A preliminary judgment fault in the timer operation microprocessor IC7501 / MNI4824VTU or peripheral circuits. With a multimeter to check IC7501 37, 38 feet are no voltage, normal should be 1.8 V and 4.6 V respectively. Using oscilloscope to observe 36 feet no 4.1175 MHz/VP - 2.5 P clock oscillation waveform, check the IC7501 foot of the road resistance found no abnormalities, welding crystals under X7501 inspection found no obvious problems, replace 4.1175 MHz crystal vibration after the troubleshooting.n3Kservice manual download site