Plus electric instantaneous power indicator light is lit, the vibration switch power supply, then the lights went out, it is stopped, it shows that the load has a short circuit or switch power supply itself is out of order. Will load disconnect, with 40 w / 220 v bulbs give false load, then add electricity, the power will be able to start up. In addition to the low - 12 v output, the rest of the 70 v, 13 v, 56 v output is normal. To this seem to be should determine the line scan circuit fault, and so on the line scan circuit to carry on the careful screening, found no abnormalities, searched almost all related to the line of circuit elements are no results. Then on again to check the power supply, power supply with low load capacity? What why can make 220 v / 40 w (or 60 w) light bulb, and the output voltage steady? Inspection on the power part of the related components, but did not find out obvious problems, is the power supply module IC601 (DP104C) performance is bad? Try to use a new power supply module (DP104C) replacement IC601, electrical commissioning, everything is all right. B5nservice manual download site
 B5nservice manual download site
 B5nservice manual download site
Note: this is a typical fault, in the actual maintenance has encountered many sets of the same failure phenomenon, are IC601 (DP104C) improper performance.B5nservice manual download site