I have a broken Dell Precision 470 Workstation. The symptoms are as follows: Won't power up; Flashing yellow power LED on front panel; Blank STR_LED on motherboard; Yellow AUX_PWR LED on motherboa

http://www.dell.com/support/Manuals/us/en/19/Product/precision-470

Click on -
Dell Precision Workstation 470 and 670 Computer User's Guide

In the list on the right side, click on - Tools to Help Solve Problems

In the list on the left side, click on - Diagnostic Lights

Yellow (A) Green (B) Yellow (C)

"A possible VRM 1 failure has occurred"

VRM stands for Voltage Regulator Module.

It regulates Voltage for the Processor.

The Processor MUST have a steady, 'clean', supply of Voltage; and it MUST be kept within the tight voltage range, for the Processor.

Too little, or too much; and the Processor turns off. (BIOS turns it off)

Your motherboard supports two Processors.

1) Processor (CPU_0) Zero which is in the middle of the motherboard, next to the PCI Express x16 slot;

2) and Processor (CPU_1) One, which is next to it.

The VRM 1 has failed. Needs to be replaced.

http://www.ebay.com/itm/DELL-H2703-PRECISION-470-670-VRM-VOLTAGE-REGULATOR-MODULE-TH-0H2703-WS470-WS670-/380369885440

VRM's used are interchangeable.

IMHO you can remove Processor 1 (CPU_1), and it's VRM, and still use the computer; albiet slower though.

For additional questions please post in a Comment.
Regards,
joecoolvette

Dell Support > Precision 470 Workstation Desktop PC > Users Guide,

http://support.dell.com/support/edocs/systems/ws470/en/ug_en/index.htm

Tools to Help Solve Problems > Diagnostic Lights,

http://support.dell.com/support/edocs/systems/ws470/en/ug_en/advtrbl.htm#wp1057482

"A possible VRM 0 has occurred"

VRM = Voltage Regulator Module

Here is what the motherboard looks like,

http://www.ebay.com/itm/DELL-PRECISION-Workstation-470-XC838-Motherboard-with-2GB-/140795014004?pt=Motherboards&hash=item20c8096b74

[Note* Posted for photo reference only. Not for advertising.
Besides, I do not see any VRM's plugged in. Means you get the motherboard only, and no VRM's. You need a VRM ]

What the Voltage Regulator Module looks like,

http://www.thebestpartinc.com/kg229.html

(Again, not for advertising. Click on the photo of the VRM to enlarge)

Notice that your motherboard has two VRM's. This is because there are two Processors.
Apparently the VRM for one of your Xeon processors is bad. (Z-on)

Since it states VRM -> 0, it is for the Processor 0, or in the number 1 processor socket.

What does a Voltage Regulator Module do for a Processor?
Regulates voltage.

A Processor MUST have a steady, 'clean' supply of voltage, AND it must be within the voltage range for the processor.

Since the motherboard uses an Intel E7525 motherboard chipset, it can support Intel Xeon processors, with up to an 800MegaHertz Front Side Bus. (800MHz FSB)

Looking at a typical Intel Xeon single-core processor, with an 800MHz FSB, let me show you it's voltage requirements,

1.287 to 1.400 (DC)

May be just a bad VRM.

However, I would also like you to look at the Electrolytic Capacitors on the motherboard. From what I have seen, those motherboards are notorious about having capacitors go bad.

Visual identification of bad Electrolytic Capacitors,

http://www.capacitorlab.com/visible-failures/index.htm

For additional questions please post in a Comment.

Regards,
joecoolvette

It seems like the processor is overheating. Maybe you need to spread out thermal paste on the CPU.

Reseated? How Rick?

Did you;
1) Have the computer unplugged from power, and follow Anti-Static Precautions?
2) Did you clean the top of the processors, and bottom of the Heatsink's - Thoroughly, and properly apply new, fresh thermal paste?

[ If they had thermal pads on the Processors, remove them, throw them as far as you can.
One, they are JUNK. Two, you cannot reuse them.

The imprint has been made, and you cannot imprint over.

{The Heatsink, and Processor make an imprint on a thermal pad. The pad is squeezed down. You cannot re-squeeze again, and make a successful complete contact. A thermal pad also dries out a lot faster than thermal paste. Poor design ]

3) The LED lights you refer to are Diagnostic LED lights.

A, B, and C are Yellow.
The Power On LED light is Yellow,

Dell Support > Precision 470 and 670 Workstation Desktop PC Users Guide,

http://support.dell.com/support/edocs/systems/ws670/en/ug_en/index.htm

Solving Problems

http://support.dell.com/support/edocs/systems/ws670/en/ug_en/solve.htm#wp1252394

Power Problems:

If The Power Light is Amber and Green or Steady Amber;
A device might be malfunctioning or incorrectly installed.

• Remove and then reinstall the memory modules.
• Remove and then reinstall any cards.
• Remove and then reinstall the graphics card, if applicable.
  

Diagnostic Lights before P.O.S.T. (Power On Self Test)

A, B, C, are Yellow, D is blank or Off.
BIOS is not executing - Ensure that the Processor is seated correctly, and restart the computer.

http://support.dell.com/support/edocs/systems/ws670/en/ug_en/advtrbl.htm#wp1057482

Almost sounds like a problem with the motherboard voltage regulator circuit, if the Processors were handled with Anti-Static Precautions being observed, and new thermal paste being used, after proper cleaning.
{A Processor is the MOST susceptible computer hardware component to Static shock}

Motherboard Voltage Regulator Circuit
A series of Electrolytic Capacitors on the motherboard, (Yes, in a Series circuit, also), that among other duties, regulate voltage for the Processor/s.

http://www.hardwaresecrets.com/article/616

Computer unplugged from power, Anti-Static Precautions observed, remove the motherboard, and visually inspect all 'caps' on the motherboard,

http://www.capacitorlab.com/visible-failures/index.htm

Post back as to your findings, in a Comment. (Believe upper right of your page, blue Comment)

Regards,
joecoolvette

Depending on the symptoms, you may have different faults.
http://www.fixya.com/support/r4282412-find_no_post_diagnostic_information_dell
Flashing Amber power LED, normally power supply
AAGG Diag LEDs normally bad RAM
Solid Amber Power LED, bad motherboard or Expansion card connected to it.
If you need a motherboard a Precision Workstation 370 motherboard is essentially the same and is available, (8400 motherboards are scarce)
http://shop.ebay.com/i.html?_kw=T7787&_kw=DELL&_kw=Motherboard

You system heat sink is having issues. either its gone bad or it is misplaced from its position.You better consult a technician.

Browse Dell.com for the driver and follow the instructions.

Dell Precision 470 Manual can be downloaded from the following link: -
http://www.andovercg.com/datasheets/dell-precision-470-workstation.pdf

Hope you get all the information you need!
CreativeTECH

sounds like a motherboard failure.
Basic troubleshooting, disconnect all external connections except power, see if indications change, if no go remove all expansion cards see if any change, if no go disconnect all drives see if any change. If none, then motherboard.
If at any step you get a change in indications, then see if you can isolate the faulty item
DIAG LED info is here
http://www.fixya.com/support/r4282412-find_no_post_diagnostic_information_dell

please make certain your memory chips are seated into the mainboard. Also, make sure that your mainboards power cable, and your CPU's power cable (the small yellow and black one) are secured to the board. If your components are secured to the board correctly, you may have an issue with the board, CPU, or power supply. If your pc is under warranty, I suggest you contact Dell for troubleshooting.