After careful study of the drawings , and finally found the fault "secret" lies, that machine has power supply initialization control circuit , as shown in the accompanying drawings. The control principle is: the power switch S801 has a linkage with micro switch , here temporarily called S801-2. Each time you use the power switch to boot , will make micro switch instantly S801-2 is turned on again , +5 V voltage through Rll24 limiting , Cll08 filtering and Rll22, Rll23 partial pressure to the Q1105b pole, so Q1105, Ql 104 have instant conduction, negative pulse signal output pin to the CPU18 16,19 feet , CPU will EAROM the power control code is initialized to "ON" state, that is a direct boot. If the remote shutdown during normal viewing , the CPU of the EAROM automatic power control code rewritten to "OFF" , the standby state , it can not be directly next boot. Because of the characteristics of the CPU is the precedence that end at the next boot power control codes when the last shutdown , it must at the time of the shutdown of the "OFF" code erased and rewritten as "ON", in order to ensure that the next boot directly . Erase and rewrite the same task performed by the circuit . Power switch is pressed at shutdown , S801-2 again instantly turned , Q1105, Q1104 have instantly turned on , CPU18 + negative pulse signal output to the 16 foot , feet , EAROM the power control code again initialized to " ON " state , and the preservation of the control code down, the next time you press the power switch can directly boot up .c7kservice manual download site

    According to the analysis of the above-mentioned principle , at boot and shutdown Q1105 b measuring voltage , the Ministry is the instantaneous voltage of less than 0.1V, checking each element between S801-2 to Qll05 b pole, found C1108 (10μF/16V) serious leakage, replacement of a capacitor with troubleshooting models .c7kservice manual download site

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