Tatung VL5A9DA, Service Manual

Page: 17 / 89

17
PERIPHERAL PANEL BLOCK
Note: “Panel vdd “ and “backlight on-off ” can be direct control by :
GMZAN1 or MCU
Some panel can direct control by GMZAN1 ,if the relative timing between panel-vdd and backlight on-off
is short ( under 80 ms) , otherwise, will be control by MCU
If J211 be connected, that means Panel-VDD control was by GMZAN1 ,otherwise by MCU( JP212)
If J300 be connected, that means Backlight control was by GMZAN1 ,otherwise by MCU ( JP301)
BUT Hannstar panel & CPT panel still control by J211 & J300
FOR HANNSTAR-PANEL , there is the relative timing between input resolution to output timing for panel
( output timing from GMZAN1 chip) as follow :
RESOLUTION( from PC or chroma)
PCLK(U200.44) PHS ( U200.74) PVS (U200.73)
640X480 @60 Hz 31.25MHz 50.4 KHz 60.09 Hz
640X480 @70 Hz 35.56MHz 55.93KHz 69.83 Hz
640X480 @72 Hz 36.76MHz 57.64KHz 71.94 Hz
640X480 @75 Hz 37.71MHz 60.12KHz 74.96 Hz
800X600 @60 Hz 28.65MHz 48.45KHz 60.39 Hz
800X600 @70 Hz 32.94MHz 56.05KHz 70.03 Hz
800X600 @72 Hz 34.25MHz 57.61KHz 72.04 Hz
800X600 @75 Hz 35.71MHz 60.10KHz 75.08 Hz
1024x768@60 Hz 28.57MHz 48.36KHz 60.09 Hz
1024x768@70 Hz 32.77MHz 56.05KHz 70.03 Hz
1024x768 @72 Hz 33.97MHz 57.60KHz 71.84 Hz
1024x768@75 Hz 5.41MHz 60.24KHz 74.96 Hz
NG, still no
screen
NG
OK
Check CN303 pin 3 = 5 V ? ( that is
Backlight controller, On-state= 5V)
Check CN303 pin 4
•
4.6V ??(that VR is for
Backlight luminance control)
Replace PANEL, maybe the lamp or
Driver board was bad
OK
TURN VR until CN303
Pin 4= 4.7 V??
NG
OK
Press on-off key once, make-sure Led is in
Green state .check panel-VDD = 3.3V for
HANNSTAR
And 5V for CPT-panel , measured Panel-p
(pin 4,5 from CN201)??
If JP211 was connected, check PPWR relative circuit
( R400,R401,Q250,R223,Q200,R224,R225,C245,Q201
cold-solder or open loop)?? make-sure LED in
Green-state, and PPWR (U200.pin 76)= high 3.3V
If JP212 was connected, check Backlight_En relative circuit
(R223,Q200,R224,R225,Q201,C245), make sure
Backlight_En = low 0V ??
NG
If JP300 was connected ,check Pbias relative circuit( R314,R309,R315,
Q303,Q304,R311 cold-solder or open loop)?? make-sure LED in
Green-state, and Pbias (U200.pin 75)= high 3.3V
If JP301 was connected, check Panel-en relative circuit( R315,Q304
R311 cold-solder or open loop ??) make-sure LED in green-state
And Panel-en= low 0V ??
If JP300 was connect, replace GMZAN1
Chip, if JP301 was connect , replace MCU
NG
OK