Hitachi CM621FET User manual

CAUTION:
Before servicing this chassis, it is important that the service technician read the “Safety
Precautions” and “Product Safety Notices” in this service manual.
ATTENTION:
Avant d’effectuer l’entretien du châassis, le technicien doit lire les «Précautions de sécurité»
et les «Notices de sécurité du produit» présentés dans le présent manuel.
VORSICHT:
Vor Öffnen des Gehäuses hat der Service-Ingenieur die „Sicherheitshinweise“ und „Hinweise
zur Produktsicherheit“ in diesem Wartungshandbuch zu lesen.
SERVICE MANUAL
MANUEL D'ENTRETIEN
WARTUNGSHANDBUCH
Data contained within this Service
manual is subject to alteration for
improvement.
Les données fournies dans le présent
manuel d’entretien peuvent faire l’objet
de modifications en vue de perfectionner
le produit.
Die in diesem Wartungshandbuch
enthaltenen Spezifikationen können sich
zwecks Verbesserungen ändern.
SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT
Colour Monitor
June 2001
No. 0419
CM621FET

1. DISPLAY ALIGNMENT...............................................................1
A. Times & Display Size................................................................................................... 1
B. Picture Position.............................................................................................................1
C. Linearity........................................................................................................................ 1
D. Alignment Procedure.................................................................................................... 2
E. Geometry Distortion ..................................................................................................... 2
F. Tilt................................................................................................................................. 2
G. White Balance Alignment ............................................................................................ 3
H. Preset Timing................................................................................................................4
2. CONTROL AND CONNECT LAYOUT ........................................5
A. Main PCB .....................................................................................................................5
B. Video PCB ....................................................................................................................6
C. Pin Assignment............................................................................................................. 7
3.INTRODUCTION..........................................................................8
A. Power Supply................................................................................................................ 8
B. Deflection ..................................................................................................................... 8
C. Video ............................................................................................................................ 8
D. Digital Controllor ......................................................................................................... 8
4. POWER SUPPLY .......................................................................11
A. Rectifier and Filter Circuit ........................................................................................... 11
B. Flyback and PWM Circuit............................................................................................ 11
C. Subber Circuit............................................................................................................... 11
D. Synchronized Circuit.................................................................................................... 11
E. Power Saving Circuit .................................................................................................... 11
F. Degauss Circuit ............................................................................................................. 12
G. Overload Protection Circuit ............................................................................ 12
5.DEFLECTION ..............................................................................13
A. Sync Processor.............................................................................................................. 13
B. Horizontal Processor..................................................................................................... 13
C. Vertical Output ............................................................................................................. 13
D. Dynamic Focus Section................................................................................................ 13
E. Horizontal Output Stage ............................................................................................... 13
F. Flyblack Transformer.................................................................................................... 13

6.VIDEO AMP. CIRCUIT.................................................................16
A. Video PRE. AMP. ........................................................................................................ 16
B. Video Amplifier............................................................................................................ 16
7. TROUBLESHOOTING ................................................................19
A. Power Supply Check .................................................................................................... 19
B. Monitor Check Flow Chart........................................................................................... 20
APPENDIX A: SCHEMATIC DIAGRAMS ......................................23
APPENDIX B: DISPLAY UNIT ASSEMBLY DIAGRAMS .............27
APPENDIX C: PART LISTS ..........................................................29

WARNING
1) This product contains components which are critical for X-radiation safety. Read the Service manual
carefully for proper replacement. Maximum 2nd anode voltage use high impedance meter, connect (-) to
chassis, use a high voltage lead from (+) to 2nd anode.
2) Critical Components are marked with the symbol of in the material list. For continued protection
against X-radiation, replace only with same type and rating components.
3) Critical Components are marked with the symbol of # in the material list. For continued protection
against Low Radiation, replace only with same part number.
4) This symbol warns the personnel that un-insulated voltage within the unit may have sufficient
magnitude to cause electric shock.
Therefore, it should be read carefully in order to avoid any problems.

1
1. DISPLAY ALIGNMENT
A. TIMING & DISPLAY SIZE
For all presetting mode shall be within the limitation:
H. WIDTH 300 ± 5mm
V. HEIGHT 225 ± 3 mm
The external control range of the data area, shall be as follows;
Max. horizontal size : overscan the screen
Min. horizontal size : ≤285mm
Max. vertical size : over the screen
Min. vertical size : ≤202 mm
B. PICTURE POSITION
For all presetting mode shall be within the limitation:
H.PHASE SCREEN CENTER ± 3 mm
V.CENTER SCREEN CENTER ± 2 mm
The external control ranges of display for all modes listed in section 2.4
H.POSITION ≥50 mm
V. C E N T E R ≥25 mm
C. LINEARITY
The CONTRAST and BRIGHTNESS control shall be properly adjusted at 20 F-L with Full-intensity reverse
pattern, then change to crosshatch Pattern 12x10 (H x V), the size of grid of crosshatch pattern in every display
mode shall not vary than 5%(P) or 6%(S).If two line is next to each other, 6%(P) or 7%(S) if they are not next to
each other. The calculation formula was listed below:
Hmax - Hmin Vmax - Vmin
x100% or x100%
Hmax + Hmin Vmax + Vmin

