In conclusion, this was definitely entertaining, and an extra bonus was that Gamer11705 will, if he can be bothered to wade through the corrections and subsequent irrelevant rebuttals containing nothing of value to find a few tidbits of useful info, much better.
At thing point I'm inclined to declare "troll".
Dude that makes no sense on so many levels... so it's the quality of power and not output of power?
I never meant that. A proper correction would be that the amount of power won't matter if the quality is crap.
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unless the guy has miniscule wires connecting from the psu to motherboard or barely connecting or something that's just not going to be the case.
Not sure what wire size has to do with anything. I'm not talking about RF interference with the power input but rather fluctuations caused by failed components. As an example, my old PC still works fine, but the power supply has issues. This has caused bad sectors and random freezing. I know it's the power supply, because I can swap in my other PCs power supply and it can run for days without showing the symptoms. This is something called "experience". I changed nothing but the PSU, and the problems dissapeared! Why, if there was a problem with the old PSU then it shouldn't have worked at all, but it did.
Even if what you're explaining could happen which I've never heard of or expereinced myself the chances of it happening are rare but so far I've seen about 30 pages like this saying the exact same thing. psu's are just a bunch of capacitors voltage regulators, resistors, diodes a transformer and most importantly a fuse, they're not that difficult however there are a bunch of failsafes in place so that if this fails then everything does...
yes. PSU's consist of a number of components. Components can fail, or have problems. for example, capacitors can acquire wear and tear, and their capacitance can be affected. One possible result might be that the POWER_GOOD signal is sent out to early; or perhaps a Rail is given too much amperage for it's load.
regarding the POWER_GOOD signal:
From: "Upgrading and Repairing PCs, 15th Edition", I'm sure you'll dispute it anyway.
In addition to supplying electrical power to run the system, the power supply also ensures that the system does not run unless the voltages supplied are sufficient to operate the system properly. In other words, the power supply actually prevents the computer from starting up or operating until all the power supply voltages are within the proper ranges.
The power supply completes internal checks and tests before allowing the system to start. If the tests are successful, the power supply sends a special signal to the motherboard, called Power_Good. This signal must be continuously present for the system to run. Therefore, when the AC voltage dips and the power supply can't maintain outputs within regulation tolerance, the Power_Good signal is withdrawn (goes low) and forces the system to reset. The system will not restart until the Power_Good signal returns.
The Power_Good signal (sometimes called Power_OK or PWR_OK) is a +5V (nominal) active high signal (with a variation from +2.4V through +6.0V generally being considered acceptable) that is supplied to the motherboard when the power supply has passed its internal self tests and the output voltages have stabilized. This typically takes place anywhere from 100ms to 500ms (0.1–0.5 seconds) after you turn on the power supply switch. The power supply then sends the Power_Good signal to the motherboard, where the processor timer chip that controls the reset line to the processor receives it.
In the absence of Power_Good, the timer chip holds the reset line on the processor, which prevents the system from running under bad or unstable power conditions. When the timer chip receives the Power_Good signal, it releases the reset and the processor begins executing whatever code is at address FFFF:0000 (usually the ROM BIOS).
If the power supply can't maintain proper outputs (such as when a brownout occurs), the Power_Good signal is withdrawn and the processor is automatically reset. When the power output returns to its proper levels, the power supply regenerates the Power_Good signal and the system again begins operation (as if you had just powered on). By withdrawing Power_Good before the output voltages fall out of regulation, the system never sees the bad power because it is stopped quickly (reset) rather than being allowed to operate using unstable or improper power levels, which can cause memory parity errors and other problems.
In short? if the circuitry controlling POWER_GOOD is either damaged or composed of cheap components (or simply neglected, some power supplies simply tie the +5 rail to the POWER_GOOD and call it a day) then the delivered currents can easily be out of range.
The only instance a computer would not boot but allow the fans and lights to come on would be a power supply that cannot supply enough wattage to power the machine so if the computer needs 300 watts and the psu supplies only 200.
I read this as "I don't understand the concept behind the POWER_GOOD signal".
woops. I declared troll and then went so far as to respond. oh well.
