[RESOLVED] Dell Optiplex 755 mt desktop, won't start...windows 10
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Thread: [RESOLVED] Dell Optiplex 755 mt desktop, won't start...windows 10

  1. #1
    Join Date
    Apr 2013
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    Resolved [RESOLVED] Dell Optiplex 755 mt desktop, won't start...windows 10

    One day it was good, next day, not so much..Made no changes... When i turn it on, I get a flashing amber led, on start button, on monitor, "input not found....check video cable and video source"...
    I checked the PSU, no fans were running... I put wires on black and green, removed all connections on PSU, and the fan started, but when I put all connections back... no fan.... Is it mobo, how do I check that? This is old computer, so it may have just died?

    If anyone can make any suggestions, it sure would be helpful..... Thanks for any HELP!!

  2. #2
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    Mobo's generally don't die... But Power Supplies do.

    Wall plugs and surge protectors can cause related issues so you should try a different wall socket.

    When you press the power button - HOLD it in for a second or two longer then normal.
    If you're happy and you know it......it's your meds.

  3. #3
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  4. #4
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    Apr 2013
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    Thank you for all the sites, I am going to try several of them I got the psu out, it seems it is a mt, it had 4 screws....
    This one doesn't have bist....
    Last edited by patti686; March 14th, 2023 at 12:28 PM.

  5. #5
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    I am assuming that you do not have the full size version of the Optiplex 755, as that would have a standard size power supply with 4 screws holding it in.

    The SFF version (Small Form Factor) has instructions here:

    https://www.dell.com/support/kbdoc/e...erature-sensor

    It will also likely take a special form-factor power supply replacement.

  6. #6
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    Apr 2013
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    This is a standard size psu, it had 4 screws, I finally got it out, I didn't see the other two black screws.. The link you sent me, was a long psu, not like mine... I guess I will order another psu, don't know what else to do, I have tried everything, the battery, holding start button in... I don't have another working psu, so I guess if it don't work I can send it back.. Thanks for all your help...

  7. #7
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    Make sure that you order a decent brand of power supply, and that you check the dimensions to make sure it will fit into your Dell Optiplex 755 case. If the new power supply has about the dimensions as the old one, you should be OK. Make sure that it has the connectors you need for your motherboard and drives and other items (video card if you have one that needs a power connection, for example).

    This one should probably work for what you need:

    https://www.newegg.com/corsair-cx-se...82E16817139275

    Save all of the packaging, in case you need to send the power supply back.

  8. #8
    Join Date
    Apr 2013
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    122
    Thank you so much, I just ordered the PSU....I appreciate all your help...

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