Member Avatar for Jonoman1

Hi,

I'm new to this forum so would really appreciate any help.

My Dell imension 4550 would'nt start this morning following severe thunderstorms over the weekend.

Both CD & DVD units have power lights which are permanently flashing. . The green on switch light is solid. On he back of the box there are 4 diagnostic lights which should all be solid green. 'A' is blinking amber/green and 'B' is solid amber. The other two are Ok at solid green.

I'm worried that the storms may have caused a power surge and shot the mother board.

Any help out there would be appreciated.

Thanks....

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  • Latest Post Latest Post by fainsleep

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Short, practical checklist to work through before assuming the motherboard is dead. Builds on ’s PSU/RAM suggestion and ’s pointer to Dell diagnostics, and focuses on safe, repeatable tests you can do at home.

  • Safety first: unplug the PC and ground yourself. Do not open the PSU. Work on a non‑carpeted surface and wait a minute after unplugging so caps discharge.
  • Check the power chain: try a different wall outlet and bypass any surge strip or UPS (plug the PC straight into the wall with a known good cord). The fact that the front power LED and optical drives light up means there is some power present, but that doesn’t guarantee every rail is healthy.
  • Minimal‑boot isolation: remove all nonessential devices (optical drives, hard drives, PCI cards, USB devices). Leave only PSU, motherboard, CPU, one stick of RAM and video (if needed). Try powering on. If it posts, add parts back one at a time to find the failing device.
  • Memory checks (safe, effective): test one RAM module at a time in the primary slot, then try each slot with a known‑good stick. Clean contacts gently (rub with a clean eraser or use compressed air) and reseat firmly.
  • PSU checks (don’t open it): if you have a PSU tester or a spare, swap it in. If not, shops will test rails quickly — better than guessing. Multimeter checks on peripheral connectors can confirm voltages, but only if you’re comfortable and know what you’re doing.
  • Quick visual inspection: look for bulging/leaking capacitors, scorch marks or a burnt smell on the motherboard and PSU. Any visible damage usually means the board or PSU should be replaced.
  • If the board still won’t boot: remove the hard drive and attach it to another PC (USB adapter) to recover data before replacing parts. When you contact support or a technician, report the exact LED pattern and any beep codes and list the tests you ran.

Do tests in that order. Replacing multiple parts at once wastes money. If any step is unclear or you’re not comfortable performing it, bring the unit to a local repair shop and show them this checklist.

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Member Avatar for sittas87

hi and welcome
id check the following perharps in another machine to see if its working
PSU
!RAM!

Member Avatar for Jonoman1

Thanks Sittas 87 but what exactly is the PSU and where do I find it?

Member Avatar for sittas87

Power Supply Unit(PSU) aka Power Supply.If you can get a power supply to borrow for testing you will be able to see if the problem is with the power supply or not.Also do check your RAM,theres a good chance its your RAM if it aint your PSU.
??

Member Avatar for fainsleep

Hi,

I'm new to this forum so would really appreciate any help.

My Dell imension 4550 would'nt start this morning following severe thunderstorms over the weekend.

Both CD & DVD units have power lights which are permanently flashing. . The green on switch light is solid. On he back of the box there are 4 diagnostic lights which should all be solid green. 'A' is blinking amber/green and 'B' is solid amber. The other two are Ok at solid green.

I'm worried that the storms may have caused a power surge and shot the mother board.

Any help out there would be appreciated.

Thanks....

Try this page. It has the diagnostic light and beep codes for a dell dimension 4550. I didn't see a code for a blinking A and a Yellow B, but with both being yellow/amber then it would be your memory modules as sittas87 suggested. You will need to find out the system clock or FSB of your particular computer to find out which type of ram you need if that is the problem.

DDR SDRAM (Architecture)
DDR 333 (non-ECC) only on computers with a 533-MHz system clock speed
or
DDR 266 (non-ECC) on computers with either a 400- or a 533-MHz system clock speed


This will work on either, as it is pc2100(ddr 266), but I would recommend getting this if you can, at pc2700(ddr 333) This is assuming that you want 1G of ram (2x 512) which is the max your dell can handle. You can browse the site yourself, just remember your requirements are
1) DDR SDRAM (184 pin)
2) FSB 533 -> DDR 333
FSB 400 -> DDR 266 (this one if your not sure)


Hope this is the problem, but if not take a more in-depth look at that troubleshooting guide from dell I mentioned at first.

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