the reference of 2.5V by IC102 pin 45 (PWM_DAC), and DC current of +/-100mA (max) is
made to flow to the rotation coil by IC804 pin 2.
This compensation circuit has two functions; (1) User adjustment (OSM display) and (2)
Southern/Northern horizontal magnetic field rotation cancellation.
1.4.3 East-west horizontal magnetic field vertical position canceling function
It is the function that detects the detection voltage change from IC2S0 (geomagnetism sensor unit) by
east-west horizontal magnetic field change, and cancels a changed part of a raster vertical position
automatically.
1.4.4 Corner purity circuit
The corner purity circuit is a circuit to compensate for the color shade and color deviation of the picture
corner. On the rear side of CRT, it is adjusted by DC current flowing to the corner purity coils installed in
the four corners on the display surface.
The compensation circuit is composed of the following five functions of (1) User adjustment (OSM display),
(2) Aging variation compensation, (3) High/low temperature drift compensation, (4) South-north horizontal
magnetic field landing cancel and (5) East-west horizontal magnetic field landing cancel.
(1) User adjustment (OSM display)
The user causes DC current of +/-60mA (max) to flow to the purity coil of each corner according to the
value displayed on OSM.
(2) Aging variation compensation
As the electronic beam collides with the aperture grille, it is thermally expanded and contracted. The
thermal expansion/contraction is varied according to the elapse of the power ON/OFF time of the
monitor. The color shade and deviation of the picture corner thus generated are automatically
adjusted.
The voltage of the beam current supply pin (T701 pin 9) is detected with R723/R724, and the voltage
that detects the time elapse of the power ON/OFF of the monitor is read from the CR charge
(integration) circuit composed of C723 and R738, and CR discharge (integration) circuit composed of
C723 and R737 through IC702 (buffer amplifier) by IC102 pin 26 (CPU_ADC), then, the DC current of
+/-19mA (max) flows to the purity coil on each corner according to the specified control program.
(3) High/low temperature drift compensation
The front panel (glass) is thermally expanded and contracted as the temperature varies in the
installation environments of the monitor. The color shade and deviation of the picture corner are
automatically adjusted. The voltage that detects the temperature va