In to a CEP - 321 Hitachi color TV with the remote control and replace the supplement in the process of the high-frequency tuner, due to the supplement high-frequency head installed on the remote control circuit board, the original machine between the antenna socket and high-frequency head cable is too short, so ma chine to cable TV antenna plug plug directly into the supplemented by transform high frequency head. After the electricity, the circuit board on the red light flash, and with "pa" a sound, then acoustic image. Power visual inspection, found that the power fuse blackened and fusing, high-frequency head and channels of the 12 v power cord to the power supply and ground wire of copper foil burn out. Measured with a multimeter to check the relevant circuit, the power supply has two diode breakdown in the rectifier bridge, the new change of supplement high-frequency head, into the integrated block (HA1140A) damage. Replace the damaged components, and to burn out circuit copper foil, carefully check without apparent short circuit phenomenon. Don't put antenna electric commissioning, has a grating noise and yellow, as decoding integrated block (M51393AP) has been damaged, change new, color grating returned to normal. yXkservice manual download site
 yXkservice manual download site
 yXkservice manual download site
In order to check the received signal, and cable TV antenna plug in. Line inserted into the high-frequency head on the day of the moment, the red light flashing between antenna plug and socket, and heard a sound of "pa", smoking on circuit board, light and sound again. yXkservice manual download site
 yXkservice manual download site
This time just know cable TV antenna can not attached directly to the hot plate high-frequency head! yXkservice manual download site
 yXkservice manual download site
Cable TV antenna, because of technical requirements, shield connected to the earth, and the mains zero line is connected to the earth. yXkservice manual download site
 yXkservice manual download site
Hot plate television line is connected to the 220 v mains. When the cable TV antenna into the high-frequency head, equivalent to the ground and 220 v mains short sub, 220 v mains through the circuit board and the discharge of the television, burn out circuit.

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