Packard Bell desktop will not power up

pigeonpants

I would welcome any suggestions to try to resolve I have replaced the power unit but no improvement. The PC does not power up at all, no fans no lights would really appreciate any sensible suggestions all I have is to pick it up and throw it out of the window.

thanks

colin79666

Kettle lead? Can usually be swapped with the monitor lead to test.

pigeonpants

thanks
i have previously swapped the power lead and power is getting to the PC (briefly the front light flashes)

caveat_emptor

Pressing the power on switch signals to PSU power up the mobo.
It could be the power switch is faulty. To check this trace the powerswitch wiring to the mobo and remove the connector and short the two pins with a screwdriver. If the PC doesn't power up then it suggests a mobo/processor fault.

pigeonpants

Caveat
excuse me labouring the point / short the two pins on the mobo? or removed lead

thanks

caveat_emptor

Shorting the two pins on the mobo makes the circuit that should power up the mobo.

macman

You say you replaced the 'power unit', by this do you mean the PSU (inside the case)? Did you confirm if the original PSU was dead, or did you just change it anyway?

pigeonpants

Caveat
no power to mobo when shorting so does that indicate mobo fault?

thanks for your help

pigeonpants

macman
i presumed wrongly that the (internal psu) power unit was faulty

thanks

macman

But did you test the old PSU to see if it was faulty? The reason I ask is that sometimes when the PSU goes it takes out other components, including the motherboard. So replacing a blown PSU wil not get it to boot.
If the original PSU was OK, then the fault lies elsewhere. Power switch is the first thing to eliminate after the PSU.

pigeonpants

Macman
no i didnt test it just went on a hunch
how can i test the old one now it is removed?
Caveat suggested a test above to test the switch which i have tried
would welcome any further advice/suggestions