XOCECO M2019, Руководство по обслуживанию

Страница: 7 / 39

5
white balance basically normal.
4.2 Set the color to 0, contrast to 10, use oscilloscope to adjust CRT’s red gun’s waveform (see below figure),
adjust brightness to make the seventh step’s (the darkest) DC level be 180V, adjust accelerating electrode
to make the seventh step slightly light up (just can separate the seventh step and below dark field).
4.3 Fine adjust white balance (color temperature: 12000K
±
8MPCD X=0.270
±
0.008 Y=0.283
±
0.008 )
4.4 Set contrast,brightness,color all to 0, adjust BRTN to make A-7’s upper left 2 lattice slightly light up.
5. Horizontal, vertical scan center adjustment
NTSC(60Hz)H-center,V-center adjustment
Receive G23 signal, set user control to
“
DYNAMIC
”
state, adjust V-center V-position
，
H-PHASE to
make picture’s center be in accordance with screen’s center.
6. Vertical scan amplitude adjustment
NTSC(60 Hz)V-amplitude adjustment
Receive D35 signal, set user control to
“
DYNAMIC
”
state, adjust V-amplitude V-SIZE to make picture’s
upper and lower over scanning be screen size’s 8%.
Checking point
1. High voltage check
1.1 Connect high voltage meter to CRT’s second anode and GND.
1.2 Receive D-8 signal, set user control to
“ DYNAMIC ” state, the high voltage should be 29.0 kV ± 1 kV
(21” PF and 25”) or 25.0kV
±
1kV (14” PF) or 26.5kV
±
1kV (21”).
1.3 When brightness and contrast be set to minimum (zero beam current), the high voltage should not exceed
32 kV.
2. CRT filament voltage check
Receive D-8 signal, set picture control to
“
DYNAMIC
”
state, use effective value voltmeter to test CRT
filament voltage, the reading should be (6.3
±
0.3)Vrms.
3. X-ray protection check
3.1 Receive D-8 signal, set user control to “ DYNAMIC ” state.
3.2 Short R305(TP301,TP302),X-ray protection circuit should effect.
Fig 2: red gun waveform
180V
0V