Panasonic TC - D25C color TV with the remote control to turn it off and then shut off the POWER switch, the next time can't directly a boot, need to press the "POWER" button on the remote control to e |
| Time£º2014-05-28 10:07:23 Source£ºNetwork Author£ºUnknown Clicks£º1275 |
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GtNservice manual download site
GtNservice manual download site
After careful study of the drawings, finally found the fault of "secret", namely the machine is equipped with switch on the power supply to initialize the control circuit, as shown in the appended drawings. Its control principle is: on the power switch S801 always has a linkage with the micro switch, here is called S801-2. Every time with the total power switch boot, will make the micro switch S801-2 ON a moment, + 5 v voltage by Rll24 current-limiting, Cll08 filter and Rll22, Rll23 partial pressure to Q1105b, instant Q1105 Ql, 104 have been conduction, CPU18 feet output negative pulse signal sent to the 16 and 19 feet, the CPU will power control code of EAROM initialized to "ON" state, namely direct a boot. If the remote control to turn it OFF in the normal watch, the CPU power control of EAROM code automatically to "OFF" the standby mode, it cannot be directly next time a boot. Again because the CPU is the feature of shutdown at the next priority last when the phone is switched ON when the power control code, so must be turned OFF when the "OFF" code for erasing and rewriting to "ON", in order to ensure that the next boot directly. Erase and rewrite the task as completed by this circuit. Power master switch press during shutdown, S801-2 again instantly connected, Q1105, Q1104 have instant conduction, CPU18 + feet output negative pulse signal sent to the 16, feet, power control code of EAROM initialized again "ON" state, and the control code, directly ON the next press power master switch. GtNservice manual download site
GtNservice manual download site
According to the analysis of the above principle, the boot and shutdown when measuring Q1105 voltage, b is not instantaneous voltage of 0.1 V, check S801-2 to Qll05 b pole between each element, found C1108 (10 u F / 16 V) serious leakage, replacement of a same capacitance after troubleshooting.GtNservice manual download site
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