Dell Optiplex 755 Won't Start
Discussion
bigandclever said:
Just to clarify, only one module?
Otherwise .. “NOTICE:If you remove your original memory modules from the computer during a memory upgrade, keep themseparate from any new modules that you may have, even if you purchased the new modules from Dell. If possible,do not pair an original memory module with a new memory module. Otherwise, your computer may not start properly”.
It has 2x 1GB Kingston in slots 1&2, with 3&4 empty as is often the case.Otherwise .. “NOTICE:If you remove your original memory modules from the computer during a memory upgrade, keep themseparate from any new modules that you may have, even if you purchased the new modules from Dell. If possible,do not pair an original memory module with a new memory module. Otherwise, your computer may not start properly”.
I swapped both Kingston for 2x 1GB Samsung from another working 755 but it still wouldn't start.
The 2x 1GB Kingstons worked fine in the 755 that I borrowed the Samsung RAM from.
eeLee said:
pull all pullable things from the motherboard - drives + power, CPU, RAM, video card. See if it does the same with nothing connected at all. Then put things in one by one starting with CPU and then RAM and video.
You will then start to understand whether the PSU is toasted or it's something else.
So far I've disconnected everything except the CPU (individually and all at the same time) and it didn't make any difference.You will then start to understand whether the PSU is toasted or it's something else.
Durzel said:
Dells can be a bit funky and esoteric, but what I tend to do in situations like this is unplug everything except the CPU and PSU, and then try booting it. You'd get a load of beeps (assuming it has a speaker, it ought to) but then you'd be further along in diagnosing the thing that's stopping it from coming on at all.
I've disconnected everything as you suggest but it only spends ~3s trying to power up before switching off again. It doesn't get to the part where it might beep.However, if I try to power it on without RAM it will beep before powering off again, so it is capable of beeping.
eeLee said:
RVB said:
I don't have a PSU without pulling a 100% working computer apart.
can you pull one close enough that you can use the power from it to core components such as mobo?However, I have now removed the power supply from the offending computer and might be able to test it in the other 755 later, since it's easier to manipulate just a power supply unit than to manipulate a power supply still fitted inside a chunky computer.
RVB said:
eeLee said:
with no CPU in mobo, it should at least error in some way, not turn off
So I guess motherboard is the forum's final answer. 
BigRuts said:
I don't intend to come across as a douche but is there some sort of sentimental attachment to this a 13/14 year old computer that is driving you to bring it back to life?
That’s exactly what I was thinking. The OP is going through a lot of hassle to get a piece of junk working again!I recently obsoleted some Optiplex 755s at work. They really are terrible by any remotely modern standards, even with Windows 10. I had to basically turn them into thin clients by the end of their tenure, as they were incapable of doing anything themselves really.
I'm invested in what's wrong with this one now though
I'm invested in what's wrong with this one now though
xeny said:
Should I have any surplus XP compatible PCs, and be headed in your general direction, would you appreciate a PM so I could drop a couple off with you?
Yes, I would appreciate a PM if at some point you happen to have some old Dell Optiplex 755 or 760, possibly 780.I don't mind travelling to collect - we all like driving on here, don't we? But if you see a V6 Insignia being driven like a granny it might be because it has a boot full of old Dells.
The model I find most useful for my XP needs is the Optiplex 755 in what is referred to as 'small form factor' (measures 34 x 31 x 9cm approx).
The 'desktop' version at 40 x 35 x 11cm is a little too large, as is the 'tower' version at 43 x 41 x 19cm.
The 'ultra small form factor' which measures 24 x 24 x 6cm approx seems to have some unknown hardware change which causes some issues with XP and older programs.
The reason I was prepared to try to get the subject of this topic working again was because it is my preferred model for the task I have in mind; Optiplex 755 in 'small form factor' 34 x 31 x 9cm.
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