First turning on the power supply, if the tape in and out of the warehouse or in any way operation can find main shaft motor moment has a tendency to perform an action, display is normal, is forced to terminate the operation for automatic shutdown. Power indicator light goes out after shutdown, need to open the power switch again repeated the above phenomenon. In operation, it found that there is a special law, involving the operation of the motor running to make power supply automatically shut off, and the moment and display disappears phenomenon; At this point, if the multimeter to measure various voltage, found a large swings in front of the screen out instantly, voltage drop 20% ~ 20%. This shows the power load capacity is insufficient, the problem in two aspects of power supply and load or one of them. WDCservice manual download site
 WDCservice manual download site
Check the power supply, found that although the temperature is higher at work, but the relevant testing point waveform and voltage are normal. Considering the power and load capacity related to four things: 1) power supply IC IC1101 (STR1816) bad; 2) the over-current protection circuit control, may be associated with negative load or misoperation. 3) rectifier bridge pile K1102 (S1W1816) resistance is larger or other performance degradation; 4) the first level filter capacitor C1108 power (82 u F / 82 v) capacity is insufficient. Considering the related to temperature and boot for a period of time to restore normal components only two, one is IC1101, another is C1108. So first measuring C1108, find its capacity only about 1/3 of the nominal value, normal use digital capacitance meter measured values should be slightly larger than the standard number. So, its replacement, fully restored to normal immediately.WDCservice manual download site