Non-Failure Symptoms - Pioneer PDP-507CMX Service Manual

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5.4 NON-FAILURE SYMPTOMS

1. Function of lowering the luminance level (Information on symptoms that are not failure)
High-temperature protection function
If the temperature reaches 70 °C, the limit of the maximum count of plasma discharge is gradually lowered, in order to prevent overheating.
• Temperature control is performed based on the temperature value of TEMP1.
• The maximum count of plasma discharge is decreased by 8 every 5 seconds.
• The lowest limit of the maximum count of plasma discharge is about 700.
• The maximum count of plasma discharge will increase gradually once the temperature of the unit is lowered to a specified temperature.
Panel protection function 1 (for preventing burn-in during Still Picture mode)
If Still Picture mode is continued for 3 minutes or more, the limit of the maximum count of plasma discharge is gradually lowered, in order to
reduce burn-in on the display.
• Whether the image displayed is a still picture or not is detected, and the Panel Protection Function will be activated (Even if the mouse
pointer is moved on a still picture, that picture is judged as a still picture.)
• The maximum count of plasma discharge is decreased by 8 every 5 seconds.
• The lowest limit of the maximum count of plasma discharge is about 700. (It takes about 15 minutes to reach the lowest limit, although it
depends on what is displayed on the screen.)
• If the image is changed to an animated picture, the maximum count of plasma discharge is gradually increased.
Note:
How to lower the luminance level is the same as that for the high-temperature protection function 1.
Panel protection function 2 (for protecting the SCAN IC)
If a particular load is added on the SCAN IC locally, as shown in the figure
on the right, the limit of the maximum count of plasma discharge is
gradually lowered.
Note:
How to lower the luminance level is the same as that for the high-
temperature protection function 1.
Panel Protection Function 3
(for protecting the panel from cracking)
The heating value for a bright window part on the screen, as shown in the
figure on the right, is high. So, if such a pattern is recognized, the limit of
the maximum count of plasma discharge is gradually lowered.
Note:
How to lower the luminance level is the same as that for the high-
temperature protection function.
2000
700
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High-temperature protection
function 1, 2, 3
The maximum count of plasma
discharge is decreased if the
unit reaches 70°C or higher.
APL (average picture level)
PDP-507CMX
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7
Example: A display with which the SCAN IC
protection function is to be activated
Example: A display with which the panel-
cracking protection function is to be
activated
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8
A
B
C
D
E
F
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