Poor Image Quality - ViewSonic VG181 Service Manual

ViewSonic
July 2000 - Version 1.0
Service Manual
VG181
TROUBLE SHOOTING
POOR IMAGE QUALITY
Start
Yas
Too dask or light 7
No
it means image exceed or less than
display area
1. Is scaling in fill all
2. Do auto tune function with full
screen pattern
3. 1s the timing supported
4. Check U1 if digits!
5. Check U9 if analog
6. Check power of PVDD it analog
7. Check rippte (DC-AC) _
1. Do auto tune function with full
screen pattern
2. Is the timing supported
3. Adjust H-size If analog
4. Chock U3 if analog
5. Check power of PYDD if analog
6. Check ripple (DC-AC)
1. Do auto tune function with full
screen pattern
2. Is the timing supported
3. Adjust H/v-position if analog
1, Do auto tune function with full
sereen pattern
. Is the timing supported
3. Adjust phase if analog
4. Check power of PVDD if analog
5. Check ripple (DC-AC)
sy
. Adjust contrast & brightness
. Adjust gamma
. Adjust user A, G, 8
. Check backlight (inverter)
. Check signal between U9 and
P2 if analog
6. Calibrate ADC with pattem that
32 scales of gray if analog
OO & © Pr -4
Page 44
Color unbalance ? es
No
Color interpolate ? uae
No
Confidential - Do Not Copy
1, Adjust user R, G, 8
2. Adjust color temperature R,
GB
3. Check signal between U9
and P2 if analog
4. Catibrate ADC with pattem
that 32 scalies of gray if
anaiog
4. Check signal (U15 to
LVDS)
2. Check signal (U15 to Ut) if
digital
3. Check signal (U1 to P1) if
digitat
4. Check signal (U15 to U9)
if analog
5. Check signal {U9 to P2) it
analog
nee orca 7