Hitachi CM721FET, Руководство по обслуживанию

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1. DISPLAY ALIGNMENT
A. Display Size
All preset mode listings in Table 1. shall be within the following limitations:
H. WIDTH: 350 ± 4 mm
V. HEIGHT : 260 ± 4 mm
B. Picture Position
All preset mode listings in Table 1 shall be within the following limitations:
H. PHASESCREEN : SCREEN CENTRE ± 4 mm
V. CENTERSCREEN : SCREEN CENTRE ± 3 mm
C. Linearity
The CONTRAST and BRIGHTNESS control shall be properly adjusted at 15 F-L with Full-intensity reverse
pattern, then change to crosshatch Pattern. The measured values of linearity should be less than 10% when
calculated using all latticrs and should be less than 6% when calculated using adjacent lattices.
The calculation formula was listed below:
H max - H min V max- V min
x100% or x100%
( H max + H min)/2 ( V max + V min)/2
D. Geometry Distortion (all preset modes)
The CONTRAST and BRIGHTNESS control shall be properly adjusted at 15 F-L with full-intensity reverse
pattern, then switch to cross hatch pattern and place unit facing east.
Pincushion should be less than 2.0mm
Barrel should be less than 2.0mm (top & bottom)/ 1.5 (left side & right side)
Trapezoid should be less than 3.5mm Parallelogram should be less than 3.5mmTilt should be less than 1/2 degree.
E. Alignment Procedure
E-1. Brightness Adjust:
1. Adjust the VR980 so that the +15VS rail is 14.9V
±
0.1V (The voltage of the C944) in TIMING 1.
2. Check the voltages below :.
C974 : 202
±
3V
C947 : 76
±
2V
C946 : 44
±
1.5V
C940 : 10.4
±
0.4V
C959 : 12
±
0.3V
3. Short-Circuit protection function check.
The power source is 230VAC input.
When C944 is shorted, all output voltage should be shut down and unlatch.
When normal condition is recovered, all output voltage should recover automatically.
E-2. Light output adjust
Select Timing 1, preset BRI. And CONT. to max. position.
Adjust G2 to get G2 = 550V
±
10V
Adjust VR803 to get light output = 0.3FL ~ 0.6FL
Select Timing 2, adjust VR405 to get pattern over scan. (H SIZE 100%)