Resolved Dell Studio 540 350watt psu required

Hello,
I have checked the front switch wiring and its all ok, it has never been touched or disconnected. This issue started when the pc wouldn't start after a shutdown. There just seems to be no power.
I have had the old psu tested at a local pc repair shop and he showed me on the tester that it is ok. Now that we know its not the power supply, can you advise anything else that could cause the pc not to start up.
Regards

 

It is not the wiring "to" the switch or the switch itself I was commenting on. They should be fine unless physically abused. It is where the two wires "from" the front panel switch connect to the motherboard's front panel I/O header that needed to be checked to ensure they were re-connected to the correct two pins. For all the front panel button does is put a short between (connect) those two pins when the button is pressed.

For solder on a circuit board to melt, there would have to be some extreme heat - not likely to happen in a real world scenario under normal operation. It would have to be caused by some other component shorting out creating "excessive" current. And that would likely trigger the PSU to shutdown. I am not saying it can not happen, but I am saying you would likely be able to see some heat related damage, perhaps even smell it.

Sadly, since the PSU seems to work, I am suspecting the CPU. You can pull all but one stick of RAM and test with one at a time, but again, I fear the CPU. And the only way to test that is to try the CPU on another system, or a known good CPU on this system. The problem there is the risk of damaging the second CPU. This is something better left to a shop where they often have spare parts for testing laying around.

 

Dell Studio 540 350 watt required

Hello Guys, thanks for all your info. I finally got it sorted. I took my psu to a local shop who advised me (following plugging it into a little tester and all light flashing) that it appeared to be ok. I tried the new psu I bought and still couldn't get it to work. I took the whole pc, with my old psu in it back the the shop and on testing they found the psu was not working. They fitted the new psu and it worked. So once again hanks for the help and advice.
Best Regards.

 

Great! I am glad you got it sorted out. This must have been one of those cases where not having a proper load with the plug in tester provided inaccurate results. So when the tester put a tiny 10W load on the PSU, it tested fine. When presented with the realistic load of the motherboard, RAM, CPU, drives, and graphics solution, the PSU choked. As I noted above, these testers are not conclusive.

I am curious as to why? Do you think the power on wires might not have been connected to the motherboard correctly?