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BFG 1000 PSU BFGR1000WEXPSU Died Suddenly

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    BFG 1000 PSU BFGR1000WEXPSU Died Suddenly

    I was using this to test motherboards before putting them in a case. Worked fine, then one day I tried to power it up and nothing. I checked the fuse, it's fine. Very heavy-duty unit UCC KY and Nichicon caps, primaries are Nichicons. No signs of any damage.

    Could not locate a schematic. Label says 4 12-volt rails, each with 36A. Total 1000 watt.

    Does anyone here have experience with these and perhaps suggest where to start? I'm assuming something has gone open circuit or short somewhere. I can see many rectifiers attached to both heatsinks,

    #2
    Re: BFG 1000 PSU BFGR1000WEXPSU Died Suddenly

    Well first of all - connect a light bulb in series with the mains supply - what happens when you turn power on?

    Do you have any voltage on the Green ATX wire (PSON)?

    Measure the voltage across the big electrolytic capacitor(s) after the bridge and PFC circuit. what do you see?
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      #3
      Re: BFG 1000 PSU BFGR1000WEXPSU Died Suddenly

      Plug PSU in the wall and measure voltage 5VSB voltage - same deal as the throubleshooting I suggested for your Dynex PSU here:
      https://www.badcaps.net/forum/showthread.php?t=92116

      After this, report what voltage you have for 5VSB here. Also check voltage on PS-ON too, as dicky96 suggested above.

      Last but not least, what motherboard/system were you trying to test with this PSU when you encountered a problem with it? Reason I ask is because some very high-power PSUs need a certain minimum load to work, and preferably a 12V-heavy load. So if you tried a really low-power motherboard, that can sometimes make high-power PSUs not want to turn on. It's not too common, but I've seen it before. So some details would be nice. Pictures too, if you have them.

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        #4
        Re: BFG 1000 PSU BFGR1000WEXPSU Died Suddenly

        Pictures attached. Test data to follow








        Attached Files

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          #5
          Re: BFG 1000 PSU BFGR1000WEXPSU Died Suddenly

          Test Results:

          Purple to ground = 5V = Standby Voltage good

          Green to ground = 2V = PS-ON is BAD, should be 4 to 5 volts!!

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            #6
            Re: BFG 1000 PSU BFGR1000WEXPSU Died Suddenly

            why should green be 5v?
            it only needs to be above ground enough to satisfy the threshold of the circuit.
            what if the circuit is 3.3v?
            besides, it probably expects the motherboard to have a pullup resistor

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              #7
              Re: BFG 1000 PSU BFGR1000WEXPSU Died Suddenly

              I used the test method from Momaka in the Dynex 350 post I posted at the same time:

              Apart from that, plug PSU in the wall and check for 5V standby (5VSB). That is, check voltage between pin 9 (typically a purple wire) and any ground on the ATX connector. You should get 5V +/-5%. If that checks out and the voltage is stable, check voltage between PS-ON and ground. The PS-ON pin is typically pin #16 on a 24-pin ATX Connector and #14 on a 2-pin connector. You should get more than 3.3V here (typically between 4-5V). If not, report what voltage you get. Also, note if the fan on the PSU turns on or not when you plug it in the wall. It should stay off. Do these voltage tests with the PSU NOT connected to anything else.

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                #8
                Re: BFG 1000 PSU BFGR1000WEXPSU Died Suddenly

                yes, the PS-ON is an input, so your really just testing if it's shorted to ground.

                Comment


                  #9
                  Re: BFG 1000 PSU BFGR1000WEXPSU Died Suddenly

                  Originally posted by stj View Post
                  yes, the PS-ON is an input, so your really just testing if it's shorted to ground.
                  Well, not necessarily.

                  PS-ON is indeed an input, but it's a logic input with a weak pull-up circuit. Therefore, it's possible that the pull-up circuit (be it a resistor from 5VSB or wherever else, or an internal voltage from a supervisor IC itself) to be bad.

                  That being said, you are correct that there is no certain value for the Voltage that the PS-ON should be. From my personal experience, I've always seen it to be at least 3V. However, I just pulled a bunch of random ATX PSUs from my stash... now that we are on the topic of this ... and measure their PS-ON voltages. Most showed anywhere from 3.0 to 4.9V. But one cheape PSU surprised me - it measured 2.3V. What surprised me about it is that it's a PSU I've tested and use for powering random electronic projects, so I know it's good and turns on. It has a TL494 PWM controller with a TPS3510 supervisor IC that generates/interprets the PS-ON signal.

                  So you may be right that the 2V that bigbeark measured may not necessarily indicate a problem. It does look a bit low, though, at least from what I've seen in other PSUs.

