greetings!!!
can u pls help me point out the trouble in the atx psu i am trying to repair. it powers up but its voltage is lower than its specifications. yellow wires- (only +7.5 volts, should be +12v, red wires - only 2 volts, should be +5 v). what could be the problem and where do i start?
thanks in advance,
ian
Hardly worth messing with, but I would first look at the bridge rectifier to see if one of the diodes opened. A low input voltage could account for low output voltage if it would still worked.
I would check the electrolytic capacitors within the power supply. Use an ESR meter for this, if available. Also look for capacitors where the tops have bulged up. They are bad. John
Under what conditions? In the PC or on the bench? Does it have a load? Is the 115/230 VAC switch set correctly? Did the problem happen on its own or did someone just give you the power supply? Etc.
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how about if the atx psu does not turn on when the green wire-black wire is shorted? should i direct my troubleshooting on the controller circuit for PS# ON or should i check first the primary side of the PSU?
thanks in advance, ian
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