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MacBook (13-inch) Troubleshooting — Symptom Charts 331
Display Issue: When displaying a single color over the screen area,
the LCD panel shows one or more pixels that are not properly lit
To determine whether or not the display has an acceptable number of pixel anomalies, follow the
steps below:
Set the display image to one of the following colors: all-white display, all-red display, all-green
display, or all-blue display. Knowledge Base article 112125: “Service Diagnostics Matrix”, has
the LCD Tester Diagnostic Utility that will generate these patterns on the screen.
Using a jeweler’s loupe, pocket microscope, or other magnifying device, identify and count
each pixel anomaly:
• Bright subpixel anomaly = subpixel that is always on
• Dark subpixel anomaly = subpixel that is always o
The number of acceptable pixel anomalies for this computer is:
Acceptable Number of Subpixel Anomalies
Bright Up to 3
Dark Up to 5
Combination Up to 7
If the number of subpixel anomalies exceeds the acceptable number listed in the above
chart, replace the LCD panel.
Replace the LCD Panel if...
Bright 4 or more
Dark 6 or more
Combination 8 or more
If the number of subpixel anomalies is acceptable, explain to the customer that the pixel
anomalies are within specications, and no repair is necessary.
Important: Do not release the specications to customers. Instead, inform them that a certain
number of subpixel anomalies are considered acceptable, and these factors apply to all
manufacturers using LCD technology—not just Apple products.
When speaking with customers, please use the following explanation:
Active-matrix LCD technology uses rows and columns of addressable locations (pixels) that
render text and images on screen. Each pixel location has three separate subpixels (red, green,
and blue) that allow the image to be rendered in full color. Each subpixel has a corresponding
transistor responsible for turning the subpixel on or o.
There are typically millions of these subpixels on an LCD display. For example, the LCD panel used
in the Apple Cinema HD display is made up of 2.3 million pixels and 6.9 million red, green, and
blue subpixels. Occasionally, a transistor does not work perfectly, which may result in the aected
subpixel being turned on (bright) or turned o (dark). With the millions of subpixels on a display,
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