Sony GDM-F520 (serv.man3) Service Manual ▷ View online
GDM-F520(E)
2-1
SECTION 2
SAFETY RELATED ADJUSTMENT
HV Regulator
Circuit Check
HV Protector
Circuit Check
Beam Current
Protector Circuit
Check
When replacing or repairing the shown below table, the following
operational checks must be performed as a safety precaution against X-rays
emissions from the unit.
Part Replaced (
[)
RV901
HV ADJ
* Confirm one minute after turning on the power.
Part Replaced (
])
D Board
C925, IC901, R901, R902, R905,
R924, R925, R926, RV901, T901
(FBT)
• Mounted D Board
D Board
C920, C923, D911, D912, R903, R917,
R918, R919, R920, R923, T901 (FBT)
• Mounted D Board
N Board
IC1001, RB1001
• Mounted N Board
D Board
C930, D917, R921, R932, R933, R935,
T901 (FBT)
• Mounted D Board
N Board
IC1001, RB1001
• Mounted N Board
a) HV Regulator Circuit Check
1) Turn the RV901 slowly, and adjustment so that high voltage is in the
specified range.
[Specification]: 27.00 ± 0.05 kV
2) Check that the voltage of D912 cathode on the D board is 17.0 V or
more.
b) HV Protector Circuit Check
1) Using external DC Power Supply, apply the voltage shown below
between cathode of D912 and GND, and check that the RASTER
disappers.
[Specification]: 19.95 + 0.00/– 0.05 V
c) Beam Current Protector Circuit Check
1) Connect constant current source to a section between T901 (FBT) qa
pin and GND, and check that the RASTER disappers when the
specified current flows to the qa pin.
[Specification]: 2.12 + 0.00/– 0.01 mA
GDM-F520(E)
3-1
SECTION 3
ADJUSTMENTS
Note: Hand degauss must be used on stand-by or power-off condition.
This model has an automatic earth magnetism correction function by using an earth magnetism sensor and a LCC coil.
When using a hand degauss while monitor (LCC coil) is being operated, it sometimes gets magnetized, and the system may
not work properly as a result.
When using a hand degauss while monitor (LCC coil) is being operated, it sometimes gets magnetized, and the system may
not work properly as a result.
•
Landing Rough Adjustment
1. Display all white pattern (or black dot pattern).
2. Set contrast to 255.
3. Display green plain pattern.
4. Side back DY and roughly adjust green plain pattern to be centered on
the useful screen with Purity Magnet.
5. Adjust DY tilt.
Note: Set ROTATION to 128 and LCC_NS to 128 when adjusting DY tilt.
6. LIghtly tighten the DY screw.
•
Landing Fine Adjustment
Note: (1) After adjust W/B (9300k), measure the average of IK with all
white video input, while CONTRAST is maximum and
BRIGHTNESS is center. And adjustment shall be made so that
the miss-landing become least after aging 2H with the IK 30% of
measured value shown above.
(2) The magnetic field shall be BH = 0.
(3) When adjusting at other than BH = 0, calculate the shifted value
from BH = 0.
1. Put the monitor in helmholz coil.
2. Set as follows;
LCC_SW = 0
(LCC Correction Current = 0)
FUNCTION_SW bit1 = (Auto Degauss = On)
CONTRAST = 255
3. Display green plain pattern.
4. Degauss the iron part of chassis with a hand degausser and degauss coil.
5. Degauss CRT face with a hand degausser again.
6. Input AC 230V to AC IN and turn the monitor off and on. Then auto-
degauss works.
7.
Reset FUNCTION_SW bit1 to 0 (auto-degauss = off)
8.
Degauss CRT face with a hand degausser again.
9.
Attach wobbling coil to the specified place on CRT neck.
10. Put on landing sensor to CRT face.
11. Set LCC_SW to 12.
12. With landing checker, adjust DY position, purity, DY center and
landing of the 4 corners.
13. Read VX and VY value which are the read out of magnetic sensor, and
write to "LCC_VX_REF" and "LCC_VY_REF".
GDM-F520(E)
3-2
± 6
± 6
± 6
± 6
± 6
± 6
± 6
± 6
± 6
(µm)
10
10
10
10
7
10
10
10
10
(µm)
The red and blue must be within the
specification given right with re-
spect to the green.
specification given right with re-
spect to the green.
A difference between red and blue
must be within the specification
given right.
must be within the specification
given right.
<Specifications>
Adjust so that the green is within
the specification given right.
4 corner adjust target : within ± 1
Adjust so that the green is within
the specification given right.
4 corner adjust target : within ± 1
0 ± 3 0 ± 7.5 0 ± 3
0 ± 3 0 ± 7.5 0 ± 3
0 ± 3 0 ± 7.5 0 ± 3
(µm)
14. Adjust landing by LCC_NS, LCC_LT, LCC_LB, LCC_RT, and
LCC_RB. Adjustment of registers shall be limited within the following
range.
LCC_NS: 128 ± 15
LCC_LT, LCC_LB, LCC_RT, and LCC_RB: 128 ± 40
a
b
c
d
<How to place wedge>
Green plain crosshatch pattern
Green plain crosshatch pattern
a and b should be equal.
c and d should be equal.
c and d should be equal.
Plaster RTV to both sides for the upper wedge.
Make sure that they settle inside DY.
Plaster RTV to one side for other wedges.
Set LCC_SW to 13, and Perform Service Save.
15. Tighten DY screw within specified torque, and auto-degauss.
Note: Torque 22 ± 2 kgcm (2.2 ± 0.2Nm)
16. Adjust the vertical angle of DY to make top and bottom pins equal (a =
b). The horizontal angle shall not be changed (straight). Settle DY
upright without leaning, and insert wedges firmly so that DY shall not
move.
17. Adjust top and bottom pins correction VR.
18. Adjust the horizontal trapezoid distortion by DY horizontal trapezoid
correction VR.
GDM-F520(E)
3-3
19. Check landing at each corner and in case not in specification, adjust
landing of 4 corners with "LCC_NS", "LCC_LT", "LCC_LB",
"LCC_RT", and "LCC_RB". The limitations of registers are shown
below.
LCC_NS: 128 ± 15
LCC_LT, LCC_LB, LCC_RT, and LCC_RB: 128 ± 40
20. Remove the sensor and wobbling coil.
21. Switch signals to R, G, and B, and then check that the pure colors have
good color purity.
22. Fix purity magnets with white paint.
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