Open the rear cover, check the power supply board (model NPX805MS2), observe the circuit board without lightning traces. Try boot test, power plate with the sound of the relay, but then click is obviously due to the protection and disconnect at this time observe indicator appears 10 under the intermittent flashes, flashing 10 stops for 3 seconds, then flash 10. View this machine for the factory in October 2, 2010, there is no relevant information. Online seek help, users provide the machine's maintenance manual. After reading the manual, this machine flash 10, the fault tip for A board, P board, SC board, SS board, -5VSOS board, board, the main 3.3VSOS, 9VSOS, tuner power SOS has a problem.

Plate P is the power board, initially thought that the plate P exist problems of possibility is larger, through the efforts of found on the data, the judge P plate quality: separate test plate P, P25 socket of the fifth, feet, p34 socket, 3 feet are respectively connected to. If the voltage is out of normal power supply, vs side with 200W load. False immediately issued a boot vs in accordance with this method. In the end a 150W lighting false load, remove the P plate is connected to the other line and shorting P25 socket 5, two feet, p34 socket, 3 feet (that is, the original host power switch), electricity, lighting bright lights, measuring vs voltage for DC 210v about measuring other 15V low voltage is normal, so the judge P in normal, excluding the P board fault may (Note: with lighting load, time shoulds not be too long, general lighting work voltage is 220V AC, and vs voltage for DC 210v around the bulb damage).

Then on SC board (scan driver board), SS plate (to maintain the drive plate) were measured in high power diode and field effect tube, did not find short circuit breakdown phenomenon, finally will focus on the maintenance of a board (the board). The author has done testing, retain P plate to plate a power supply, cut off the plate P other power supply, and then cut off a plate in addition to the indicator light connected sockets of all other socket, the boot, indicating lamp is 10 under the intermittent flashes, so the judge a plates in the presence of the possibility of failure is high. But the A board is complex, a wide variety of low voltage power supply, and a power on the TV immediately in the protection of the state, giving the feeling is like a dog biting a hedgehog without a mouth". In the end, a good method is to find a good method: after the switch and the protection circuit of the moment before the action, the measurement of a variety of low voltage is normal.

First of all, the power measurement of 9V A board, A board 9V obtained from 15V by the IC5401 regulator, the moment of starting the measured IC5401 9V output voltage is normal, after the fall of OV, judge 9V power supply should be normal; the memory IC1100 then found next to CPU (circuit diagram marked type TVRR555, the actual use of models for the 24C Series), by measuring the memory and pin voltage is 5V, and in the protection circuit after the action is still 5V, it seems the power supply and standby power supply should be CPU- like the P board directly; and then find another memory IC8950 and the adjacent (the IC1100 model with the same memory, 24C Series) by the foot and measure the power supply at the moment of starting, the voltage is very low, only a pointer movement, which makes the author pleasantly surprised, is this the foot power line problems? The foot on the ground resistance measurement under the condition of shutdown, that actually is 0 ohms, short-circuit fault obviously, it seems from the truth is getting closer.

Carefully check the IC8950 power supply line (see above diagram), the power supply process for 20 feet coming from the plate P 15V power supply by A6 socket 9 feet sent to IC5601. After IC5601 regulator output and SUBl.5V SUB3.3V two groups of power supply, IC8950 mentioned above and eighthly, foot power supply is SUB3.3V that SUB3.3V of short-circuit, so temporarily not consider line SUB1.5V. IC5601 peripheral circuit is shown in the figure, the boot pin 20 of the measuring IC5601 in the boot of instant 15V power supply that the front of 15V power supply is normal. IC5601, C5641, C5642, C5643, Q5605 and other components are not found to be abnormal, which proves that the SUB3.3V power supply circuit is normal, and the short circuit fault should exist in the load circuit. See the diagram of the SUB3.3V power supply, the load, the sound circuit of Q2301, IC8950, IC8921, IC1100 and D5486 etc.. Check the element is short, do not have all being removed for inspection, such as in front of IC8921 have insurance resistance L8920, can be disconnected from the L8920 to check IC8921, no insurance resistance, used to most or a knife zoned off circuit board to check, trouble free and then welding, to avoid repeated disassembly and lead to the occurrence of secondary fault. The load of the SUB3.3V is checked all over again, there is no short circuit fault, is the middle line itself has a short circuit phenomenon? With this motherboard in a daze, suddenly found the motherboard SJ card slot as if there is something, look carefully, the original is a dime coin, the removed after testing. SUB3.3V of short circuit fault disappear, it seems this is looking for. The motherboard and the cable connected after the test machine, the blue lights flashing a few screen finally appeared, returning to the image, and then good signal test normal. The power indicator lights flashing state and the corresponding circuit board corresponding to find, see below.