7010, dead PSU?

Buy a new power supply.. Be aware that power surges usually damage more that just the psu. Consider replacing the computer before spending too much on replacement parts. 

 JNPVV OptiPlex 7010 SFF Power Supply AC240AS

Schematics and Pinouts are never provided.

You can be killed by the voltage inside a power supply.  :Surprise:

thanks but another psu costs as much as another tower whereas a capacitor or component costs only a few pence. I know its the psu because I swapped it with a working one and now the tower works fine. I would like to repair the psu.

The issue is that when you disconnect all cables the high voltage Filter capacitors inside can hold enough of a charge to stop your heart in the same way that a defibrillator does.  This is not a joke. More than one thousand people are killed each year in the U.S. due to electric current, and several thousand more are injured.  Current flowing inside the body can cause deep burns and cardiac arrest. 

https://www.youtube.com/watch?v=4F2J1Dkf4Is

thanks for the huge red warning. I pull the mains plug out before I dismantle any power supply. No really.

please understand, I'm not a child. I don't need huge loud warnings about fixing a psu. I've repaired many a device in the past and done plenty of soldering. Would you please now stop with the wailing and warnings of impending death. Enough already. I just want some advice about which component is most likely to be the problem.

Due to safety concerns, Dell does not repair PSU (power supply unit) or have PSU disassembly documentation. Our policy has always been to exchange them while inside the purchased three year warranty period.

There is no advice forthcoming due to the liability aspect.  Power Supplies are not user serviceable.  This is also why schematics and pinouts are also not forthcoming.  They are never published.

https://www.utica.edu/faculty_staff/qma/powersupply.pdf

i have found this video, even though it is not the same psu, but you can get started with it: https://www.youtube.com/watch?v=Tlq2-W1Xq8s

I feel you bro...      

Anyway,  before doing anything.....   Unplug the device from the mains then after opening the power supply you have to

1. discharge the big capacitors which stores most of the charge. You need to have a set of gloves or screw driver with insulation and just short the terminal of the huge cap..  oftentimes it creates a spark, so at least you have an idea... this is the most important of all i think...

Electricity can kill that is why most of the comments above are scary...  But when you know what you are doing then it is not scary at all.  

Remember Knowledge is Power.

2. After the most important step above you need to start checking with the fuse.. it can be tricky some fuses used in dell power supplies are  sometimes of different type... 

I found in some dell desktop they are using tube ceramic type..  also in some Small form factors they are using

the TR5 subminiature time lag fuse https://www.ebay.com/itm/T2-5A-2-5-Amp-250V-TR5-Time-Lag-Subminiature-Fuse-x10/152295385485?hash=item237583298d:g:y~oAAOSwa-dWlem-

3.  look for bulging caps if any... sometimes even caps that look good are already dried up and need to be replaced.  

4. Also check for the bridge rectifier, normally this is one of the main culprit aside from the caps...  normally it is attached to heatsink for dell powersupplies but for others could be just ordinary 4 diodes in bridge.

5. Check other  components such as mosfet regulators.

ALWAYS REMEMBER every time you plug in the mains for testing, you need to discharge it to avoid electrocution...  Trust me i have been electrocuted several times with this kind of repairs so be careful.  Treat it differently with other electrical device repair...  You must be very careful in power supply repair because of the great risk.

Hope this helps.