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eMachines T5082; Doesn't boot.. but...

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    eMachines T5082; Doesn't boot.. but...

    ...If I unlpug the ATX 12v connector going to the processor and press the power button, the system appears to somewhat boot up. In other words...


    - CPU fan never spins up
    - SYSFAN connectors also do nothing on the board
    - Keyboard LEDs light up for a second (What voltage do they use?)
    - Power supply fan kicks on
    - Can eject/close optical drive


    But if I reconnect the ATX 12v connector.. nothing happens at all. The power supply fan twitches for a split second like it's trying to start up, but ultimately gets no where. Keep in mind that the standby LED on the board remains lit regardless of the 12v connector's presence.

    As far as capacitors go, I can't really find any bad caps from just looking at them, but I'm well aware that caps can go bad without showing it too. I replaced all the 16v KZG caps next to the CPU and I'm awaiting a replacement for the taller 6.3v KZG cap under the CPU's heatsink.

    Something else to keep in mind is that the power supply I got with this eMachine ACTUALLY isn't one of those horrible Bestecs; It's a HiPro 300w PSU (Are these better?), but I also noticed that the fan in it is struggling quite a bit (Noisy, etc.). Could it have just overheated the CPU or the caps? I can't find any burn marks anywhere on the board. I've also removed the ram, disconnected all drives, but left the cpu in place. Still nothing.

    What could the 6.3v KZG cap possibly be used for? I've seen reports on the forums that these fail rather often under extreme heat. A PSU with a poor fan, a clogged up heatsink, and add together the fact that the computer was in a tight, enclosed space.. I wonder? What else could I try?

    Also, I'm a bit new to the forums.. I apologize if I posted this in the wrong area.

    #2
    Re: eMachines T5082; Doesn't boot.. but...

    get a little psu tester like the ones made by coolmax, thermaltake, etc...

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      #3
      Re: eMachines T5082; Doesn't boot.. but...

      Originally posted by shovenose View Post
      get a little psu tester like the ones made by coolmax, thermaltake, etc...
      Well, I would, but I already tested 2 other PSUs on the board and they both exhibit the same behavior on the board, minus the struggling PSU fan.

      Comment


        #4
        Re: eMachines T5082; Doesn't boot.. but...

        Sounds like a short. Should be easy to fix since shorts give themselves away and shorts that shut the supply down tend to not destroy other parts.

        PcChips M825G Socket A Motherboard Caps and MOSFET
        sig files are for morons

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          #5
          Re: eMachines T5082; Doesn't boot.. but...

          mosfet shorted in vrm

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            #6
            Re: eMachines T5082; Doesn't boot.. but...

            Looks like you guys might be right; I just installed the 6.3v replacement cap and nothing's changed.

            How does one replace a "Mosfet"?

            Comment


              #7
              Re: eMachines T5082; Doesn't boot.. but...

              could be a mosfet, also could be a mosfet driver - that isnt so easy to spot and usually just replacing them one-by-one is needed.

              Comment


                #8
                Re: eMachines T5082; Doesn't boot.. but...

                But judging from the thread severach posted, couldn't I just test them on the board first?

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                  #9
                  Re: eMachines T5082; Doesn't boot.. but...

                  Well, that's that. There was a short on the board somewhere, but I never found out where it was. I looked up some guides online on how to remove MOSFETs, but it proved to be way too much trouble for my patience and the amount of tools I have.

                  Long story short, I tried removing a mosfet for testing but ultimately destroyed it in the process along with some other circuits probably. I wasted 3 days of anger and frustration on this blasted thing. I salvaged the CPU, ram, hard drive, and DVD-RW... then I basically just threw the board shouting every swear word I know of. I think I'm going to stick with my old routine until I can take some electrical classes..

                  If a board can't be repaired with a new set of caps, I'm tossing it.

                  Comment


                    #10
                    Re: eMachines T5082; Doesn't boot.. but...

                    keep it for practice.and dont let stuff get to you.if i flew off the handle every time something challenging crossed my bench i would fix nothing!

                    Comment


                      #11
                      Re: eMachines T5082; Doesn't boot.. but...

                      Originally posted by kc8adu View Post
                      keep it for practice.and dont let stuff get to you.if i flew off the handle every time something challenging crossed my bench i would fix nothing!
                      Don't worry, I did. It's up on my shelf with some other motherboards.. I might work on it again in a few weeks or whenever I can get my hands on a better soldering kit of some sort. I think my next step is to just remove all of the larger mosfets and test again for shorts on the ATX 12v connector.

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                        #12
                        Re: eMachines T5082; Doesn't boot.. but...

                        SMD mosfets are hard to remove without hot air.
                        sig files are for morons

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