The AVK200 home theater amplifier machine does not workj9Bservice manual download site
A power amplifier in the professional stage, AV power amplifier is rare, the share of a AV machine fault repair. The failure performance of the whole function keys are failure, the channel output is no show. The cause of this fault is generally the power circuit is not normal or the system control circuit damage.j9Bservice manual download site
Maintenance, the power transformer should first check the primary loop fuse. If the fuse, can be used with the same specifications of the fuse, or more secure with electric light bulbs instead of electricity, no abnormal re installed fuse. Return to normal operation after replacing the machine,j9Bservice manual download site
That is due to voltage instability, the impact of surge current caused by; if the fuse and quickly fuse that machine in the presence of the short circuit fault should be find out the cause of the malfunction, must not blindly increase the capacity fuse, so as not to expand the scope of the fault. According to the maintenance experience, causing the main reason for the power transformer in the primary circuit fuse power transformer windings are short-circuit, or + 55v voltage rectifying circuit and a filter circuit and short circuit, million available table carefully check all relevant components. The most encountered in maintenance work is the DC short-circuit caused by the power element damage.j9Bservice manual download site
If the transformer primary loop fuse normal, should then measure the system to control the microprocessor PIC16C73 (20) pin +5V normal. If no +5V voltage should be checked 7805 feet with no voltage. If foot and no voltage, should check the 3f6 (1a) whether the fuse fuse, or 9V winding open circuit, 1A full bridge damage and leakage of 3C23; if pin voltage is normal, it is 7805 damage or + 5V load short circuit, should check 3C28, PIC16C73 and at24c01 and other damage. If the +5V voltage is normal, PIC16C73 damage or 8MHz crystal quality. When these operations are normal, the input audio signal can be used to track the signal of the oscilloscope, and measure the working status of the output relay, and ultimately find the cause of the failure..

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