Hitachi 15LD2200, Руководство по обслуживанию

Страница: 39 / 58

37
15” TFT TV Service Manual
No:
Name: Function:
Group:
Default:
170 LCD-CON-AV1S
Sub System 32
171 LCD-CON-AV2 AV CVBS contrast adjust.
Sub System 32
172 LCD-CON-AV2S S-Video input contrast adjust.
Sub System 32
173 RBL
Sub System 0
174 EGL
Sub System 0
175 LPG
Sub System 1
176 PGR UOC Red Contrast
Sub System 32
177 PGG-CVBS UOC Green Contrast for CVBS input
Sub System 32
178 PGG-RGB UOC Green Contrast for RGB input
Sub System 34
179 PGB UOC Blue Contrast
Sub System 32
4.1.2.
Tuner AGC Alignment
In this part, tuner AGC alignment procedure is described.
A TV pattern generator with RF output and volt-meter are needed for this alignment.
Test Set-up
“NICAM Stereo” and 60 dB PAL B/G RF signal from pattern generator will be applied.
Frequency must be set to 224.25 MHz.
• Turn on the TV and measure the AGC voltage from Tuner Pin1 without plugging in any
RF input (Around 4.12V).
• Apply “NICAM Stereo” and 60 dB(1 mV) PAL B/G RF signal to the tuner input.
• Enter UOC service menu (as described above), and go to “AGC
Take over”
setting by
pressing
“1” “1” “8”
.
• Measure AGC voltage from Tuner Pin1. By pressing /-; adjust AGC voltage so
that the measured value at this step should be 0,5V less than the value measured at first
step (Around 3.5V).
4.1.3.
DCXO Alignment
If this alignment has not properly been done, some front end RF problems can be observed such
as Nicam stereo / mono sound switching, low RF reception and color separation performance.
Test Set-up
This alignment will be performed just after Tuner AGC Alignment. Apply “NICAM Stereo” and 60
dB PAL B/G RF signal from pattern generator. Frequency must be set to 224.25 MHz.
• Turn on the TV.
• Enter UOC service menu (as described above), and go to “DCXO Auto” setting.
• Set “DCXO Auto” value to “1” by pressing “”.
• TV will automatically align the DCXO (Digital Controlled Xtal Oscillator) value.
• Then TV automatically re-sets “DCXO Auto” value to “0”. This indicates that DCXO
Alignment successfully completed.
4.2. PW1306 Service Menu
• In order to work with PW service menu:
• Press “Menu” (M) and “4” ”7” “2” “6” buttons of RC respectively.
• Make the desired settings.
• Press “Menu” (M) from RC to turn off the PW Service menu
• The menu has the following structure: