[MoBo] High load on +5VSB power connector

Collapse
X
Collapse
 
  • Page of 1
  • Time
  • Show
Clear All
new posts
Previous template Next
  • sarouiki
    New Member
    • Oct 2008
    • 3
    #1

    [MoBo] High load on +5VSB power connector

    Hi guys,
    it's my first post on this forum! I would like to attend the discussions since I think they are very interesting!

    I got a problem with my MoBo Asus P5L-1394 (Socket775): the MoBo won't start when I press the switch-on button on the front of the PC.
    I have already made the following trouble-shooting actions:

    1. the power-on switch of the box works correctly (I also tried to switch on the PC by shorting PINs on the MoBo)
    2. I removed the MoBo from the the box and tested it on the cardholder (in order to avoid any shortening on the backside)
    3. I removed all the components leaving only CPU and RAM: nothing changed; the MoBo won't start
    4. the stand-by green LED on the MoBo works correctly when the PSU is connected and the power-cord is connected to the power-let into the wall. Something strange: the front-panel power led is light-up even if the MoBo is in stand-by (it should be off)
    5. the PSU has 2 bad caps related to +5VSB rail. I have recapped them and now the PSU works correctly on another working PC (thanks to this forum for the suggestions about recapping). I think these caps have been broken because of a too high current drain from the MoBo
    6. the +5VSB rail of the PSU provides +5V when it is not connected to the MoBo Asus P5L-1394 whilst it provides +3V when it is connected. When connected to the working PC, it provides +5V, so I think the problem could be the Asus MoBo
    7. I have connected a +5V power source from a regulated power supply (10 Amp max) between +5VSB and ground of the power connector on the MoBo in order to measure the amount of current drained by the MoBo: the result has been: about 3 Amps!!!!! I seems to be too much since no USB peripherals are powered by the MoBo!!!! I have noted that the South-Bridge IC (installed on the lower part of the MoBo) is getting very hot in few seconds so it could be the cause of the current drain. This too high current drain could be the cause of the +5VSB voltage drop and PC won't powering on!!!!

    Now the question is: what can I do? All the caps seems to be OK on the MoBo! Do u think the MoBo is garbage or I can try to do something to recover it? What can I do further?

    The PSU under test is a Thermaltake TruePower 430W!

    Thank u very much for your suggestions!
    Bests

    SaRo
    Tags: None
    • kc8adu
      Super Moderator
      • Nov 2003
      • 8832
      • U.S.A!
      #2
      Re: [MoBo] High load on +5VSB power connector

      look for a busted usb port.
      many run from +5stby to support power on by keyboard/mouse.
      they often short when broken.
      boards that get zapped through the onboard nic often overload the +5stby too.
      i have desoldered many a damaged nic chip to get these working.

        Comment

        • sarouiki
          New Member
          • Oct 2008
          • 3
          #3
          Re: [MoBo] High load on +5VSB power connector

          Hi,
          thank u very much for the answer!
          Do u think that the heating of SouthBridge could be related to a USB short or NIC short?
          How can I identify busted USB ports of NIC?
          Thanks in advance
          Bye

            Comment

            • kc8adu
              Super Moderator
              • Nov 2003
              • 8832
              • U.S.A!
              #4
              Re: [MoBo] High load on +5VSB power connector

              southbridge heating can mean its damaged.can you hold your finger on it?

                Comment

                • sarouiki
                  New Member
                  • Oct 2008
                  • 3
                  #5
                  Re: [MoBo] High load on +5VSB power connector

                  I have removed the heatsink from the SB IC in order to put the finger directly on the IC. When I connect the PSU, the SB IC becomes very very hot after some seconds. I can't keep the finger on it because it is too hot.
                  Is it a symptom of bad SB IC? I think yes but I would not!

                  Do you think that the research of the bad parts of the MoBo could be considered finished and I have to consider it as garbage?

                  Thanks

                    Comment

                    • kc8adu
                      Super Moderator
                      • Nov 2003
                      • 8832
                      • U.S.A!
                      #6
                      Re: [MoBo] High load on +5VSB power connector

                      its gone.

