Panasonic TC-P50VT20 Technical Manual page 80

1 Blink SOS: Communication error between System CPU (IC1100) and Panel CPU (IC9003).
2 Blinks SOS: Pin 62 of the CPU IC9003 monitors the 15V line. During normal operation, the pin 62 is
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: IC9802 is a 3.3V regulator located on the D board. Its output is monitored by IC9003. If
the 3.3V is not present at pin 61, the MPU shuts down the unit. The power LED blinks 3 times.
4 Blinks SOS: When an over voltage condition of the voltage lines from the power supply occurs, pin
16 of IC701 goes high. This high is provided to pin 67 of IC9003 of the D board triggering the "POWER
SOS" circuit. When this happens, the TV shuts down and the power LED blinks 4 times.
5 Blinks SOS: Pin 60 of the CPU IC9003 monitors the 5V line. During normal operation, the pin 69 is
high. If the 5V line is missing or shorted, a low is provided to pin 60. As a result, the unit shuts down
and the power LED blinks 5 times.
6 Blinks SOS: Pin 65 of the CPU IC9003 monitors the status of the SC board. During normal
operation, a low is applied to pin 65. If the SC board becomes defective, a high is provided to pin 65.
As a result, the unit shuts down and the power LED blinks 6 times.
7 Blinks SOS: Pin 68 of the CPU IC9003 monitors the status of the SC, SU, SD board. During normal
operation, a low is applied to pin 68. If the SC, SU, or SD board becomes defective, a high is provided
to pin 68. As a result, the unit shuts down and the power LED blinks 7 times.
8 Blinks SOS: Pin 66 of the MPU IC9003 monitors the status of the SS board. During normal
operation, pin 7 of connector SS33 outputs a low to pin 66. If the SS board becomes defective, a high
is provided to pin 66. As a result, the unit shuts down and the power LED blinks 8 times.
Another SOS Detect circuit in the Sustain board monitors for physical connection between the SS
board and the panel. If any of the flex-cables from the panel is not connected or is not properly seated,
a high is provided to pin 66 of the CPU in the D board. When this happened, the TV shuts down and
the power LED blinks 8 times.
9 Blinks SOS: Pins 85 and 86 of the MPU IC9003 monitor the status of IC9300 and IC9400. During
normal operation, pin 85 and pin 86 are low. A malfunction of IC9300 or IC9400 triggers a shutdown
and the power LED blinks 9 times.
SOS Detect Circuit
Slide 80 Slide 80