Panasonic Viera TC-P54Z1, Technical Manual

Page: 78 / 93

Slide #78
Troubleshooting 11 Blinks Error Code
The ventilation fans are monitored to be sure they are operating properly. If one of the fans stops or its
resistance increases, the resulting current change is applied to pin 61 of the main CPU.
The fan drive circuit is located in the A board.
The Panel-Main-On command from pin 70 of the Panel MPU (IC21100) turns on the fan control ICs
(IC5900 and IC5902).
An increase in temperature of the TV is detected by the temperature sensor (IC2100). This IC
communicates with the main MPU (IC21100) through the Peaks IIC1 bus line.
To control the speed of the fan, a Fan-Max command from pin 60 of IC21100 is output to the fan
control ICs in the PB board. (IC5901 and IC5903)
To keep the unit cool, the fan control voltages from IC5900 and IC5902 range between 7.2V and 11V.
IC5900 supplies voltage to drive fans 1, 2, 5, 6, 7, 8, and 9.
IC5902 supplies voltage to drive fans 3 and 4.
If the output of IC5900 exceeds 12V, the diode (D5901) conducts. The resulting voltage is applied to
pin 60 of IC21100 to trigger the SOS condition. The TV shuts down and the power LED blinks 11
times.
If any of the fans becomes defective and stops or the fan connector is removed, A high is output at pin
3 of the fans connector to forward bias the inline diode. The DC output of the diode is provided to pin
61 of the MPU (IC21100) to trigger the SOS condition.