Dell T3600 doesn't POST, no codes, no lights, no beeps, full throttle fans only

thanks for your participation! 

yes, there are BIST button on the PSU's back, but there are no LED indicator on it. it's F635EF-00 model, didn't find any codes info for it(
what i did:
unplugged the PSU module off the Workstations at all, plugged in AC cable and pressed BIST button. result:
no LEDs light as i may see or i need to take off the cover to see them?
while i press and hold BIST button first i can hear pretty loud click once and then low noise of the fans. letting go the BIST button i can hear louder fan's noise for a second. so i suggest its OK_result if the fans may go lower speed, am i right?

connecting 24pin BUT not 8pin processor cabble to the mainboard and plugging in AC cable makes PC fans to go mad and do not stop and yellow PC_LED indication on power button is litten.
i may press power button for 6 seconds and PC will shut_down and LED is off. doing this i may pull BIST button and it will power ON PC fans for full power, releasing BIST button stops PC fans. but no LED light any more

+5VSB 9pin of 24pin connector measured 4.93v
also, PS-ON has 9.53v, isn't it too much? or, maybe powering LED start button needs more V

Hi Drtori.

Sorry, I do not know the low-level details about your power-supply unit.  I am not sure about the right voltage on the PS-ON pin; I understand this pin can be connected to any ground pin to turn the power-supply on without attaching it to a motherboard (I did it before with some cheap power-supply units to power a laser in our laboratory) so I would say its voltage is not relevant to diagnose the problem with your workstation.  It must be working right, as the power-supply turns on.

I see, the power-supply unit on your workstation looks like the ones we have in our PowerEdge servers.  It is different to the one provided with the Precision Tower 3420 I have at home.  We never had a single problem with our PowerEdge servers so I never did a diagnose on their power-supply units, but I understand the LED is behind the plastic ring where the power cable is attached using a velcro strip.  This plastic ring remains lit when the computer is running.  Don't do that for testing!

May I suggest turning off the workstation and try the self-test button while connected to the mains?

If the plastic ring is related to the BIST button on the power-supply unit, it may lit if all is ok.

Try this simple sequence:

1. turn the workstation off, and disconnect it from the mains;
2. press the power button ten seconds to discharge capacitors inside the workstation;
3. open the workstation case and disconnect the PSU from the mainboard;
4. connect the workstation to the mains;
5. without turning it on, press the BIST button to test the PSU (and only the PSU!).

If the PSU is working and the test LED is behind the ring near the BIST button it should turn on, I suppose.  Then disconnect anything from the mainboard and connect the PSU to the computer.  Beware, follow the steps (1) and (2) to avoid damaging the workstation!  My advice would be using an anti-static wrist strap if you have one available.

Try again the BIST button, this time with the power-supply connected to the mainboard and the mains, nothing else should be attached to the computer mainboard.  If it works it means the mainboard (and its processor) is ok; repeat these steps attaching a single device (both power and data) to the mainboard one at a time.  Repeat the procedure until you find the problem.

In short, if the power-supply works as I expect (I have no experience with PowerEdge-style power supply units, so I may be wrong) the plastic ring should lit when the BIST button is pressed and anything attached to the power-supply unit is working.  The workstation should be turned off all time.

I do not think it is the processor; I had been reading the T3600 manual and it clearly says that the diagnostic LED "3" should be lit when the processor needs to be re-seated, so a dead processor will probably not turn off all diagnostic LEDs, the machine should stay at LED "3."  An electric problem in other component may easily turn off all LEDs on your workstation for safety, so I think the fix may not be as expensive as you think.  It may be anything from a PCI card to the optical drive.

Good luck!

but I understand the LED is behind the plastic ring where the power cable is attached using a velcro strip.

thank you very much!!!! it really is! I took off the cover and there are a LED! and it does not works even if the PSunit is disconnected from everything! so the power supply is to blame, right !?

thank you SO much! I’m going to the repairman tomorrow, i hope he will solve the problem

I am not sure it is the power-supply unit; it is odd the diagnostic LED for the built-in self-test button is behind the workstation cover (well, it makes some sense).  If you have disconnected the power-supply unit from the mainboard and the diagnostic LED remains off when you press the self-test button (obviously with the power-supply unit connected to mains) then I would say you have a faulty power-supply unit.

The T3600 is a nice (and beautiful) workstation; hope you will be able to get the power-supply unit repaired or replaced.  These power-supply units should not be expensive, so you will be able to get one easily if the repairman is not able to get it working again.  I understand your workstation is not under warranty right now.  You can check warranty status at https://support.dell.com/, just type the Service Tag for your workstation and look into the warranty details section.

it is odd the diagnostic LED for the built-in self-test button is behind the workstation cover 

also, repairman said PS-ON voltage 9v - unacceptable and may be the cause of fault, i'm not shure he is right on it but who am i to contradict
ps. no waranty left

I cannot see the image; don't worry, it is usual.

I wish the best with the repair.  Remeber that, in worst case, you can buy a used power-supply unit cheap (~ $40 USD + shipping).

the image is about the inner undercover LED is behind the outer plastic ring, you cannot see the LED if it's not litten, all the plastic ring itself - is a LED the plastic is transparent so it conducts the light from inner to outer space, it was you who pointed me to that fact, thanks!

thanks alot for your help, as i found on youtube you may use handmade adapter to connect regular ATX psu, it's price (adapter's) is about $3-10 in local market, original dell psu is too costly for my region delivery, about $150 for used condition even

Ah, indeed.  The image can be seen now.  Yes, this one is the plastic ring I was talking about.  At least on the PowerEdges we have this plastic ring lit when the computer is turned on, and should lit for a few seconds when turned off if you press the self-test button, the computer is attached to mains and all is ok inside.

$150 USD for a used power-supply unit is too high, in my humble opinion.  I suspect some eBay sellers try to get attention to their announcements by offering low prices but charging a huge amount of money for shipping and handling.

The adapter for ATX power-supply units you are taking about seems like a good idea.  Even if you look for an original Dell PSU later, it is a cheap way to discard a failure on other components of your workstation.

PSU was fixed, PC works fine, thanks alot, friends, case closed

Glad to know your Precision Tower 3600 is working again.

Hello @Drtori , can you write here, what part or component has to be repaired in the power supply?

I have the same problem, but I do not have any schematics, so I do not know, where is the problem in the PSU 

I would suspect that you've likely moved on to something else.

But in case you're still looking for a resolution, see my post on this thread here:

Solved: Re: Precision T3610 fans on full speed, will not turn on. - Dell Community

But my power supply is perfectly fine and what steps should I take next to troubleshoot my motherboard