An office computer kept resetting and booting up by itself, and I, being the unceremonial office troubleshooter, was called in to fix it. Shucks, it all sounds like a bad PSU, so I yanked it off and sure enough, there were 4 bloated capacitors in that generic contraption. I replaced them all but noticed a large 5watt 10 ohm resistor at the 5 volt output rail. It's a bleeder resistor to ground. This is the first time I've seen one connected as such. It seems to me it serves no real purpose except drain half an ampere from the rail, and that's a good 2.5 watts of wasted power. I never connect any of my PSUs to the mains without being loaded and connected to a motherboard. So I'm inclined to remove it and get a cooler PSU too. On the other hand, am I missing something?
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Last edited by berniedd; 10-09-2009, 10:32 AM. -
Re: Why a bleeder resistor at the 5v rail?
Consider this. The equivalent ohms of the PC as seen by PSU on the 5V is lower than this resistor and serves to stablize the PSU if load get too low and help to keep voltage stable and assists the regulation feedback in PSU.
Leave it there.
Cheers, Wizard
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