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Thread: Presslab, anybody... help me figure this thing out.

  1. #1
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    Post Presslab, anybody... help me figure this thing out.

    Everything I though I knew about power supplies just went right out the window...

    After getting the mod working on an old at supply, I bought a new tiny atx supply for my carpc.

    This transformer has me completely boggled.

    Starting from the outside...

    18 windings, small wire.
    4 windings, 2 small wires, starting and ending in different places
    4 windings, bigger wire doubled up
    6 windings, giant metal strip that goes directly to ground
    18 windings, thin wire again.

    HUH?

    what's the primary coil? the small 18 winds in the middle?

    should I just put the 3 sets of 3 windings, like the previous supply, and rewind everything else back the way it was? double up all the secondary windings?

    Or should I just put the thing back together the way it was, get it working on 120V, and return it for a differnt type of supply?


  2. #2
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    well, now, looking at it closely, those two 18 windings of small wire were connected together.

    there were 18 on the outside, that stopped at a point, then started again, in the same direction on the inside, making 36

    *still confused*

  3. #3
    Variable Bitrate
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    hi arby,

    my second try had the same windings on the primary side as yours, but the inner 18 where connected to the outer 17 (in my case) anyways, you can see on the pcb which is what. All the prim. windings are on one side of the transformer, and all the sec are on the other side. When rewinding I put all the prim windings (3x) on the inside and the sec on top of that.
    Both my tries gave wrong outputs (first tried ATX) I'm guessing this has to do with the difference in prim windings on the original transformer compared with the transformers you andpresslab used. With my ATX PSU presslab did some math for me which I didn't really understand, my current try is still an open post...
    If at first you don't succeed.........
    destroy all evidence you tried

    for info on t6369c LCD or Presslab's powersupply check:
    http://www.namms.tk <=updated!!

  4. #4
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  5. #5
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    Heh, I think I just figured out my problem... I posted to early. That big metal strip that had a wire going directly to ground was the 3.3V. It had six winds, but it was connected to ground right in the middle. Therefore there were 3 windings on each side of ground. The 4 windings on the next layer were the +5 and the 5 lighter duty ones further out were the +12.

    And of course the other 36 (18+18) were the primary.

    WHOO!

    alright... transformer winding time!

  6. #6
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    One last quick question...

    Why am I using 22 guage doubled up? Couldn't I just use the 18 guage wire I have? Any real differences between using two small ones and one big one?

  7. #7
    FLAC
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    Originally posted by Arby:
    <STRONG>One last quick question...

    Why am I using 22 guage doubled up? Couldn't I just use the 18 guage wire I have? Any real differences between using two small ones and one big one?</STRONG>

    The magnetic field is really powerful inside a transformer and the eddy currents cause inefficiencies. You could go with the 18 gauge instead, but your arn't doing yourself a favor.
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