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Thread: Do you guys fix wall warts?

  1. #1
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    Default 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?
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  2. #2

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    Linear ones, yes. Switchers, no. Linear ones are just getting too scarce to pitch.

  3. #3

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    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.

  4. #4

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

    Code:
    +5VDC  2.0A
    +12VDC 0.25A
    -12VDC 0.25A
    
    http://www.vcfed.org/forum/showthrea...power-supplies
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  5. #5
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    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.

  6. #6
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    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
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  7. #7

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    Garland is your friend.

  8. #8
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    Quote 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
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  9. #9
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    Quote 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.

    Quote 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.

  10. #10

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

    Quote Originally Posted by Unknown_K View Post
    What does that mean?
    Garland (of Saco, ME) makes really nice rawhide hammers.

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