VIFA VIFA HF (I) power amplifier not sound a case of maintenance, the amplifier maintenance process: disassemble observation machine no maintenance traces, turn on the power switch after switching on the mobile phone touch bright key, press the touch button does not move (the machine boot method to hold down the power button for about three seconds), main relay voice heard, but on the left side of the display does not shine.us9service manual download site
Will audio signal access power amplifier of any channel, panel in the middle of the current indicator flashing, indicating that the pre detection signal to normal. The machine has two transformers, a small inverter for standby power supply, 5 volts and plus or minus 12 volts, for the first grade and the boot circuit used to measure these normal voltage. The relay can also explain the relevant circuits are normal.. Therefore machine power amplifier board in the level before the board below, it is not convenient to measure voltage, but level before the board of bile circuit power supply is provided by the main transformer, so relay measurement main transformer output to common circuit of power supply.us9service manual download site
The marked 19 V and 225 V are not, and the main transformer is not working. Remove the power amplifier board after examining the inverter without open, check the main relay contact has been oxidized black, after the replacement of the test machine, bright screen, the work of the normal voice, fine listening to the sound a murmur is abnormal, observed after filter capacitor voltage all drum package, removed light light shake inside are indistinct and change after all the filtering capacitance test machine voice returned to normal.us9service manual download site
The VIFA this HF (I) power amplifier design atmosphere, see appearance very grade, disassemble see circuit materials and workmanship, also can regarded as a leader in domestic machine. However, from this case of failure or can be seen, compared with the imported machine, there is a lack of material, the price is no import brand expensive.

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