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    #1

    help, PSU without PG SIGNAL

    i have a few fsp based power supply, 60GLN series
    the internal is identical to this thread:
    https://www.badcaps.net/forum/showthread.php?t=11662

    1. the problem is the PG signal is missing if i load the 12v rail over 20A (combined) this is not the OCP limit.
    i have active load to test it

    2. another psu have normal PG signal at first, but if i restart the psu / computer, the PG signal were lost. if i turn off (then turn ON) the psu via switch (disconnect the AC outlet) then turn on via PS-on, i have the PG signal again. but it lost again if the psu restart.

    all the voltage looks OK, even when the PG signal were lost. this make the computer refuse to boot.


    no bulging caps found, the protection circuit is PS223.
    (another psu with bulging caps already repaired)
    Tags: None
    #2
    Re: help, PSU without PG SIGNAL

    I am sure there are other users here that are more familiar with this kind of problems...

    Sometimes capacitors fail without bulging. I always check caps with my esr micro tool that tests their esr and capacity. If your psu has Capxon as the one in the photos, then there are chances some of them have dried.

    Comment

      #3
      Re: help, PSU without PG SIGNAL

      tried to change ALL of caps. but still the same.
      the caps only teapo, capxon, ost.

      still have about 10 psu with this kind of problem.

      Comment

        #4
        Re: help, PSU without PG SIGNAL

        Sounds like maybe the PSU power good circuit and/or controller may have issues... read this:

        http://en.wikipedia.org/wiki/Power_Good_Signal

        If your confident that all your voltages check out and the PSU is putting out good power, you might try and desolder the sensing wire and put it on your regular 5 volt rail to see if that has any effect.

        Comment

          #5
          Re: help, PSU without PG SIGNAL

          Originally posted by Evil Lurker View Post
          Sounds like maybe the PSU power good circuit and/or controller may have issues... read this:

          http://en.wikipedia.org/wiki/Power_Good_Signal

          If your confident that all your voltages check out and the PSU is putting out good power, you might try and desolder the sensing wire and put it on your regular 5 volt rail to see if that has any effect.
          even change the chip (ps223) does not fix the problem.

          what do you mean by put the sense wire to 5v?
          give fake PG signal from regular 5volt rail (desolder the grey cable and put it to 5v rail?)?
          already did it by connecting PG signal wire via 1N4148 to 5volt, giving PG signal delay to 0ms.
          ATX spec have delay on this signal about 100 - 500ms.
          with this 'temporary fix' the psu can turn on 90% mainboard.
          some main board cannot boot with PG signal 0ms.

          Comment

            #6
            Re: help, PSU without PG SIGNAL

            I have a Fortron FSP400-60GLC which is similiar. The PGO (Power Good Output) should go from 0 to 5 volts when power is good. Have you looked at the PGI (Power Good Input) signal on pin 1? The source of this signal is from the main +12 volt rail. This signal goes to three places:
            IS12A (current sense 12 volt line A)
            IS12B (current sense 12 volt line B)
            PGI (Power Good In)

            Between the +12 volts and PGI is a diode and resistor/capacitor network. If the diode is leaky or bad, or if one of the resistors or capacitor is bad from aging, the signal will be wrong to PGI. If the +12 is dropping due to circuit loading, or a bad filter capacitor on the +12 volt line, PGI will not be high enough and PGO will drop out. So carefully monitor the voltage on the +12 volt line and let us know what is happening there. Try using a hard disk drive or a CD ROM drive as a load and see if your PGO signal reappears.
            Old proverb say.........If you shoot at nothing, you will hit nothing (George Henry 10-14-11)

            Comment

              #7
              Re: help, PSU without PG SIGNAL

              the PGO only 25-100mv

              the diode d90 (1n4148) and r92 (100ohm or 51ohm) replaced and still have the problem.

              in the PGI signal source network, only a zener diode and a smd caps i haven't checked. i dont know the value of this parts.

              Comment

                #8
                Re: help, PSU without PG SIGNAL

                Are you testing all of these with the same mobo?
                Mann-Made Global Warming.
                - We should be more concerned about the Intellectual Climate.
                -
                Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.
                - Dr Seuss
                -
                You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
                -

                Comment

                  #9
                  Re: help, PSU without PG SIGNAL

                  @pc bonez: i'm testing with active load, monitoring all voltage output with DMM.
                  then tested the PSU with various mainboard. msi 740, intel g41, albatron nforce4, gigabyte 890FX ud7, intel S3420GPLC. the intel s3420gplc wont turn on if PG signal out of spec.

                  @everell: how much voltage at PGI if normal?

