On Saturday, November 9, 2013 11:17:18 PM UTC-5, Flasherly wrote:
OK. So it wasn't capacitors, which just fine if you say so.

If capacitors cause damage, then included is how capacitors cause damage to other electronics. In generations of design and support, I have never seen such damage. However, if you know how a capacitor can cause that damage, then please explain it.

Many see an incandescent bulb flash and burn out with power on. That proves power cycling damages light bulbs? Not for one minute. Conclusions based only in observation are classic junk science. To have a fact means also learning underlying principles and numbers. What damages light bulbs? Facts are well published even with industry standard equations that define failure. Bulbs fail due to hours of operation and voltage (temperature). Power cycling causing damage only when observation contradicts well proven science.

Same with a motherboard causing PSU failure. Long before PCs existed, all power supply outputs could be shorted together - without damage. Intel's ATX standards even defined how thick that shorting wire should be. A PSU damaged by the load (ie motherboard or shorting wire) was probably designed (or constructed) defectively.

In a market dominated by computer assemblers, then manufacturers can dump inferior PSUs into the market. Many would blame the load (ie motherboard), mythical surges, or 'dirty' electricity rather than a PSU that was defective when manufactured. Blame based only on observation and speculation.

Most failures are due to manufacturing defects. To say more requires identifying a specific reason for each failure. I have done that often to sometimes discover PSUs missing essential functions. Because PSUs are often marketed to people who do not even routinely demand spec sheets with each supply. No spec sheets mean it need not even meet national safety requirements, FCC regulations, or ATX standards. No spec numbers is a first symptom of missing essential functions. It may even self destruct on Intel's 'short all outputs together' test.

What caused a failure? A specific part in conjunction with how PSUs work is required for any valid conclusion. Most every PSU analyzed (by making it functional) failed due to manufacturing defects.

Spec sheets should include spec numbers that say it cannot damage the disk drive or motherboard. Required protection that might be missing IF written specifications do not say it exists. Conclusions only from observation (also called wild speculation) do not say why failures happen. If the PSU is properly designed, then it does not damage disk drives. And the load (motherboard or even a short circuit) does not damage the PSU.

Failing capacitors do not damage electronics. But it does explain strange and intermittent problems that some even blame on a virus (software) or surges. Speculation based only in observation is classic junk science. The load does not damage a properly designed PSU - as was standard long before PCs existed.