Question Asus motherboard red cpu light ( old setup) PSU??

Oct 14, 2022
hell the same setup for the past 8 years or so.
corsair 650w psu tx650w (psu that failed) corsair 520w
asus sabretooth motherboard
evga gtx 660 gpu
amd fx-6350
2- corsair 8gb ram
500gb ssd
2-hdd 7200rpm
1 dvd-rw

i went to turn it on the other day nothing happened. no light on the motherboard. ok i guess the power supply is bad. i have an older power supply that i took out of a working computer and has been sitting in dry storage. its 100 watts less but i used multiple psu calculator online and they all said this was enough for my setup. they recommended a ~450w psu. mine is rated for 480w continuously 520w max

swapped in my old psu. plug in the power flip the switch and the green led comes on the motherboard. so now i know theres power to the board. hit the switch to turn it on and nothing happens or so i thought. i tried it again and saw the red cpu led flash and the cpu fan power on for a section and turn off.

i dont have a spare motherboard or cpu or another psu. if i had to guess either my psu is old damaged or simply not powerful enough.

BUT before i go buying part after part, what are the chances when the power supply went that it couldve damaged the motherboard and/or cpu?

any suggestions? much appreciated thanks!!


In a case like this and without having other parts on hand to test with, you would basically have to find someone to pay to fix it for you, or consider a new build. IMO, would spend towards something more modern. YMMV