Power supply blow up

[nosremark]

We have a computer that went dead yesterday, no power at all, so we replaced the power supply when the switch was turned on the lights flashed and again no power. I opened the original PS and found a burn mark on the bottom of the circuit board, opening the second PS showed a blown cap. There are no marks on the MB or anywhere else, is there anything I can check on the MB to see if it is shorting these supplies?

Thanks

 

[paparazi]

Cheaper PSU's very often damage other components when they blow, the most common being the hard drive.
Unfortunately the resultant spike completely blows the hard drive circuitry, putting it to ground, so when another new power supply is fitted this is fused straight away.

Examine the hard drive circuitry for burn marks (usually in the centre of one of the chips.

Try another new PSU but pull out the connectors to the hard drive first, if it posts you know the HDD needs replacing.

CDroms can also be shorted but hard drives are more commonly damaged

Martin

We like members to GIVE and not just TAKE.
Participate and help others.

 

[orypecos]

If you are familiar with a multimeter, you could disconnect the system from the wall, discharge all capacitors, then use the ohm meter to find out what component is grounding out. With power 'on', you could use a current tracer in some cases, but probably not in this case.

 

[edfair]

A blown cap shouldn't be the result of a short to the output. More likely a defective one that got by the QC dept.
A short should have forced the crowbar shutdown without causing any problem.

But, being cautious, follow Martin's advice on the next one.


Ed Fair
Give the wrong symptoms, get the wrong solutions.