Faulty Power Supply ?

V

Vikki Sixx

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Hey all,
In the last few days my computer has started humming a little (like the fan isn't turning too comfortably) and now the computer wont turn on at all.

I removed the PSU and connected that separately to a wall socket via it's kettle cord but nothing happens. The PSU has a little LED and a on switch at the back. If I flick the switch, the LED just flickers (white) very subtly. It should be Green for ON or Red for STANDBY.

Is this a faulty PSU ?
Could it be something else ?
I tried connecting a different PSU (which I thought was fine) and still nothing happens .... so may not be the PSU after all ?

Any similar experiences ?

Thanks
Victor
 
howardb

howardb

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Sounds like it's on it's way out. What model/make is it? When you removed it, did you disconnect from the motherboard - it won't power on if not connected unless you bridge certain contacts.
 
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Vikki Sixx

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howardb said:
Sounds like it's on it's way out. What model/make is it? When you removed it, did you disconnect from the motherboard - it won't power on if not connected unless you bridge certain contacts.
Click to expand...

Chinese brand .... what terminals must I bridge to check it ?
 
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Vikki Sixx

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ok, Power Supply is fine ... suppose that means the mother board is gone .... is this repairable or just get another one ?
 
Swa

Swa

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Humming sounds like a failing fan. Check if all connected fans are working. Many motherboards won't start if the cpu fan is dead.
 
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Vikki Sixx

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at first I thought it was the PSU fan that made that humming sound, but now when I tested the PSU, the fan was silent. Is there any way of testing the CPU fan without being connected to the motherboard ?
 
Swa

Swa

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Dude you should be sure the PSU is working to know if the fan is ok. The motherboard on switch is usually just a bridge to the PS-ON wire so it should work even if the board is dead. It's much safer than the manual method which you can try if the motherboard doesn't do anything. But be careful - saw a guy at a pc shop blow one up. Wanted to shout "not that wire!" but it was too late.
 
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Vikki Sixx

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I tried the "paperclip" trick to test the PSU and it is working. WOuld like to check the CPU fan now ... any ideas on how to test this ?
 
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Vikki Sixx

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Yes the PSU fan spins perfectly, and the LED at the back of the PSU is green "ON". However, when connected to the MOBO, nothing happens. Someone mentioned it could be the CPU fan that has failed. How can I test if this is the case ?
 
Swa

Swa

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Yes I mentioned the CPU fan. Sounds like the mobo is turning it off again. Try to see if the PSU fan starts turning momentarily. Must be visually because you won't be able to hear it. If necessary try to use the bridge trick while connected to the motherboard as it could also be a faulty or loose connector.
 
T

TJ99

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Vikki Sixx said:
I tried the "paperclip" trick to test the PSU and it is working. WOuld like to check the CPU fan now ... any ideas on how to test this ?
Click to expand...

Carefully stop the fan with a finget while the computer is on (only for a second or 2 though). Then let it go and see if the noise comes back.
 
Swa

Swa

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TJ99 said:
Carefully stop the fan with a finget while the computer is on (only for a second or 2 though). Then let it go and see if the noise comes back.
Click to expand...
I'm assuming that's finger. Won't work as the PSU isn't coming on.
 
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Vikki Sixx

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Swa said:
Yes I mentioned the CPU fan. Sounds like the mobo is turning it off again. Try to see if the PSU fan starts turning momentarily. Must be visually because you won't be able to hear it. If necessary try to use the bridge trick while connected to the motherboard as it could also be a faulty or loose connector.
Click to expand...

So, don't connect the wide ribbon cable from the PSU, only the 12V one ? then bridge the wide one ?
 
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Vikki Sixx

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Swa said:
Yes I mentioned the CPU fan. Sounds like the mobo is turning it off again. Try to see if the PSU fan starts turning momentarily. Must be visually because you won't be able to hear it. If necessary try to use the bridge trick while connected to the motherboard as it could also be a faulty or loose connector.
Click to expand...

So, don't connect the wide ribbon cable from the PSU, only the 12V one ? then bridge the wide one ?
 
Swa

Swa

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Vikki Sixx said:
So, don't connect the wide ribbon cable from the PSU, only the 12V one ? then bridge the wide one ?
Click to expand...
Huh? The PSU has a 24-pin connector and probably another 4-pin one near the CPU. You connect both then bridge the PS-ON wire and one of the black ones. It should be possible from the top.
 
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Vikki Sixx

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You bridge the 24-pin while connected to the MOBO ... is there no chance of damaging the MOBO then?
 
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Vikki Sixx

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Swa said:
Yes I mentioned the CPU fan. Sounds like the mobo is turning it off again. Try to see if the PSU fan starts turning momentarily. Must be visually because you won't be able to hear it. If necessary try to use the bridge trick while connected to the motherboard as it could also be a faulty or loose connector.
Click to expand...

The PSU does not even flinch ....
 
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