2
D. ALIGNMENT PROCEDURE
• Warm up the monitor for at least 30 minutes before adjustment.
• Set the front of CRT to the east.
• Turn all VR set to center position.
D-1. H.V
1. Use frontcontrol keyadjust the displaysize about300mm,adjustVR801 Letthe High voltageof Circuit
is26KV inTiming68K mode CROSSPATTERN.
E. GEOMETRY DISTORTION
1. Pincushion
Pincushion(top) d1<=2.0mm(p) or 2.5mm(s)
Pincushion(bottom) d2<=2.0mm(p) or 2.5mm(s)
Pincushion(leftside) a1<=1.5mm
Pincushion(rightside) a2<=1.5mm
”S”distortion <=0.5mm(p) or <1mm(s)
2. Barrel
Barrel(top) c1<=2.0mm
barrel(bottom) c2<=2.0mm
barrel(leftside) b1<=1.0mm
barrel(rightside) b2<=2.0mm
3. Trapezoid & Parallelogram distortion
a<=2.5mm (p) or 3.0mm (s)
b<=2.5mm (p) or 3.0mm (s)
F. TILT
The maximum variation of the display rotation (tilt) shall be such that the following relationship shall be
met:
<=0.5 DEGREE FACE EAST

3
G. WHITE BALANCE ALIGNMENT
G.1.1 Select timing #6 (VESA 68K 1024X768) with crosshatch pattern, adjust both horizontal and
vertical OSD’s size control to get display size within 300x225p±2mm.
G.1.2 Disconnect RGB signal inputs,adjust OSD’s brightnessand G1 control to it’s maximum
position.
G.1.3 Auto alignment (P103 mustbe short)
Use automatic alignment equipment and program to get color temperature within specified
coordinates.
G.1.4 Manual alignment
P103 must be short in order to into factory mode. Select OSD function to color temperature
adjustment.
G.1.5 For 9300 colourcoordinate(note: the minimum value of RGB bias is 50) adjust bias Gto get
Y=311, then adjust bias R to get X=281. Reduce G1 to Y=0.8FL, fine tune bias G to get Y=311,
and let raster color coordinate is X=281
± 3, Y=311 ± 3, Y=0.8 ± 0.1FL.
G.1.6 Adjust brightness control to get raster is 0.06FL. reconnect R.G.B. input signal and change
pattern to 2 inch square, adjust gain B to get Y=311, gain R to get X=281.]
G.1.7 Check Y=51
± 1FL, if not adjust G to get Y=51FL, then repeat item 2.5.6
G.1.8 Change pattern to fall white, adjust SB to get Y=32
± 1FL.
G.1.9 Select6500 and 5000 colourcoordinate separately. Repeat item 2.5.5 ~ 2.5.8 to meet specificity.
6500 X=313 Y=329
5000 X=332 Y=349

4
H. PRESET TIMING:
PRESET MODE TIMING
MODE H Pixes
V Lines
Fd(MHz)
Polar(H/V)
Fh(KHz)
Fv(Hz)
Th(us)
Tv(ms)
Td(us)
Td(ms)
Tb(us)
Tb(ms)
Tp(us)
Tp(ms)
Tf(us)
Tf(ms)
d:dot B.G:
d:display
A.F:
backporch
D.I:
Pulse
C.H:
front
1 IBM
VGA
640
480
25.175
N/N
31.47
59.94
31.778
16.683
25.422
15.253
1.907
1.048
3.813
0.064
0.636
0.318
2 VESA 800
600
49.5
P/P
46.874
75
21.333
13.333
16.162
12.8
3.232
0.448
1.616
0.064
0.323
0.021
3 VESA 800
600
56.25
P/P
53.674
85.061
18.631
11.756
14.222
11.179
2.702
0.503
1.138
0.056
0.569
0.018
4 VESA
(Primary)
1024
768
78.75
P/P
60.023
75.029
16.66
13.328
13.003
12.795
2.235
0.466
1.219
0.05
0.203
0.017
5 VESA 1280
1024
108
P/P
63.981
60.02
15.63
16.661
11.852
16.005
2.296
0.594
1.037
0.047
0.444
0.016
6 VESA 1024
768
94.5
P/P
68.677
84.997
14.561
11.765
10.836
11.183
2.201
0.524
1.016
0.044
0.508
0.015
Remark:
(1). Primary preset: This is primary timing,match the marked (p) item in engineering
specification.
(2). Secondary preset: The other preset timing shall match the marked (s) item in
engineering specification.

5
2. CONTROL AND CONNECT LAYOUT
A. Main PCB

6
B. Video PCB