Desktop cannot power on

[JesusLovesUs]

Just now I heard a loud pop and my house's Circuit breaker tripped.

Turns out my server desktop uplorry...

The PSU seems to be broken. Switched 2 spare PSU from other desktop to try, cannot power on. The power light will switch on and fade away after a few seconds. Fan will run.

Tried switching the rams inside to other slots, didnt work. What else should I try? I am thinking the motherboard or CPU uplorry, haven't tried swapping the CPU yet..

Any idea what's going on? What should I do?

 

[jtjt00]

Most likely your failing PSU bring motherboard along to the grave too.

 

[ZrE0_Cha0s]

Well if u can try to take out your server board and inspect is there any components like burn make or like some black spot?

 

[JesusLovesUs]

Ok, I will do that tomorrow and report back. Need to rush my assignment today D:

 

[jtjt00]

Spoiler

 

[JesusLovesUs]

I have opened up the PSU and inspected it, found no bad capacitors on it :/ The capacitors were not bloated nor was there reddish brown dried up electrolyte visible on them.
Tried a few power cables (working), but unable to jump stasrt the PSU.

Is there anything I can do to find out what is wrong with it and fix it?

 

[darkarn]

Erm you are not supposed to take apart the PSU; you could have injured yourself!

Opening up the computer case and taking a look at the internal of the computer is safe though.

Maybe can at least take pic of the mainboard and post here?

 

[JesusLovesUs]

I tried again with another PSU, everything else except the old PSU is broken. Guess I will be getting a new PSU, will see if I can locate and replace the bad capacitor on the PSU.

Thanks everyone!

 

[jtjt00]

You better give up the idea unless you are willing to risk killing your mobo and more!

 

[Koenig168]

I tried again with another PSU, everything else except the old PSU is broken. Guess I will be getting a new PSU, will see if I can locate and replace the bad capacitor on the PSU.

Thanks everyone!

I assume you know what you are doing. The capacitors can retain their charge for months and these can give you a very nasty shock.

 

[JesusLovesUs]

ah.. I didnt know they could hold the charge that long!

I will listen to your advice and buy a new one, thanks!

 

[commach]

Capacitors in computer PSU won't hold the charge for months, there are inductor and bleed resistor to discharge them. But for safety reason and you're trained in this field, advisable not to poke around in the opened chassis PSU.

DO NOT attempt to repair amplifier or similar device/equipment if you're not trained, the capacitors can indeed hold the charge for months.

 

[aismanja]

No need check psu anymore.. get a new set... but before u connect yr psu.. please check yr mobo front and back for any marks of burn...

 

[Koenig168]

Capacitors in computer PSU won't hold the charge for months, there are inductor and bleed resistor to discharge them. But for safety reason and you're trained in this field, advisable not to poke around in the opened chassis PSU.

DO NOT attempt to repair amplifier or similar device/equipment if you're not trained, the capacitors can indeed hold the charge for months.

You are assuming that the resistors are still working fine.

Generally, you are correct but if I am dealing with a possibly defective PSU, I would not take the risk.

For the OP, an article for some background info. http://www.overclock.net/a/capacitor-safety-in-power-supplies

 

[commach]

You are assuming that the resistors are still working fine.

If the bleed resistor isn't working, you can't power on the PSU let alone charging the capacitor.

Generally, you are correct but if I am dealing with a possibly defective PSU, I would not take the risk.

Nobody should take any risk dealing with capacitors. Capacitors in computer PSU is not that scary if you know the circuit and the less known function of the inductor, VR and cooling fan. The capacitors are usually drained within minute.

 

[Koenig168]

If the bleed resistor isn't working, you can't power on the PSU let alone charging the capacitor.

Thanks, didn't know that.

 

[commach]

If the bleed resistor isn't working, you can't power on the PSU let alone charging the capacitor

Thanks, didn't know that.

Likely the reason why TS's PSU cannot properly power up. The fault 99% lies with the primary circuit (AC) filter capacitor or the bleed resistor, nothing to do with the secondary circuit (DC).

 

[Koenig168]

Likely the reason why TS's PSU cannot properly power up. The fault 99% lies with the primary circuit (AC) filter capacitor or the bleed resistor, nothing to do with the secondary circuit (DC).

So if I understand you correctly, the capacity or bleed resistor is likely to be faulty. Either way, this means that there is still a risk of electric shock from the capacitor.