Announcement

Collapse
No announcement yet.

Anyone got a Scribd account to help with schematic ?

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    Anyone got a Scribd account to help with schematic ?

    Good day folks. Long story short: I'm trying to get a schematic for a UPS which I can only find on Scribd, so if anyone has an account and is willing to help me obtain it, can you please visit this ?

    Long story: this is the story of me trying to repair a Socomec Netys PR 3000 UPS. It runs on batteries but not on mains (so it doesn't charge them back). I noticed the charger SMPD area has a few blown resistors and a blown ceramic cap. (R70, R46 and C27). Right after replacing these, I also checked on the bottom and found R56 open - this one goes between the gate of the transistor and the switching IC U4. I replaced just the resistor and since the transistor was fine, I also assumed the IC was also fine. I tried plugging it in and after a few seconds, there was a loud bang, some sparks flew out and I was now left with a big mess on my hands: the components I had just replaced went pop again, this time also with some SMDs on the bottom AND the transistor itself......great >_>

    So what happened ? I think U4 was bad to begin with and the transistor "locked up", as the open R56 would hint....I should've replaced the IC anyway.

    I couldn't find any schematics going by the "Socomec" brand, so I looked up the board model (which I can't remember right now) and after digging through some russian sites, I ended up at that Scribd page and guess what: it's actually the same board - or at least close enough that I can follow. The sad part is that I can only see the first page - the rest are blurred in typical Scribd fashion. That's when I recalled a quirk I noticed on my phone: by navigating to the same page on my phone through Chrome, the pages are not blurred in the mobile version Sadly, every time I try to zoom in, the page freezes, so the best I could do was to quickly take some screenshots and piece them together to form a semi-complete schematic. It's missing quite a few lines here and there, so it's not perfect, but the charger portion which is on the first page is mostly clear, so I could follow along and rebuild the blown part.

    There's one thing I don't understand: on the first page, BR1 is fed both by the mains AND the inverter output (the thick black lines going to BR1 are shown going through relays RY4 and RY5 and they're thrown either straight on the mains input on the far left OR the inverter output in middle of the page, where C25 is in the middle of that H-bridge). On the first page, Q13 is the dead transistor. It's got a CHG_PWM tag on its gate, which is going to U4 on the next page. The VCC pin of U4 has a 12v tag down the line. That tag comes from the third page from TX3 via D28 on the far right if I'm not mistaken. In turn, TX3 is run by Q43, which in turn is controlled by U6, which in turn gets +12v....from where ? If 12v is generated by U6 itself, how can it possibly sustain itself ? I see another transistor up top (Q42) which switches the BAT.V line to that same VCC pin, but isn't this over the rating of the IC to begin with? There's 6 batteries in series in this thing ! Interestingly, the UC3845 datasheet doesn't list a maximum input on the VCC pin, so maybe it's started by the battery voltage indeed. Even so, I see Q42 is switched by optocoupler U5 which comes on with mains present (I/P-L and I/P-N tags on the far left), so what happens when mains is NOT present ??? I see another tag ON_SW on the left via diode D31, but that leads to the last page which is a mess: too many lines close together so the screenshot turned out very poorly, so I can't tell where it's coming from

    It would be nice to get the whole thing though, that's why I'm asking for help. Cheers guys.
    Attached Files
    Wattevah...

    #2
    Re: Anyone got a Scribd account to help with schematic ?

    From what I can see, your analysis is spot on. The UC3845 starts up when the Vcc pin has 8.4V or more and this pin have a internal zener of about 36V, so it will start via D24, Q42 and R124 (autostart), o will run via ON_SW via R283 and a switch between pins 11 & 12 of CN7 (I assume in a front panel, this is not in the pdf)

    Don't have an scribd account but found a online downloader, so I attached the schematic.

    Hope this helps.
    Attached Files

    Comment


      #3
      Re: Anyone got a Scribd account to help with schematic ?

      Woohoo ! Just what the doctor ordered ! Thank man - sure beats having to mess around with Paint to stitch sh!t together ! BIG CHEERS ! We have a bunch of these UPS so this schematic is definitely going into my collection
      Wattevah...

      Comment


        #4
        Re: Anyone got a Scribd account to help with schematic ?

        Ok, I replaced all of the components with "fresh" ones and tried to power it up. I connected the battery pack and used a 60w lightbulb in series with the mains plug.

        I plugged the mains in, with the whole UPS still off, the filament glowed orange very faintly, indicating there WAS some current going into the unit, and I attempted to power it on. I held the power button, it started beeping and came on, I heard some relays clicking, nothing blew up this time, but it was obvious it was still running on battery at this point, because the battery voltage was slowly going down and the bulb went off entirely, so I don't think we've got any charging action going on (U4 is not doing its job)...it was late, so I didn't take any other measurements, but I think something related to U4 is still not working....
        Wattevah...

        Comment


          #5
          Re: Anyone got a Scribd account to help with schematic ?

          I dug deeper today and found something which may lead me closer to victory: Q28 (on page 2) gives me the same low reading across all of its 3 terminals. I believe what's happening because of this is pin 1 (COMP) of U4 (right above the transistor) is being held low to GND all the time, so U4 never actually comes on to pulse Q13....here's hoping the thing doesn't go up in flames when I replace Q28 and try again
          Wattevah...

          Comment


            #6
            Re: Anyone got a Scribd account to help with schematic ?

            Ok, I replaced the transistor today and thankfully nothing went pop, but I'm not getting an output either - the batteries still go down slowly, so something's still not right....
            Wattevah...

            Comment


              #7
              Socomec Netys PR UPS not charging

              Ok, I took some more measurements: the COMP pin (pin 1) of U4 reads only 0.4v, which I think is too low to get the IC to actually run. I followed the line and got to Q39 which is your typical 341 regulator - this is an AZ341. I measured its REF pin and I got (I THINK) 1.25v....I thought this is normal, since some of these DO have a 1.25v reference if memory serves, but if I go by what the datasheet tells me, this should be 2.5v....I'll pull it off and have a look at it anyway.
              Wattevah...

              Comment


                #8
                Re: Anyone got a Scribd account to help with schematic ?

                Ok, I managed to get it going: Q39 (AZ431) was indeed faulty - it measured the same 0.3v across its anode and cathode in both directions. I was lucky to find a matching one on a donor board and it works now
                Wattevah...

                Comment


                  #9
                  Re: Anyone got a Scribd account to help with schematic ?

                  Thank you, for the useful info.
                  I've got the same problem with Socomec NPR 2200 RT. Will be very happy if run it again. But I am not a professionalist in repairing - can replace elements and measure.
                  So. Would you help me to repaire it as give me some advices step by step.
                  In my case C27 and R46 are obviusly damaged. The UPS work normaly with charged batteries, show that charge them ( the 4 line indicator show step by step how charge it, but in fackt - do not charge them atall ).
                  Thank you in advance!
                  Last edited by SMDFlea; 06-16-2023, 02:14 PM.

                  Comment

                  Working...
                  X