                  That still leaves the question I asked above and didn't get an answer to: can we know what piece of hardware was attached to this PSU when it was determined that it wasn't turning On?
                  Again, the reason I ask is because some high-power PSU will NOT turn on unless they have a certain minimum load... and for a few high-power PSU's I've encountered, they needed a modern motherboard with a working CPU and RAM so that the motherboard would draw at least 30-50 Watts before the PSU would try to turn On.
                  Last edited by momaka; 01-28-2021, 11:19 PM.

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                    #10
                    Re: BFG 1000 PSU BFGR1000WEXPSU Died Suddenly

                    I was using this PSU to test all the motherboard setups I was assembling in to complete machines. I was testing AMD 939 and AM2 motherboards. I was using this PSU exclusively because I thought it would not damage any motherboard I was working on. I had finished testing an ABIT UL8 939 motherboard with a Athlon X64 3800+ X2 CPU. I had got it running beautifully with 4GB DDR Ram. I had turned off the PSU before going to bed. I should note It was all plugged into an Isolation Transformer And I have a surge protector on my home's electrical panel as I live in a semi-rural area and my furnace motherboard was wiped out in a power surge last year.

                    The next day I attempted to start the board. There was a very brief flicker from the motherboard startup LED but that was it.I tried all the same boards that had worked previously with this PSU - none
                    started. The UL8 motherboard itself is completely dead. It won't start with any of my known good PSUs. So perhaps the motherboard itself killed the PSU.

                    I had used this same PSU to test about six other AMD boards. I successfully tested Asus A8N-E, Asus M2N-E(2) and a couple of other low-power Nvidia based boards. CPU power ranged from 65w to 95w. There was a lot switching on and switching off of the PSU. I thought maybe the actual PSU switch was damaged, but power is flowing to the fuse.

                    Comment


                      #11
                      Re: BFG 1000 PSU BFGR1000WEXPSU Died Suddenly

                      Originally posted by bigbeark View Post
                      I was using this PSU to test all the motherboard setups I was assembling in to complete machines.
                      ...
                      I tried all the same boards that had worked previously with this PSU - none
                      started.
                      ...
                      I had used this same PSU to test about six other AMD boards. I successfully tested Asus A8N-E, Asus M2N-E(2) and a couple of other low-power Nvidia based boards. CPU power ranged from 65w to 95w. There was a lot switching on and switching off of the PSU.
                      Thanks for following up with the detailed info.

                      I suppose that confirms it that the PSU does indeed have an issue.

                      From your tests, it seems the 5VSB is working normally, since you do get 5V.
                      PS-ON, I'm still on the line whether or not it is good or bad, but we will see.

                      I see this PSU appears to use all good Japanese caps, so that likely isn't the issue. The PSU also looks quite packed. So at this point, I think you will just have to get your hands dirty and dig in there - that is, remove the PSU PCB from the case and attach a temporary plug to the Live and Neutral inputs to test the PSU as we go along troubleshooting. We will need access to the bottom of the PCB to take voltage measurements, so that's why you will need the PSU exposed like that. Do note that there is danger of high voltage / shock when the PSU is open like this, so you'll have to be really careful not to touch anything on the primary side when the PSU is plugged in. If you're not comfortable with this, just say so. Otherwise, please provide pictures of the bottom (solder) side of the PSU PCB - preferably high-resolution ones, so we can see/identify parts. Also, try to note all ICs you see on the primary side of the PSU and post their part numbers here (since we may not be able to see them all from the pictures.)

                      You will also need to check the voltage across the two big 450V caps on the primary at some point (note, this is the dangerous high-voltage part.) Since you're in Canada (120V AC mains), you should be getting about 160-170V DC when the PSU is plugged into the wall but not forced to turn On. When PS-ON is connected to ground and the PSU is supposed to turn on, those caps should have about 380-390V DC across them. Since your PSU is not turning on, you need to check if the voltage on those caps actually tries to go up or not as you connect PS-ON to ground. If not, then the APFC may have a problem, or the circuit responsible for sending signal to turn on the APFC (and then primary side switching devices) may be faulty.

                      It may also be helpful to test the outputs (3.3V, 5V, and 12V rails) for short circuit - measure resistance between these to ground (with the PSU unplugged, of course) and note what resistances you get here. I doubt we will find anything wrong there, since a shorted output will typically make the PSU try to turn on (fans in the PC and PSU spin for like half a second, then stop), but then stop - i.e. a short "blip" of power.

                      Originally posted by bigbeark View Post
                      The UL8 motherboard itself is completely dead. It won't start with any of my known good PSUs. So perhaps the motherboard itself killed the PSU.
                      That adds an interesting twist here.
                      Any info on what happens when you try to turn on that motherboard with another working PSU? Do the fans in the system try to spin and then stop? Or does pressing the power switch on the front panel do absolutely nothing? If it's the latter, check 5VSB when the PSU is plugged into the motherboard and the wall - you should still get 5V. If the motherboard has a problem and is shorting the 5VSB, then obviously nothing will work and the motherboard will appear completely dead.
                      Last edited by momaka; 02-04-2021, 11:46 PM.

