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Do you guys fix wall warts?

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    Do you guys fix wall warts?

    My Belkin soho KVM went on the fritz tonight, I checked the power adapter and it was putting out 12VDC but the unit was just barely lit making noise. Easiest thing was to replace the power supply and the KVM came back to life. The power supply, in question was an ebay purchase OEM for the KVM and I had a couple spares. Just for the heck of it I took the supply apart, it had 1 screw to open it and the board slid out showing nothing blown but a domed 470uf 25V capacitor. Generally I toss these when they go bad but I ordered a few capacitors just to see if that was the only issue. Do you guys bother fixing these things?
    What I collect: 68K/Early PPC Mac, DOS/Win 3.1 era machines, Amiga/ST, C64/128
    Nubus/ISA/VLB/MCA/EISA cards of all types
    Boxed apps and games for the above systems
    Analog video capture cards/software and complete systems

    #2
    Linear ones, yes. Switchers, no. Linear ones are just getting too scarce to pitch.
    Be polite and I may let you live.

    https://www.youtube.com/playlist?lis...5NBVfKX5471R9U

    Comment


      #3
      Yes if i can get them apart without doing too much damage, Usually i find it's just a new Cap or 2 that's required.

      Comment


        #4
        I've got some NOS units with the following outputs:

        Code:
        [COLOR=#333333]+5VDC  2.0A[/COLOR]
        [COLOR=#333333]+12VDC 0.25A[/COLOR]
        [COLOR=#333333]-12VDC 0.25A
        [/COLOR]
        http://www.vcfed.org/forum/showthrea...power-supplies
        PM me if you're looking for 3" or 5" floppy disks. EMail For everything else, Take Another Step

        Comment


          #5
          Depends. If it's an AC wall wart, no--not worth the trouble as there's likely a problem in the transformer. If it's an uncommon output (say +20VDC) or a linear one with a combination output (+5 +/-12) or one with a high-current output, I'll consider it. Otherwise, no. I've got too many wall warts that probably should have been discarded long ago.

          Most wall warts are easy enough to disassemble--even the ones without screwed-together halves. Just a tappy-tap-tap around the seam with a rawhide hammer is often enough to get things to separate. A little acrylic cement gets things back together again.
          Reach me: vcfblackhole _at_ protonmail dot com.

          Comment


            #6
            Don't think I own a rawhide hammer, just a rubber mallet. If I have to go to the effort of busting a PS open I lose interest unless it is something super rare.

            The AC wall wart advice makes sense.

            As far as this one goes if the cap replacement doesn't fix it it goes in the trash, they were not expensive enough to put that much time into them.
            What I collect: 68K/Early PPC Mac, DOS/Win 3.1 era machines, Amiga/ST, C64/128
            Nubus/ISA/VLB/MCA/EISA cards of all types
            Boxed apps and games for the above systems
            Analog video capture cards/software and complete systems

            Comment


              #7
              Garland is your friend.
              Be polite and I may let you live.

              https://www.youtube.com/playlist?lis...5NBVfKX5471R9U

              Comment


                #8
                Originally posted by KC9UDX View Post
                Garland is your friend.
                What does that mean?
                What I collect: 68K/Early PPC Mac, DOS/Win 3.1 era machines, Amiga/ST, C64/128
                Nubus/ISA/VLB/MCA/EISA cards of all types
                Boxed apps and games for the above systems
                Analog video capture cards/software and complete systems

                Comment


                  #9
                  Originally posted by Unknown_K View Post
                  Do you guys bother fixing these things?
                  It really depends on the design of the wall wart if it's worth it to repair or not. Some OEMs use really badly designed switching circuits (netgear comes to mind) that fail because components are heavily abused, not just because they use garbage capacitors. If the unit is also ultrasonically welded together, it's not worth it unless you have a way to fuse the case halves back together. You definitely don't want to risk the thing breaking apart on a customer and have that legal nightmare to deal with. If the wall wart is held together with screws or clips and it uses a good switching topology, I'll consider fixing it.

                  I can get good quality 12V 2A switching wall warts from the parts house I have an account with and get basically any voltage I need by putting a buck or boost converter in line with it.

                  Originally posted by KC9UDX View Post
                  Linear ones, yes. Switchers, no. Linear ones are just getting too scarce to pitch.
                  Unless you plan on stripping the core and rewinding it, linear ones almost always get pitched. Linear wall warts have bad problems with voltage drift due to the tight windings coupled with heat and vibration damaging the lacquer/varnish insulation, causing them to short together. This process happens even if you don't use the transformer, as the internal coil pressure alone will cause damage to itself.

                  I've had linear wall warts which were just a year or two old already be far out of voltage spec. The single bobbin types which are the most common that use stacked windings are the worst, but dual bobbin types suffer it too.

                  Comment


                    #10
                    I've got hundreds of linear ones, and over the years I've only had two get out-of spec so far.

                    Originally posted by Unknown_K View Post
                    What does that mean?
                    Garland (of Saco, ME) makes really nice rawhide hammers.
                    Be polite and I may let you live.

                    https://www.youtube.com/playlist?lis...5NBVfKX5471R9U

                    Comment


                      #11
                      Originally posted by KC9UDX View Post
                      I've got hundreds of linear ones, and over the years I've only had two get out-of spec so far..
                      Every linear wall wart I have (at least a dozen) is out of spec to the point they're unusable, I just keep them around to smash open for the copper. My buddy also has two large boxes full of them which after something blew up he plugged into one, he went and tested all of them and found that all of them were either on the knife edge of being out of spec or being far out of spec.

                      Comment


                        #12
                        Originally posted by GiGaBiTe View Post
                        Every linear wall wart I have (at least a dozen) is out of spec to the point they're unusable, I just keep them around to smash open for the copper. My buddy also has two large boxes full of them which after something blew up he plugged into one, he went and tested all of them and found that all of them were either on the knife edge of being out of spec or being far out of spec.
                        The linears are usually badly regulated and rely on a load to keep them in spec. They will always fail with no load. Try with a resistor that is about half load...
                        Dave
                        G4UGM

                        Looking for Analog Computers, Drum Plotters, and Graphics Terminals.

                        Comment


                          #13
                          In my experience, AC wall warts fail very rarely; it's mostly a matter of them being overloaded and then failing thermally.
                          Reach me: vcfblackhole _at_ protonmail dot com.

                          Comment


                            #14
                            Originally posted by g4ugm View Post
                            The linears are usually badly regulated and rely on a load to keep them in spec. They will always fail with no load. Try with a resistor that is about half load...
                            Many of these WERE tested with a load and were still very much out of spec.

                            Comment


                              #15
                              I had a need for a small SATA hard drive power supply for a test. I looked in my hellbox and turned up a wart for a Compaq 14" LCD display (very early; the backlights eventually went dim and it wasn't worth repairing).

                              But the 'wart (takes an IEC power cord) has nameplate ratings of +5VDC @ 2A and +12VDC @ 2.3A with a nice long power lead ending in a spring-loaded 6-pin mini DIN plug. I repurposed the plug (it was nice one) onto one of my IR Keyboard-to-PS/2 adapters and fitted a standard 4-pin Molex to the end. A quick check with the thing running a 500GB SATA drive shows the voltages to be bang on.

                              The moral is not to be too cavalier in tossing 'warts; some have their uses.
                              Reach me: vcfblackhole _at_ protonmail dot com.

                              Comment

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