Dell Precision T5500 Desktop died - any chance of repairing?

[berntd]

Hello,
Calling all Dell and other experts

My trusty Dell T5500 Machine died yesterday while in use. It suddenly just stopped and the power went off like a power failure.

What I have done so far:
I forced the power supply to on and measured all voltages. They are all ok.
I can see the power backup LED illuminated on the motherboard.
The machine reacts to the power button and comes on for approximately 8 seconds. The fans spin for that time and the power stays on for that time.

It has 4 diagnostic LEDs (very cool!).
When turning on, these LEDs get to 1,2 flashing and 3,4 off.

From the Dell service manual I traced that the machine gets to:
State: S12
State Name: CFG
State Assignment: Resource configuration
State description: System resource configuration in progress.

I have so far tried:
Removed all RAM modules and installed them one by one into slot 1 - no change
Removed all add on cards - no change
Removed the CPU chip - no change
re-installed the CPU chip + new paste etc - no change
BIOS CMOS battery removed to allow full reset - no change

No burning smells detected (I have a good nose for that)
No bulging capacitors found.

I forced the power supply to on just after pressing the power button. The supply then stays on but the system still gets to state S12 and shuts down all the fans and all LEDs.

Could it still be power supply related, despite the voltages all being ok? I opened the supply but there was nothing burned in there.
I do not have another power supply to just try for this as it is custom Dell. I tried using an ATX power supply I have here but that immediately clicks off when attempting a power up.

Is there anything else I can try to diagnose this or is this just the end of it?

Best regards
Bernt

[PeterOz]

I would try RTC reset
Page 5 & 6 in the service manual.
This is different to the cmos battery removal
It may be wise to install a new cmos battery when you do the RTC reset.

Do you get any beep codes?

[PeterOz]

I would try RTC reset
Page 5 & 6 in the service manual.
This is different to the cmos battery removal
It may be wise to install a new cmos battery when you do the RTC reset.

Do you get any beep codes?

[berntd]

Hi PeterOz,

Thanks, I will try that.
I so not get any beep codes at all.

Also, during the short on time, I do not feel any warmth from the CPU (without any heatsink) and other chips so I think they are not even getting powered.

Best regards
Bernt

[berntd]

Hi PeterOz,

Thanks, I will try that.
I so not get any beep codes at all.

Also, during the short on time, I do not feel any warmth from the CPU (without any heatsink) and other chips so I think they are not even getting powered.

Best regards
Bernt

[phillpower2]

It has 4 diagnostic LEDs (very cool!).
When turning on, these LEDs get to 1,2 flashing and 3,4 off.

See the reply of bradthetechnut here

I forced the power supply to on and measured all voltages. They are all ok.

As a PSU puts out various voltages +3.3V, +5V and +12V it may appear that the PSU is working correctly but it is not, any significant drop of any output can prevent the system from booting up, the other scenario is a significant increase in the output which can be worse as it can fry one or more major components such as the MB, CPU, RAM, add on video card etc.

The attached videos are the ones that I use as an example to show the sort of equipment that is required to conclusively test a PSU + what can happen when testing old or cheap and nasty PSUs

What the equipment does is simulate a computer under load and so the PSU behaves as it would when it is powering your PC, multi-meters and the basic testing devices that you can purchase from some merchants only test the basic voltage output from the PSU rails and so cannot be relied on as 100% conclusive.

Cheap PSUs exploding when being properly tested

Jonny Guru video

Hi PeterOz,

Thanks, I will try that.

You revisited the forum bur left no update for Peter, where are you up to with this, do you still need help with it etc.

[phillpower2]

It has 4 diagnostic LEDs (very cool!).
When turning on, these LEDs get to 1,2 flashing and 3,4 off.

See the reply of bradthetechnut here

I forced the power supply to on and measured all voltages. They are all ok.

As a PSU puts out various voltages +3.3V, +5V and +12V it may appear that the PSU is working correctly but it is not, any significant drop of any output can prevent the system from booting up, the other scenario is a significant increase in the output which can be worse as it can fry one or more major components such as the MB, CPU, RAM, add on video card etc.

The attached videos are the ones that I use as an example to show the sort of equipment that is required to conclusively test a PSU + what can happen when testing old or cheap and nasty PSUs

What the equipment does is simulate a computer under load and so the PSU behaves as it would when it is powering your PC, multi-meters and the basic testing devices that you can purchase from some merchants only test the basic voltage output from the PSU rails and so cannot be relied on as 100% conclusive.

Cheap PSUs exploding when being properly tested

Jonny Guru video

Hi PeterOz,

Thanks, I will try that.

You revisited the forum bur left no update for Peter, where are you up to with this, do you still need help with it etc.

[phillpower2]

Abandoned thread, closed.

[phillpower2]

Abandoned thread, closed.