Dell P780 - 17" CRT Display, Service Manual

Page: 9 / 61

— 9 —
P780
Damper Wires
Geometric Distortion
Screen not sized or centered correctly
•
Perform monitor reset
•
Ensure monitor is in proper video mode
•
Adjust the appropriate geometric control
Moiré (Thin Curvy Lines)
Screen has wavy or elliptical lines Screen has wood grain patterns
•
Ensure monitor is in proper video mode
•
Adjust size first then the moiré controls
Horizontal/Vertical Lines
Screen has one or more lines
•
Perform monitor self test feature check
•
Check for bent or broken pins
•
Horizontal lines could be damper wires
Sync Problems
Screen is scrambled or appears torn
•
Perform monitor self test feature check
•
Check for bent or broken pins
•
Boot up in the "safe mode"
Audible
Noise
Problems
Has humming sound or high frequency squeal
•
Ensure monitor is in proper video mode
•
Reposition the monitor
•
Loud hum when turning on is normal
CRT Scratched
Screen has scratches or smudges
•
Turn monitor off and clean the screen
Safety
Related
Issues
Visible signs of smoke or sparks
•
Do not perform any troubleshooting steps
•
Monitor needs to be replaced
Intermittent
Problems
Monitor malfunctions on & off
•
Ensure monitor is in proper video mode
•
Perform monitor reset
•
Perform monitor self test feature check
PRODUCT SPECIFIC SYMPTOMS
SPECIFIC SYMPTOMS
WHAT YOU SEE
POSSIBLE SOLUTIONS
Two fine lines on the screen.
Two fine horizontal lines (wires) are visible.
These damper wires stabilize the vertically striped aperture grille. This aperture grille allows more light to pass through to the screen giving the Trinitron CRT more color and brightness
The
following
table
contains
general information about common monitor problems you might encounter.
COMMON SYMPTOMS
WHAT YOU SEE
POSSIBLE SOLUTIONS
No
Video/LED
off
No picture, monitor's dead.
•
Check connection integrity
•
Electric outlet verification
•
Ensure power button depressed fully
No Video/LED on
No picture or no brightness
•
Increase brightness & contrast controls
•
Perform monitor self test feature check
•
Check for bent or broken pins
Poor
Focus
Picture is fuzzy, blurry or ghosting
•
Eliminate video extension cables
•
Perform monitor reset
•
Decrease brightness & contrast controls
•
Lower video resolution or increase font size
Shaky/Jittery Video
Wavy picture or fine movement
•
Perform monitor reset
•
Check environmental factors
•
Relocate and test in other room
Color
Purity
Problems
Color is not uniform
Has color blotches or shades
•
Perform
degauss
•
Perform monitor reset
•
Check environmental factors esp. woofers
Color
Convergence
Problems
Characters show red or blue at edges
•
Perform monitor reset
•
Adjust the color convergence controls
Missing Color or Color Flood
Entire screen is purple or yellow Entire screen is red, green or blue
•
Perform monitor reset
•
Perform monitor self test feature check
•
Check for bent or broken pins
•
Reseat the video card
Missing
Pixels
CRT screen has spots, specs or blemishes on the glass
•
If the blemish is on the outside of the glass, try cleaning the CRT screen
Brightness Problems
Picture too dim or too bright
•
Perform monitor reset
•
Adjust brightness & contrast controls