Dell Optiplex 3060 Micro USFF (IPCFL-CG Motherboard) - No LED / Short Circuit

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  • thinkcentre
    USFF enthusiast
    • Nov 2025
    • 4
    • Germany

    #1

    Dell Optiplex 3060 Micro USFF (IPCFL-CG Motherboard) - No LED / Short Circuit

    Hello,

    this is my first post at Badcaps and in general i am new to fixing electronics. I am looking forward to learn a bit more about diagnosing and repairing :-)

    What I have around is a DELL OPTIPLEX 3060 Micro (USFF), which is not powering on, even not showing any signs of life (No amber / white LED).
    I got a original 65W DELL PSU / Power brick (PA-12 / 074VT4) which hopefull should be the correct one. I could get another DELL PSU with the Partnumber 0G6J41 with the same 4.9mm DC Jack connector as the one I already have, but I dont think that would help (maybe I am wrong, but I don't think its the PSU for now).

    When I plug the PSU into the wall socket, the white LED on the DC-plug lights up, but as soon as I plug it into the DELL PC, the light turns off and stays like that until I re-plug the PSU to the wall socket.
    Also while plugged into the machine (after the led on the cable turned off) the voltage drops on the DC jack.
    From what I read online so far, this problem is common on some 3060 Micro's and it's because of the short circuit protection of the PSU.
    This information, with some other information online regarding this behavior leads me to the conclusion that the motherboard itself has a short circuit.

    I received the machine in this non-working state and would like to get it back up running.

    For my tools, I have a soldering iron and a digital multimeter, microscope, IPA and other basic utilities. I also already downloaded the board view and board diagrams from the other thread here on badcaps, but i am not very experienced in reading them correctly yet.

    The DC-Jack itself on the motherboard looks good to me, there is no physical damage.
    I already measured some of the components, e.g. the coils (mentioned in another thread) which all seemed to have resistance to ground on one pin.

    Also, on the DC-Jack I measured with the diode-test / continuity function of my multimeter:

    outer pin (ground, black) <-> inner pin (vcc, red) .556V
    outer pin (ground, black) <-> center pin (data pin, blue) 1.473V
    inner pin (vcc, red) <-> (data pin, blue) open line

    And for resistancy I measured (multimeter in 2M Ohm mode):

    outer pin (ground, black) <-> inner pin (vcc, red) .273 M Ohm
    outer pin (ground, black) <-> center pin (data pin) .114 M Ohm
    inner pin (vcc, red) <-> (data pin, blue) .388 M Ohm

    Click image for larger version

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    Click image for larger version

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    How do I proceed? What should I measure next?

    Thank you very much and kind regards
  • thinkcentre
    USFF enthusiast
    • Nov 2025
    • 4
    • Germany

    #2
    I have a update,

    when checking the bottom of the board i noticed the following:

    Click image for larger version

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    DC-Jack is for orientation. In the green box there is a AS393M-G1 voltage comparator.
    Here is the datasheet: https://www.alldatasheet.com/datashe...AS393M-G1.html

    According to the datasheet, the most left bottom pin/leg is for GND, where the most right top pin/leg is for VCC. When measuring against GND (from metal cover of the usb port for example) i get continuity on both of them. But i think it only should be on the GND pin of course.
    I also think that maybe this IC itself isn't damaged, rather some components supplying the VCC for it, am i right with this thought? also, the ic is relatively far away from the dc-jack.

    Thank you for everyone helping

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