(1) the multimeter to measure IC681 attending foot voltage 0.5 V, normal, using the oscilloscope to observe the feet, no stimulation waveform, suggests that fault. IC681 10 feet before a push or oscillating circuit. ainservice manual download site
ainservice manual download site
(2) measuring IC701 12 feet voltage of 10.3 V, the power supply voltage is normal. Check the oscillator R602 peripheral component, R603, C604, are no exception. Doubt is IC701 internal damage. ainservice manual download site
(4) new LA7801 scanning, machine back to normal. ainservice manual download site
(5) under the condition of no oscilloscope, also can use multimeter dB gear measuring IC701 attending foot presence of ac voltage, to determine whether to start up.ainservice manual download site
|