Tag: 5431

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Troubleshooting a DOA

We will never accept “It doesn’t work” as a valid reason to replace a machine. The purpose of this guide is to help determine why a unit “does not work.”

Some technical knowledge is assumed with this guide.

Possible causes:

  1. Power Supply
  2. Internal Components and Cabling
  3. POST

Section 1

Power Supply

If the unit does not power on at all (no lights, no fans) when plugged in and the front power button is pushed:

  1. Make sure the power cable plugged into both the wall outlet (or UPS) and the unit securely.
  2. Make sure you push the power button on the front of the machine. You may need to open the door on the front of the machine to see the black rocker switch.
  3. If the unit still does not turn on, try a different outlet (or known working outlet on the UPS) and/or a known working power cable.
  4. If the problem persists and we get no activity within the machine (no lights, no fans), it is plausible the PSU in the unit is non-functional.
  5. Do not stop here if the machine is right out of the box! Continue with the following steps make sure it is not related to some other component!

If the unit powers on for a few seconds and then powers off when plugged in:

  1. This is a normal power-on procedure for the motherboard. In addition, you need to push the power button on the front of the machine.
  2. If the rocker/power button on the front of the machine is pushed, but the unit still does not come on, continue on with the guide.

Section 2

Internal Components and Cabling

If the unit still does not power on:

  1. Disconnect power to the machine.
  2. Start removing the top cover to the machine by unscrewing the screws on the sides and back of the case.
  3. The top cover should slide off fairly easily. There is a sticker on the underside of the top cover that has the motherboard cabling information.
  4. Locate the power supply and follow the cables to where they connect to the motherboard.
  5. Unseat and reseat the connectors to the motherboard coming from the power supply. Most connectors will have a clip to keep the plastic parts in place, but there will be a tab to pinch to unseat the connector.
  6. Pinch the tabs on the connectors to unseat them. Push the connectors back down (you will feel the tab snap into place) to reseat.
  7. From the front of the machine, follow the cables coming from the rocker/power switch to the motherboard.
  8. Make sure this cable (red/black) is plugged in to the proper pins (ON/OFF) on the motherboard (follow the diagram on the underside of the top cover).
  9. Reseat the RAM on the system.
  10. Connect power to the machine and push the power button on the front of the machine.
  11. See if any of the fans spin or any internal lights come on — specifically, the fan on top of the CPU and the green power indicator light on the motherboard.
  12. If you still do not see any indicator lights on or system fans spinning, it is most likely a non-functional power supply. 
  13. Create an RMA for the part. 
  14. If the unit begins to boot, but does not pass POST (Power On Self Test) or load the OS, continue on.
  15. If the unit powers on, passes POST and loads the OS, replace the top cover on the machine and proceed with installation.

Section 3

POST

If the unit does not pass POST:

  1. By default, beep codes are not disabled on the motherboard. So, if the unit does not pass POST, some beep code should sound indicating what the problem component is.
  2. If you cannot determine the problem from the beep code, continue.
  3. POST requires a CPU (not overheating) and video controller, and RAM must be present and accessible.
  4. Disconnect power from the system.
  5. CPU: Make sure the CPU fan is secure and has its power cable connected securely to the motherboard.
  6. RAM: Make sure RAM is seated properly and secure, and reseat if necessary.
  7. Video Controller: This is integrated into the motherboard, but if there are multiple video cards or analog boards, remove them before trying to power the unit back on.
  8. HDD: Ensure cabling (power and SATA cable) to hard drives is both present and secure, reseating/attaching if necessary.
  9. Analog Riser Card: Make sure the Molex power connector is connected to the riser card (if appicable).
  10. If all components are secure and extra components (video cards/analog boards) are removed, connect power to the machine and turn it on.

Possible outcomes:

  1. The unit powers on and passes POST: This would inidcate there is an issue with one or more of the expansion cards/analog boards. Power the unit down via the OS and try to reconnect one card at a time with a reboot to find the culprit and create an RMA for the part.
  2. The unit powers on, but does not pass POST: This would inidicate a possible motherboard issue. If you arrive at this point, and have done all the previous steps, get approval from a manager and have the unit sent in for repair.