7
The adjustment result should satisfy the scan linear geometric distortion and over scan (rate of
recurrence)
4.9 Adjustment of screen-grid Focus and VG2
4.9.1
Adjust FBT Focus pole potentiometer until picture is clear.
4.9.2
Enter factory menu Cathode current (G2) item, (AV should be kept empty then), push VOL+,
change to bright horizontal line and adjust the potentiometer of the line pack acceleration pole
in such a way that the bight horizontal line becomes slightly bright.
4.10 White Balance Adjustment
4.10.1
Enter “Cutoff ref” adjustment of factory menu. It’s enough only to fine adjust the dark
balance. Under 4.5 Niete, color temperature 8MPCD
(
X=0.270
,
Y=0.283
)
.
4.10.2
Enter Drive ref item adjustment of factory menu. The bright balance will be automatically
adjusted at a certain white coordinate place. Under 60 Niete, color temperature
2000K+8MPCD
(
X=0.270
,
Y=0.283
)
.
4.11 Inspection of the high voltage and filament voltage
4. 11. 1
Connect high voltmeter between the high voltage cap and the earth. Measure the filament
voltage with an actual value and effective voltage meter.
4.11.2
Receive D35 signal, set the picture mode at “dynamic”, and measure the high voltage and
filament voltage. The voltage for 29” “Yongxin” extra pure flat should be: high voltage- 29 kV
±
0.5 kV; 29
″
pure flat, high voltage- 30 kV
±
0.5 kV
,
filament voltage- 6.3
±
0.3 Vrms.
4.12 Inspection of X-ray protection
4.12.1
Receive normal picture.
4.12.2
Push switch S301. The line scan should stop vibrating and shut the set off.
4.12.3
Shut off the main power supply, re-power it on in 30 seconds. It should be back to normal.
4.13 Inspection of beam current
Receive D35 signal, set the picture mode at “dynamic”, and measure the two terminals of TP9,
TP10. For ultra pure flat it should be
≤
1.6 V, and for 29
″
pure flat,
≤
1.7 V.
4.14 Inspect ion of AV function
VIDEO IN: 1 Vp-p 75
Ω
, AUDIO IN: -8 dBm
±
3 dBm
>
47 k
Ω
.
As per instruction manual, connect audio and video equipment with AV terminal of the set to
be tested. The inter-connection should be made to meet the following requirements:
VIDEO IN: 1 Vp-p 75
Ω
, AUDIO I: -8 dBm
±
3 dBm
>
47 k
Ω
.