                        Comment

                        Previous template Next

                        Related Topics

                        Collapse
                        • cappernicus
                          Acer Spin 5 - Lenny_ICL (19771-1) -- Dead - PM_SLP_S3# held low
                          by cappernicus
                          Laptop model: Sp513-54n-74V2


                          Testing power rails (separated by chip) reveals:

                          19V_DCBATOUT - (active)

                          5V_AUX_S5 - (active)
                          5V_S5 - (active)

                          3D3V_AUX_S5 - (active)
                          3D3V_S5 27Ω - (good) - enabled by Nuvoton chip

                          1D8V_VCCIN_AUX - (good) - enabled by 1D8V_S5 PG signal -- (dependent on 3D3V_S5)

                          1D8V_S5 41Ω - (good) - enabled by 3D3V_S5 PG signal

                          1D05V_VNN_BYPASS - (good) - enabled by 1D8V_VCCIN_AUX PG signal...
                          09-25-2024, 05:19 PM
                        • AJ847.63e
                          Testing ATX PSUs under load - Does loading the ATX 24 pin also load EPS & PCIE?
                          by AJ847.63e
                          Hi Folks,

                          Just wanted to clear up a misunderstanding of mine (or what I expect is one). Isn't the 12V rail from the 24 pin, EPS and PCIE separated? IE if I put a power resistor on the ATX 12V pin that is not going to load, thus tell me if the EPS or PCIE rails are fine?

                          I was recently watching ArIs from Hardware Busters video on how to properly test ATX PSUs without using 5 figure Croma substations.

                          The PCB adapter he used breaks out the 12, 5 and 3.3V pins from the 24 pin and gives you banana plugs to connect to. That is a bit useless is it not? Aren't...
                          https://www.youtube.com
                          05-06-2025, 10:37 PM
                        • quickname
                          Cyberpower 1500AVR UPS repair
                          by quickname
                          I'd like to start out by thanking this forum for providing the info to be able to repair my 15 year old CP1500AVRLCD UPS. Here is all the info I gathered during my trouble-shooting and re-capping.

                          Like clockwork, I've had to replace the SLA batteries every 4 years. It was about that time and the UPS was acting like it needed new batteries... randomly shutting off with AC present, not being able to charge fully, and poor runtime when AC was removed. So, I replaced the batteries but noticed that it was not charging properly.

                          I decided to verify that the batteries were...
                          11-12-2023, 09:57 AM
                        • Document Archive
                          HP Elite Slice G2 + Image Load & Asset Tag Elite Slice i5-7500T Specification for Upgrade or Repair
                          by Document Archive
                          This specification for the HP Elite Slice G2 + Image Load & Asset Tag can be useful for upgrading or repairing a desktop PC that is not working. As a community we are working through our specifications to add valuable data like the Elite Slice G2 + Image Load & Asset Tag boardview and Elite Slice G2 + Image Load & Asset Tag schematic. Our users have donated over 1 million documents which are being added to the site. This page will be updated soon with additional information. Alternatively you can request additional help from our users directly on the relevant badcaps forum. Please...
                          09-12-2024, 02:20 PM
                        • Document Archive
                          HP EliteBook 1050 G1 + Image Load, Asset Tag & Testntag Notebook 1000 Specification for Upgrade or Repair
                          by Document Archive
                          This specification for the HP EliteBook 1050 G1 + Image Load, Asset Tag & Testntag Notebook can be useful for upgrading or repairing a laptop that is not working. As a community we are working through our specifications to add valuable data like the 1050 G1 + Image Load, Asset Tag & Testntag boardview and 1050 G1 + Image Load, Asset Tag & Testntag schematic. Our users have donated over 1 million documents which are being added to the site. This page will be updated soon with additional information. Alternatively you can request additional help from our users directly on the relevant...
                          09-06-2024, 10:56 AM
                        • Loading...
                        • No more items.
                        Working...