Announcement

Collapse
No announcement yet.

Dell Precision 490 PSU (N750P-00)

Collapse
X
Collapse
 
  • Page of 1
  • Filter
  • Time
  • Show
Clear All
new posts
Previous template Next
    #1

    Dell Precision 490 PSU (N750P-00)

    I recently got this old computer free and i cleaned out the dust before doing anything
    it seems to have a habit of now powering on and giving a psu related error
    on the motherboard there are a few 6.3v 2200uf caps that look like they are starting to bulge near the ram
    so i opened up the psu and oh god i should have done this i the 1st place i need to take it outside and blast the bunnies out of it

    Any common fail points i should be aware of in the PSU?

    EDIT: After cleaning that out i have managed to get a code meaning "A possible system board failure has occurred."
    some times it boots other times it gives me this
    Attached Files
    Last edited by evilkitty; 04-22-2018, 08:41 AM.
    Tags: None
    #2
    Re: Dell Precision 490 PSU (N750P-00)

    This switching power supply looks like the power supply from hell
    One board on the top and one on board on the bottom
    Last edited by sam_sam_sam; 04-24-2018, 05:10 PM.
    9 PC LCD Monitor
    6 LCD Flat Screen TV
    30 Desk Top Switching Power Supply
    10 Battery Charger Switching Power Supply for Power Tool
    6 18v Lithium Battery Power Boards for Tool Battery Packs
    1 XBox 360 Switching Power Supply and M Board
    25 Servo Drives 220/460 3 Phase
    6 De-soldering Station Switching Power Supply 1 Power Supply
    1 Dell Mother Board
    15 Computer Power Supply
    1 HP Printer Supply & Control Board * lighting finished it *


    These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%

    1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
    2 Hem Saw Computer Stack Board

    All of these had CAPs POOF
    All of the mosfet that are taken out by bad caps

    Comment

      #3
      Re: Dell Precision 490 PSU (N750P-00)

      Originally posted by sam_sam_sam View Post
      This switching power supply looks like the power supply from hell
      One board on the top and one on board on the bottom
      Yeah, but its not as bad as it looks once you removed it.

      Essentially its a normal PSU with the AC-DC Part on one Board and the PFC Section on the other.

      I have two (NMB) Dual PCB PSU here myself...

      Comment

        #4
        Re: Dell Precision 490 PSU (N750P-00)

        I hope all those large heatsinks are at common ground potential.

        Comment

          #5
          Re: Dell Precision 490 PSU (N750P-00)

          My kitty likes to help me work on my power supplies too!

          Your power supply looks cool, but will be difficult to work on. If you are a "professional" electronics technician, take the pc boards out of the metal case to do repair work - leaving the interconnecting wires in tact. When doing this, you need to know where to put fingers, and where not to put fingers! If you are not tech savy, the power supply either works or should be trashed.
          Attached Files
          Old proverb say.........If you shoot at nothing, you will hit nothing (George Henry 10-14-11)

          Comment

            #6
            Re: Dell Precision 490 PSU (N750P-00)

            I would add this comment

            evilkitty—>

            If you decide to recap both board

            If I were going to do this

            I would mark the wires that go between the two boards and separate them it will be easier to deal with it that way

            But make sure that you mark each wire and take a photo of it before you start

            everell's —>

            Does your kitty get in the way when you try work on the power supply
            Last edited by sam_sam_sam; 05-03-2018, 06:59 AM.
            9 PC LCD Monitor
            6 LCD Flat Screen TV
            30 Desk Top Switching Power Supply
            10 Battery Charger Switching Power Supply for Power Tool
            6 18v Lithium Battery Power Boards for Tool Battery Packs
            1 XBox 360 Switching Power Supply and M Board
            25 Servo Drives 220/460 3 Phase
            6 De-soldering Station Switching Power Supply 1 Power Supply
            1 Dell Mother Board
            15 Computer Power Supply
            1 HP Printer Supply & Control Board * lighting finished it *


            These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%

            1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
            2 Hem Saw Computer Stack Board

            All of these had CAPs POOF
            All of the mosfet that are taken out by bad caps

            Comment

              #7
              Re: Dell Precision 490 PSU (N750P-00)

              When I recap a psu board, I do so with power OFF. So if you are going to recap your psu boards, remove the boards from the metal case (no need to remove the interconnecting wires) and change the capacitors with power OFF! Be sure you install the new capacitors with polarity correct or they will blow up. Then put the two boards back into the metal case before applying power.

              I find it to be very difficult to change capacitors on power supplies without first taking the pc board out of the metal case.
              Old proverb say.........If you shoot at nothing, you will hit nothing (George Henry 10-14-11)

              Comment

              Previous template Next
              Working...
              X