Hitachi 46W500 Training page 9

DP-3X LED (Visual Trouble Detection) CIRCUIT EXPLANATION
STAND BY POWER SUPPLY
This explains the LED used for Visual Trouble Shooting Circuit Diagram explanation:
(See DP-3X LED (Visual Trouble Detection) Diodes for Stand By Power Supply Diagram for details)
1 GREEN
In the DP-3X chassis, there is 1 Green LED in the Stand By power supply.
Use this LED to determine if the set is experiencing a problem.
The LEDs can be used in the following ways.
OFF:
•
If the LED is off, then the power supply that is being monitored is unavailable. (Excluding the possibility
that the LED itself is malfunctioning).
•
If the LED turns on but then quickly goes off, then the power supply that is being monitored can be sus-
pected.
ON:
•
If the LED is on, then the power supply that is being monitored is working normal. (There is the possibility
that the power supply being monitored may in fact be present but low. If after making visual inspection and
all seems OK, but there's still a problem, be sure to check the accuracy of the power supply in question.
GREEN LED D913.
D913 (Stand By +5V)
•
Monitors the Stand By +5V output from U901 pin 1.
•
This is a new IC in the DP-3X chassis. It is a self contained DC-DC converter that provides the Stand
By +5V which keeps the necessary circuits alive when the set is turned off. Such as the Microprocessor,
etc.....
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