Panasonic Viera TC-P54Z1, Technical Manual

Page: 58 / 93

Slide #58
Panel MPU SOS Detect
• Protection circuits are incorporated in the unit to prevent the failure of a single circuit or
component from creating catastrophic damage.
• A shutdown condition occurs when there is an over voltage, a short or a drop in any of the voltage
lines. Also the shutdown circuit is triggered when the fans are drawing more current than normal
or are not connected.
• Normally the Panel CPU and the System CPU of the DA board detect when a shutdown condition
has been triggered.
• When an abnormality has occurred, the unit’s protection circuit operates and the TV is reset to the
standby mode. At this time, the defective block can be identified by the number of blinks of the
POWER LED on the front of the unit.
• The Panel MPU IC29003 of the DA board detects conditions that make the power LED blinks1, 2,
3, 4, 5, 6, 7, 8, or 9 times.
• The Main MPU IC21100 of the DA board detects conditions that make the power LED blinks 10,
11, 12, 13, and 14 times.
• The number of times that the POWER LED blinks indicates the areas where a problem is
suspected.
• 1 Blink SOS: Communication error between IC21100 and IC29003.
• 2 Blinks SOS: Pin 62 of the CPU IC29003 monitors the 15V line. During normal operation pin 62
is kept high. If the 15V line is missing or shorted, a low is provided to pin 62. As a result, the unit
shuts down and the power LED blinks 2 times.
• 3 Blinks SOS: The P3.3V is monitored by IC29003. If the 3.3V is not present at pin 61, the CPU
(IC29003) shuts down the unit. The power LED blinks 3 times.