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Service Hints & Tips |
Document ID: YAST-3NYSY7 |
IBM Monitors - Jitter in high resolution mode
Applicable to: World-Wide
Symptom:
Some users may perceive apparent flicker or jitter when using either the 8514/8515/8516 monitors in high resolution mode (1024 x 768) only. Some application packages, such as CAD software, intensify this effect. The effect is also visible, while running advanced diagnostics, by selecting the monitor adapter 8514/A Test, and viewing the 1024 x 768 test pattern (reference 1 inch block of horizontal lines).
This perceived flicker/jitter effect is due to the interlace design of the monitor refresh. This is a characteristic of interlaced monitor and does not indicate a defective monitor.
Problem Isolation Aids:
Perceived jitter is due to the way that the human visual system interprets discrete, sequential images (such as seen in cinematography) as smooth and continuous. Perceived jitter is not due to actual movement of the image, but instead to the rate of refresh.
To determine if there is movement within the image:
1. Examine the image at close distance (approx. 3 to 4 inches) or with a magnifying device. To confirm/deny that the jitter is real.
2. Interlace modes are more susceptible to interference caused by magnetic fields radiated by other equipment and care should be taken to determine that magnetic interference is not a problem. (eg. increase the separation or turn off the other equipment).
3. If actual jitter is found, the problem is real and the defective FRU should be determined by normal defect determination methods.
Fix:
The following steps will minimize the effect:
- Reduce the Brightness of the image
- Reduce the contrast between the foreground and background
- Avoid horizontal single pel lines
- Use reverse video images (black on white).
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Hint Category |
General Information | |
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Date Created |
05-04-94 | |
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Last Updated |
20-01-99 | |
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Revision Date |
20-01-2000 | |
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Brand |
IBM Monitors | |
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Product Family |
Personal System/2 | |
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Machine Type |
8514, 8515, 8516 | |
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Model |
Various | |
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TypeModel |
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Retain Tip (if applicable) |
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Reverse Doclinks |