1: Communication insurance canal burns black blast to crack, detect BD1 comes BD4 4 commutate diode, assist canal of stabilized voltage of dynatron of switch of Q15 of power source circuit, ZD8, short circuit of puncture of diode of D30, D41, r72 of current limliting resistor opens circuit. Change afore-mentioned component, power source of the ATX that start returns to normal. The C of Q15, E is extremely embedded damp diode, its replace model to be 2SC2979, 2SC3148, 2SC3178. Exemple 2: Bide one's time, when the condition that start, PS-ON, PW-OK all is low n, the 12 feet that check TL494 of chip of wide modulation of IC1 arteries and veins have voltage input, 14 feet do not have output of stabilized voltage 5V, after cutting off the power online measure 14 feet to be almost to ground block value 0, suck the 14 feet that unplug circuit board IC1 is measured after TL494 since stannum to be in to ground block value 3k Ω above, normal. Electrical outlet of on solder 16 feet, when be being replaced with another TL494, electrified and controlled the fan after starting turned to stop namely, fan of power source of the switch after starting can jiggle, circuit of circuit of wave of filter of commutate of demonstrative communication input, auxiliary power source is normal, breakdown controls circuit to reach in wide modulation of arteries and veins commonly drive class, automatic stabilized voltage and protective control circuit. Detect component is normal all round IC1, the hand feels IC1 chip hair to iron, measure 14 feet again right short circuit, change a few TL494 repeatedly, the chip after the electrified power source that start is not to send iron even if fumy blast is cracked, microscope replaces the chip below, discover pin is crossed by new dip stannum, doubt is to tear open the face-lifting of parts to taste. Change the quality goods TL494 of an ecru pin afresh, electrified it is normal to measure. Common breakdown of IC1 of power source of galactic ATX switch is 12 feet, 14 feet right short circuit, 12 legs are right short circuit of 11 feet puncture. Change IC1, should beware this parts of an apparatus is pin is tasted by the face-lifting after dip stannum, this kind of chip often causes TL494 electrify burn down, blast to crack, or cause ATX switch power source to work a few days bad, but the breakdown of * sex extreme difference. Overhaul the ATX switch power source after, should mix by certain interval the frequency is factitious short receive, disconnect the PS-ON of 14 feet and ground connection carry ATX outlet, in bide one's time, power source of ATX of the check below the condition that start works but * sex. Exemple 3: Transformer of T3 of circuit of auxiliary power source is sub short circuit of puncture of rectification diode BD6, IC1 bursts apart, BD6 commutate output is the 12 feet to IC1 provide input power source, BD6 short circuit, sub alternating voltage increases auxiliary power supply directly cut is on TL494 chip, cause breakdown. Change attaint component, in bide one's time, signal of PS-ON, PW-OK, 5VSB is measured below the condition that start, ATX power source outputs voltage all normal. Exemple 4: Of IC1 11, 12, 14 legs are right ground short circuit, pulse T2 of power transformation circuit drives half bridge winding oscillation is in charge of transformer short circuit of puncture of the B of Q3, E pole, blast of C16 of capacitance of wave of T3 sub filter cracks transformer of auxiliary power source. The discovery in the overhaul, when the 14 feet interior when IC1 opens circuit to be outputted without stabilized voltage 5V, voltage of output of commutate of T3 sub BD5, BD6 is elevatory, c16 is nominal compression is worth 16V, extremely easy flee in terrorfry in deep fat or oil is cracked explode housing, at the same time TL494 puncture short circuit. With nominal the capacitance of above of compression value 25V is replaced, change after IC1, Q3 is in charge of, power supply is normal. IC1 attaint is replaced besides the chip that can use 494 series outside, still can use TL594, IR3M02, MB3670, ULN8186, ULS8194R to wait to be replaced directly. Breakdown phenomenon 2: ATX switch power source is received advocate board, signal of the PW-OK after starting constant low, lead plane cannot enter Windows picture. Online measure ATX outlet signal of 8 feet PW-OK is 0.7V low n, dc stabilized voltage is outputted. Sky of ATX power source carries, controlled tall n of the PW-OK after starting, breakdown is belonged to it is normal to carry for nothing, to load is unusual. PW-OK signal changes by Q21 E extremely potential is definite, try change Q21, C60 to disable, change C32 hind is normal. Breakdown phenomenon 3: ATX power source just received town report, without starting, fan turns sometimes stop namely, the instant has dc stabilized voltage to output. Put through town report, bide one's time condition is online measure WL431 of circuit of IC10 accurate stabilized voltage, uk potential discretion is flabby, bring about PS-ON to control signal unusual, change C49, C51 is invalid, it is normal to replace IC10 hind.
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