& lt
D== sync, corrected by elderman == @elder man{\chffffff}{\ch00ffff} {\chffffff}{\ch00ffff} {\chffffff}{\ch00ffff} {\chffffff}{\ch00ffff} {\chffffff}{\ch00ff00} {\chffffff}{\ch00ff00} {\chffffff}{\ch00ff00} {\chffffff}{\ch00ff00} {\chffffff}{\ch00ff00} {\chffffff} .."alt ="
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& lt
> working principle: when power is added to the power, the auxiliary power starts with the creation of the vref (lm 393, also vref), the three feet of tl 494 provide lower voltage, the triode a733 conductor, and the one foot of lm 393 has a low output level. When the atx power is turned on, the main transformer circuit works, the three feet of tl494 maintain a high level of power, leaving the diode a733 in a cut-off state, and vref recharges through the capacitation (4. 7uf), after a delay, output of the p. G. Signal of +5v, and the mainframe starts work. When the power output voltage is reduced, the detection voltage delivered to tl 494 is reduced, and if the voltage is reduced beyond the rated range, the three feet of tl 494 will be lowered to a low level, the tripolar a733 conductivity will make the one foot output of lm 393 low and the mainframe will stop working. *
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(b) fault clearance: in the case of the above-mentioned malfunctions, check the vref (base voltage) power supply. If the power supply is normal,1 the lm393 integrated circuit is broken, p. G. Signals are consistently low-level, 2-triode a733 short circuits, and p. G. Signal clamps are located at low-level. Due to the low working voltage of this part of the circuit, the resistance element rarely fails. When the damaged component is exchanged more, the malfunction can be eliminated。
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