PSU broke, but why


Dec 14, 2009
My old PSU broke, but I'm not sure why.
It lights the mobo but does not boot even when there is no RAM. Also the CPU fan does not run.
Replaced the PSU and all works again.

Now a worthy mention.
In my house, when the refrigerator kicks in, the light goes dim.
Does this kill PSU?

If so, what do I need to do?



Mar 15, 2007
Your old PSU may have been a poor quality brand, they tend to be more likely to fail, but even PSUs from good brands can fail.

As for the lights dimming you probably have a bad electrical system in you home that could have caused the problem, it might be worth investing in a UPS (Uninteruptable Power Suply).


apparently having imperfect/fluctuating power to the PSU slowly "erodes"the internal components. for example, when a powersucking appliance in my house turns on, the lights get dim for a second and the Mad Dog MultiMedia 350W PSU in my p4 system makes a funny clicking sound. however, its a relatively not used much psu so its not dying now(even with the c*ck-*ss fan mod) but it may be a problem in the long run!

+1. Also, you may want to hire an electrician to find out why this happens, esp. if you have an old (as in built before 1992) house.

Your source for this bit of "wisdom"?

A good PSU is designed for a relatively wide range of AC input power.

Because the only moving parts in a PSU are one or two fans, there should be nothing to make a clicking sound. If you hear a clicking sound from your PSU, it's because it is a POS.

You cannot have too much load on a breaker. If you tried, it would trip. You can, however, have inadequate wiring in the house.


May 8, 2009
A circuit that is getting up to its rated load will cause more resistance and with it heat in the wiring. If you have a typical breaker panel, most circuits are on 15-20 amp breakers. A dryer is usually on a 30 amp breaker, a electric stove a 50 amp. These are usually on a circuit of their own. A surge spike on a circuit will not always pop a breaker but can be very hard on sensitive electronics. The idea is to have a breaker kept under its rated load and sensitive electronics kept on a surge/ power conditioner. A whole house surge protection unit is very common now on new home builds. Utility power coming into your home can be very dirty thats why they sell 130 volt lightbulbs to help with small power spikes as opposed to just 120 volt ones.