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Help with a Battery charger.

Discussion in 'Repairing Electronics' started by thudpucker, Dec 7, 2008.

  1. thudpucker

    thudpucker New Member

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    Aside from all the suggestioins like 'just get another one!' and 'Call Schumberger'
    I already did that, nothing's avaliable for this model any longer. I wanted to understand this battery charger. I may have a use for the 'intelligent' part of the Charger.

    The Charger is just plumb dead. No hum from the transformer. I have not taken the meter to it yet. It's cold in my Barn. Too cold for monkeying around where my hands are shaking.

    Two top photos are the Charger itself, and the heat sink inside the back of the Charger that two Diodes (I think) set into. I think you can see the sockets which are a Spring loaded tab, holding the diode to the heat sink.

    Then the two photos of the Diodes that came out of the Holders in the Heat sink. I dont know if they are Diodes. I havent looked at them with a meter yet.

    [​IMG] [​IMG]

    [​IMG] [​IMG]

    The Diode sitting on the transformer kinda looks like there might have been some flames coming away from the connection. It's a red colored ash I think.

    Have any of you worked with this kind of an intelligent Charger? And if you did, have you replaced the 'intelligent' (voltage sensing part) with another circuit from the archives of millions of inventors?
     
    Last edited: Dec 7, 2008
  2. user_88

    user_88 Member

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    I have a similar charger ....10A ....different brand .....
    Mine has some sort of thermal disconnect feature ... that is, if it gets too hot due to current overload, the charging stops until it cools down .....
    It still works after 30 yrs or so ....have not opened it up....

    Just wondered if this might be what's wrong with yours ....I would guess the thermal cut-out is some sort of bi-metallic strip ...that opens when it heats up ....probably has some sort of contact point ....need to examine for conductivity if that's the case ...Also ....just check all connections for clean, solid metal to metal contact ....diodes included....You can probably check the transformer for continuity on primary and secondary ....

    Where is the needle on your ammeter? .......
     
    Last edited: Dec 7, 2008
  3. thudpucker

    thudpucker New Member

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    "Where is the needle on my Ampmeter?"

    Its still in there [;)]...Seriously, It never moved. I plugged it in, didnt hear the Hum and the clamps dont spark, the Ampmeter needle dont move a bit.
    This thing is old. It was used when I got it. I'm going to assume there is an open in the AC input, or the primary. That may be where the Thermal protection located.

    I'm not able to bring it in the house (shmbo) would have me sprawled out in the yard along with the wreckage of the dead charger, and its too cold in the barn right now.

    88, dont pull that cabinet off. It's bad luck I think. If it aint broke, dont fix it, you know that one.
    Thanks for the hint.
     
  4. dave

    Dave New Member

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  5. RODALCO

    RODALCO Well-Known Member

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    charger

    Most likely that your charger has been connected to an accu reversely and the ammeter needle flown of the schale and the diodes popped hence the burn marks on them.
    All is not lost here yet.
    Use an ohm meter and check primary and secondary winding of the transformer for continuity.
    As your charger has two diodes , the secondary winding has probably 3 wires so called centre tap TX driving two power diodes.
    You can try to source 2 times 10 Amp diodes, but easier and cheaper is to get two 25 Amp bridge rectifiers and use only one diode of each rectifier.
     
  6. thudpucker

    thudpucker New Member

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    OK, Rod, Thanks for the hints. Our winter rollercoaster is keeping me out of the barn right now, but I'm saving all this for the big event when the weather breaks.
    While I'm checking the Transformer I'll check the meter for DRT (Dead right there)

    I'd never seen diodes like that. I'll shop for the 25a Bridge Rectifiers in the meanwhile.
     
  7. micronetric

    micronetric New Member

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    Looks more like the rest of the power cord. Inside part which broke away.
    A hot connection caused the power cord to fry inside the rubber grommet.
     
  8. JKF1000

    JKF1000 New Member

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    They are definatly diodes you have there, they are quite common if you know where to look, I have a one or two in my spares collection, usually very reliable, make sure the contact areas are clean, it looks as if you have had a little bit of burning going on, but I dont think they will be permanantly damaged, once you have checked your AC refit the diodes and I'm guessing they will be OK.
     
  9. Leftyretro

    Leftyretro New Member

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    There are restoration projects and there are basket cases. I wouldn't put a dime or an hour of labor into trying to resurrect that thing. Maybe strip the transformer out and see if it can be sandblasted and checked out and if still good, save it for another project some day. ;)

    Lefty
     
  10. thudpucker

    thudpucker New Member

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    Lefty you probably have a higher degree of maturity than I do.
    When it gets warmer, I'll get into that thing. Then I'll know if you are more right than I am!
    At this point I have three Chargers. Two are dead. One of the dead ones was a basket case too. I re-freshed all the Slip-on connections and got almost six more years out of it.
    With a track record like that how can I miss? I'll give my Basket case just one more try.

    I have a couple ideas for inventions. What or Where would I post them on this site?
     
  11. Leftyretro

    Leftyretro New Member

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    I meant no disparity to your efforts. I spent about 8 years searching out charity and thrift stores for vintage 70s hi-fi equipment to restore and keep or resell on E-bay. They made fine equipment in those days and most were worth the effort to try and restore as I would usually find them for around 10% or their resell value. The trick was to try and stick with units that were in decent cosmetic condition as the internal electronics were very repairable in most cases. However if it had scratches, dents, rust, etc then I learned to just leave them alone or just buy them to for parts value.

    My philosophy was as the singer said, know when to hold them, know when to fold them. ;)

    I realize in your case there is no resell factor, you just have hungry batteries that need feeding. ;)

    Good luck with your project and keep warm.

    Lefty
     
  12. shokjok

    shokjok Member

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    The transformer failure is assumed to be overload or weak wiring. The diode pictured showed evidence of a spark, as for the transformer it is best to replace it. Somewhere in that charger a thermal fuse should be added to prevent this re-occurence.
     
  13. tonigau

    tonigau Member

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    For ctr tap 2 diode rectifier...
    Even cheaper still to use 1 Bridge rectifier, connect as normal just don't use -Vout tab. Only the 2 top diodes (to +Vout) are in use.
    Although there would be less thermal resistance using 2 bridge rectifiers.

    NB. Each diode in a bridge rectifier is rated at 50% of the total A rating for mains frequency rectification bcos its only conducting each half phase.
     

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