Precision T7400 and diagnostic lights 3 and 4 - General Hardware - Desktop - Dell Community

Precision T7400 and diagnostic lights 3 and 4


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Precision T7400 and diagnostic lights 3 and 4

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my workstation was working fine, but does not boot anymore.

All i get is a black screen, no bios, no post, and only the diagnostic lights 3 and 4.

I looked in the manual, but this light combination isn't mentioned anywhere.

I tried to remove and put back in everything (cpu, ram, all pover cables, vga)

but nothing changes.

Only removing the ram gives me light no 1 and some beeps (memory not recognized)

I also bought some replacement memory directly from Dell (FB-DIMMS DDR2 667 ECC), but same issue.

What shoud i do?


Any help appreciated



All Replies
  • Remove the hard drive and test the ram one stick at a time.

    You are not even getting POST.

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  • I have had the same problem, just LEDs 3 & 4 showing green. Then I replaced the RTC-Battery on the motherboard and everything worked fine again.

    Try it!