The danger of PSU fan replacements.

[tp4tissue]

Fan dies, you go to dat amazon, buy new one fan. OK but which one.

On budget PSUs, @ 80% efficiency,  It will have to dissipate anywhere from 10-20 watts @ its lowest duty state.   

THAT is extremely dangerous if someone replaces an original PSU fan with one that requires a higher starting voltage. Which means the fan will not start spinning to cool that first 100watts worth of power draw. This is actually an enormous amount of heat.

If you put your hands on 5-20watt passive heatsink, it's burning to the touch. The ICs go to 80-100C. 

Budget PSUs use cheaper and fewer ICs for voltage regulation. Each IC gets hotter, and sustain higher duty. NOT cooling the first 100watt cycle will significantly heat up the PSU, reducing its lifespan dramatically, as 95% of a PSU's life is spent in that lowest duty bracket.

This is less of an issue on High end PSUs, because they get bigger heatsinks, better ICs, and are "nowadays" designed for Zero-RPM.   ALTHOUGH, even here, zero-rpm is generally bad for Vrms, which is why the high end models usually have a switch to turn off zero-rpm.


IN THE END, you don't care if the Power supply breaks,  you care about it not taking out the rest of the system during the explosion.

So, before you buy a super high end fan and think this will work great, you must test the duty cycle.

[Leslieann]

Don't open PSUs unless you know what you're doing.

The capacitors in there are strong enough to kill you and it will hurt the entire time.

[LASERman Projects]

The capacitors in there are strong enough to kill you and it will hurt the entire time.

This is untrue and unnecessary scaremongering - thrust me I have experience with charged capacitors.
BTW most PC PSUs will deplete all caps pretty quickly after unplug.

The danger is only when you plug-in exposed PSU and forget about it putting your fingers inside.

[tp4tissue]

Don't open PSUs unless you know what you're doing.

The capacitors in there are strong enough to kill you and it will hurt the entire time.

It's not a myth, they CAN kill you, but you have to be touching them in a very specific way where the current crosses from one arm to the other across your heart. 

Or if you have a pace maker.