VRX775VD
VRX776VD
- 5 -
ADJUSTMENT
* The NTSC (K-A:PAL)composite output signal of the
signal generators of adjustment is performed with the
following output.Video input of visual mode.
A image signal: 714mV
A synchronized signal: 286mV
Sub PWB section
* Refer to the printed circut board(36 page)for an adjust-
ment point and VR.
1. Confirm the power supply voltage
Input signal: 10-steps wave
Measurement is performed by composite screen
display.It measures by digitalbolt meter and DIMMER is
100%.
1-1.Adjust VR551 so that voltage of TP593 is 5.30 +0.02/-
0.02V.
Caution: A LCD controller will be damaged if the voltage
beyond 5.45V is added.
1-2.Confirm that TP556 is 3.3 +0.2/-0.2V
1-3.Confirm that TP558 is 7.5 +0.2/-0.2V
1-4.Confirm that TP559 is 18.5 +0.8/-0.8V
1-5.Confirm that TP555 is -12.0 +0.5/-0.5V
LCD PWB section
* Refer to the printed circut board(39,40 pages)for an
adjustment point and VR.
2. Confirm the PLL lock
Input signal: 10-steps wave
2-1.It checks that see a screen and 10 gradation display do
not have a synchronous flow.
After checking and uniting the freerun frequency of item
9.when the synchronoization cannot be taken.
3. BRIGHT voltage adjustment
Input signal: 10-steps wave
Mesurement is performed by composite screen display.
It measures by digital bolt meter.
3-1.Adjust VR804(BRIGHT) so that the voltage of
TP805(BRIGHT) will become 2.00 +0.02/-0.02V.
4. RGB-AMP adjustment (black-black)
Input signal: 10-steps wave
Measurement is performed by composite screen display.
It measures with an oscilloscope.
4-1.Adjusts VR805 so that the black-black level (V B-B) of
the waveform of TP861 (G) will become 4.0 +0.1/-0.1V.
(Refer to Fig. 1)
5. Contrast adjustment (black-white)
Input signa: 10-steps wave
Measurement is performed by composite screen display.
It measures with an oscilloscope.
5-1.Adjusts VR801 so that the black-black level (V B-w) of
the waveform of TP861 (G) will become 3.8 +0.1/-0.1V.
(Refer to Fig. 1)
6. Gamma voltage check
Input signal: 10-steps wave
Measurement is performed by composite screen display.
It measures with an oscilloscope.
6-1.Confirm the waveform of TP861(LCD G) that ten grada-
tion has come out.
6-2.It checks that it is the 3rd gradation is 2.3+0.2/-0.2V.
6-3.Confirm that TP806(Gamma 0) is 2.30 +0.20/-0.20V
6-4.Confirm that TP807(Gamma 2) is 2.13 +0.20/-0.20V
7. White balance adjustment
Input signal: 10-steps wave
Measurement is performed by composite screen display.
It measures DC range of an oscilloscope.
* Are careful in order to perform correctly white balance
adjustment.
* The range of CH1,CH2 of an oscilloscope is used as
1V range.
* CH1,CH2 are indicated by GND and GND is united.
(Refer to Fig. 2)
7-1.White balance red adjustment
7-1-1.The waveform of TP861 is displayed on CH1 of an
oscilloscope, and the waveform of TP862(LCD-R) is dis-
played on CH2.
7-1-2.Adjust VR802(BRT-R) so that the waveform of
TP862(LCD-R) will become the same as the waveform
of TP861.
7-2.White balance blue adjustment
7-2-1.The waveform of TP861 is displayed on CH1 of an
oscilloscope, and the waveform of TP860(LCD-B) is dis-
played on CH2.
7-2-2.Adjust VR803(BRT-B) so that the waveform of
TP860(LCD-B) will become the same as the waveform
of TP861.
8. VCOM AC adjustment
Input signal: 10-steps wave
Measurement is performed by composite screen display.
It measures with an oscilloscope.
8-1.Adjust the VR806(VCOM AC) so that amplitude of a
waveform of TP852(VCOM AC) is 7.0+0.1/-0.1V.
There are no abnormalities, such as distortion, in a wave-
form.
CH1
CH2
(KI
2
(KI
1