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                        #12
                        Re: BFG 1000 PSU BFGR1000WEXPSU Died Suddenly

                        Momaka, I finally got the ABIT UL-8 to go, but the joy was shortlived. I cleaned and reset the RAM, reset the CMOS changed out the battery. The BIOS code reader was giving a different code each time1E,26,4E,02,1D,14,20 etc.

                        Finally got it to boot the OS with 1 stick RAM in the slot closest to the CPU. With only 512mb it got into the Dekstop but would not respond to my request to shut down. I could hear it paging to the RAM. Had to shut down manually.

                        I tried more ram and it booted again, but threw up Kernel messages, unable to page. with 2 sticks of Ram it was throwing memory errors although I know both sticks are good.
                        After that I tried everthing but the BIOS Code reader never saw anything but code 14, or 02, or 1E.

                        Looks like the motherboard timer is toast to me. So even though they were not powered on it looks like the motherboard perhaps failed and took the PSU with it.

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                          #13
                          Re: BFG 1000 PSU BFGR1000WEXPSU Died Suddenly

                          Originally posted by bigbeark View Post
                          Looks like the motherboard timer is toast to me. So even though they were not powered on it looks like the motherboard perhaps failed and took the PSU with it.
                          Again, not likely.
                          If the motherboard does respond to power-up commands (regardless if it POSTs or not), then it couldn't have take the PSU with it.

                          The only way a motherboard can take the PSU with it is if something on it fails short-circuit *AND* the PSU protections don't work for some reason, making a component blow in the PSU. But if that was the case, the motherboard would no longer have powered up anymore.

                          So that's not the issue, and the proper way to troubleshoot this complex of a PSU is to get part numbers of all the ICs, get their datasheets, then see which IC may be showing an erroneous signal, suggesting some part of that circuit around it may be faulty (and more often than not, it's usually not the IC's fault, so I don't suggest to go replacing ICs blindly.)

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                            #14
                            Re: BFG 1000 PSU BFGR1000WEXPSU Died Suddenly

                            Momaka, thanks for your help. As of today, I now have five or six PSUs that require attention. Two Thermaltake TR-430's, the BFG and an Ultra 350w.

                            I will get to these but will probably start with the simple ones.

                            The original intention was to get motherboards sorted into working, salvageable and junk.
                            I'm thinking for that purpose I need a completely trustable power supply, probably a new good quality one for testing mainboards.

                            I had no idea how Power Supplies could become so flakey with age.

                            Thanks for the safety reminder. I have often replaced bad caps in simple PSU's.
                            While attempting to diagnose one Antec with the cover off, I discovered the large heatsink was live! So somehow a MOSFET was electrically grounding to the heatsink I guess.

                            Comment


                              #15
                              Re: BFG 1000 PSU BFGR1000WEXPSU Died Suddenly

                              Originally posted by bigbeark View Post
                              Momaka, thanks for your help. As of today, I now have five or six PSUs that require attention. Two Thermaltake TR-430's, the BFG and an Ultra 350w.

                              I will get to these but will probably start with the simple ones.
                              Sounds like a good plan.

                              This one (the 1000W BFG) is indeed one of the more complex ones, so probably best to leave for last - even though it is probably one of the nicer PSUs.

                              The ThermalTake TR-430's should be very easy to work on and probably a good starting point. All they really need is just new caps on the output (and a few of the small caps). Otherwise, they are very simple and very reliable units. I have both a TR-430 and a HEC Orion HP585d, which are essentially the same thing. My TR-430 is close to 14 years old and I use it almost exclusively for testing. I have abused it quite a bit with faulty graphics cards, and never managed to kill it. With good caps, they are nearly bullet-proof due to their simple design (yet, not so simple that they lack protections like some of the cheaper PSUs.)

                              Originally posted by bigbeark View Post
                              The original intention was to get motherboards sorted into working, salvageable and junk.
                              I'm thinking for that purpose I need a completely trustable power supply, probably a new good quality one for testing mainboards.
                              No need for a good PSU.
                              Just get a bunch of good quality Japanese capacitors. (Digikey, Mouser, badcaps.net... or wherever - though probably not Amazon. Ebay - maybe.) And recap the two TR-430's. Like I said, they are rather easy to work on in terms of soldering and parts are not hidden or hard to get to.

                              Originally posted by bigbeark View Post
                              I had no idea how Power Supplies could become so flakey with age.
                              Bad caps, typically. That's actually just about the only thing that can go wrong with them with age.

                              Originally posted by bigbeark View Post
                              While attempting to diagnose one Antec with the cover off, I discovered the large heatsink was live! So somehow a MOSFET was electrically grounding to the heatsink I guess.
                              The primary heatsink is live on A LOT of PSUs. I've seen it not live on very few. So always just assume it's live and don't touch it. This goes for any power supply, not just ATX ones.

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