Panasonic Viera TC-P54Z1, Technical Manual

Page: 80 / 93

Slide #80
12 Blinks Error Code
Sound processing and adjustments are performed by IC24510. The 4 channels PWM audio output of
the IC is applied to the 2 audio power amplifiers (IC22301 and IC22302). The PWM signals of the
power amplifiers are output to the right and left channel speakers for sound reproduction.
D22017 monitors the audio power amplifier ICs (IC22301 and IC22302) for excessive current drain. If
any of the 2 ICs or one of the speakers develops a short circuit, a high is output to turn on Q22022.
When Q22022 is on, a high is applied to pin 27 of the System MPU (IC21100) triggering an SOS
condition. Then unit shuts down and the power LED blinks 12 times.
A short circuit of the 15V line causes the diode D22014 to go into conduction. The base voltage of
Q22022 becomes low and a high is output to pin 27 of IC21100 triggering a 12 blinks SOS condition.
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