                  Comment

                    #10
                    Re: help, PSU without PG SIGNAL

                    Yes I know how it works.
                    I asked because a bad test mobo could have a shorted PG signal line.
                    .
                    Mann-Made Global Warming.
                    - We should be more concerned about the Intellectual Climate.
                    -
                    Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.
                    - Dr Seuss
                    -
                    You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
                    -

                    Comment

                      #11
                      Re: help, PSU without PG SIGNAL

                      Here are two drawings of my psu that might help you.
                      Attached Files
                      Old proverb say.........If you shoot at nothing, you will hit nothing (George Henry 10-14-11)

                      Comment

                        #12
                        Re: help, PSU without PG SIGNAL

                        I have a Cooler Master 460Watt PSU. I dont get a PG signal to boot my Desktop. Whent I Opened up the PSU, the PG circuit was outputting 0.7Volts The IC is WT7527 which gets only 0.15Volts in the PGI. WHen i checked the PIN 1 (PGI) the first Resistor was a 87K and the other side of it was getting a 15.5Volts. All other voltages 12,5,3 are fine. Please help fix this PG output problem. this is the PSU model RS460PCAR-A3.

                        Comment

                          #13
                          Re: help, PSU without PG SIGNAL

                          So the resistor is 87K Ohms as marked on the resistor? Beside the resistor, what else is connected to that PGI pin?
                          What resistance do you get between PGI pin 1 and GND pin 2?
                          Attached Files
                          Last edited by budm; 02-25-2016, 11:41 PM.
                          Never stop learning
                          Basic LCD TV and Monitor troubleshooting guides.
                          http://www.badcaps.net/forum/showthr...956#post305956

                          Voltage Regulator (LDO) testing:
                          http://www.badcaps.net/forum/showthr...999#post300999

                          Inverter testing using old CFL:
                          http://www.badcaps.net/forum/showthr...er+testing+cfl

                          Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                          http://s807.photobucket.com/user/budm/library/

                          TV Factory reset codes listing:
                          http://www.badcaps.net/forum/showthread.php?t=24809

                          Comment

                            #14
                            Re: help, PSU without PG SIGNAL

                            The Resistor is connected to a zener diode on the back side of the PCB. This resistor is too small to verify (I check this 87K using MM) it has got 5 lines brown,red,orange ,yellow,brown on it.

                            Comment

                              #15
                              Re: help, PSU without PG SIGNAL

                              http://www.realhardtechx.com/index_a.../Page24794.htm

                              This is the same board on my PSU but in a different name.

                              Comment

                                #16
                                Re: help, PSU without PG SIGNAL

                                'it has got 5 lines brown,red,orange ,yellow,brown on it.' If that is the case it will not be 87K resistor.
                                How about GOOD CLEAR pictures of both sides of YOUR board if you want the helps in troubleshooting the problems.
                                Check the resistance between PGI and GND.
                                Last edited by budm; 02-26-2016, 09:52 AM.
                                Never stop learning
                                Basic LCD TV and Monitor troubleshooting guides.
                                http://www.badcaps.net/forum/showthr...956#post305956

                                Voltage Regulator (LDO) testing:
                                http://www.badcaps.net/forum/showthr...999#post300999

                                Inverter testing using old CFL:
                                http://www.badcaps.net/forum/showthr...er+testing+cfl

                                Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                                http://s807.photobucket.com/user/budm/library/

                                TV Factory reset codes listing:
                                http://www.badcaps.net/forum/showthread.php?t=24809

                                Comment

                                  #17
                                  Re: help, PSU without PG SIGNAL

                                  The resistance between PGI and GND is 2K. I dont have access to a camera now ,so uanble to take photos now, the board is the same as the one i had mentioned earlier
                                  http://www.realhardtechx.com/index_a.../Page24794.htm.

                                  Comment

                                    #18
                                    Re: help, PSU without PG SIGNAL

                                    Basically 15.5VDC feeding the 87K and 2K Voltage divider, you are not going to get much voltage on the PGI pin.
                                    Take the resistor and the Zener Diode off the the board and check the resistance again, it can also be bad input pin PGI. I also expect a cap or two on that PGI pin also.
                                    I also do not believe the resistor is 87K Ohms, more likely 12K Ohms.
                                    That picture on the link does not do us any good.
                                    Last edited by budm; 02-26-2016, 12:08 PM.
                                    Never stop learning
                                    Basic LCD TV and Monitor troubleshooting guides.
                                    http://www.badcaps.net/forum/showthr...956#post305956

                                    Voltage Regulator (LDO) testing:
                                    http://www.badcaps.net/forum/showthr...999#post300999

                                    Inverter testing using old CFL:
                                    http://www.badcaps.net/forum/showthr...er+testing+cfl

                                    Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                                    http://s807.photobucket.com/user/budm/library/

                                    TV Factory reset codes listing:
                                    http://www.badcaps.net/forum/showthread.php?t=24809

                                    Comment

                                      #19
                                      Re: help, PSU without PG SIGNAL

                                      After removing the resistor (87K?) the connectection between the Zener and PGI is removed. There is only a resistance marked 338 which mesausres ~2.2K between PGI and GND.The zener is not shorted. The zener side of the 87K shows the 15Volts. the PGI end shows 0.15 etc. I have marked the Components.
                                      Attached Files

                                      Comment

                                        #20
                                        Re: help, PSU without PG SIGNAL

                                        anything printed on the zener?

                                        Comment

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