6/2/2023 0 Comments Onedrive psuAs before, all of the DC voltages at this chip seemed reasonable enough, but the pin that was measuring AC voltage from the transformer was showing the same ripple visible on the 12 VDC line.Įven more digging uncovered that the transformer itself had a control IC nestled away. Connecting all the dots.īy carefully following traces and comparing with common PSU diagrams, was able to identify the SG5616 IC that checks the various voltages being produced by the PSU and generates the PWR_OK signal which tells the motherboard that everything is working normally. A quick look at the PSU output with a voltmeter showed things weren’t too far out of spec, but putting an oscilloscope on the 12 V line uncovered a nasty waveform that demanded further investigation. Eventually, noticed a restart before the operating system even loaded, which confirmed the hardware was to blame. The first sign of trouble was when the computer would unexpectedly reboot with nothing in the system logs to indicate a problem. Which is why this deep dive into a failed ETK450AWT by is worth a look. But even if we all intuitively know at this point that bad caps are almost always the culprit when a PSU gives up the ghost, it’s not always easy to figure out which one is to blame. It’s a bad power supply, of course it was capacitors to blame.
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