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Thread: presslab's powersuply..

  1. #11
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    Look very carefully for the opto's... my power supply had them HIDDEN UNDER the two smaller transformers! suprized the hell outta me

  2. #12
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    No I'm quite positive there aren't any opto's the only place they could be is on a very small bord with smd coomponents, but this is molded in plastic...
    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!!

  3. #13
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    bweh,

    as my voltages were so high +31V on the 12V lead, I thought wel let's see what'll happen if I increase the primary windings, this should bring the output voltage down right?

    not right, the voltage on the +12V lead is still about 31V. I adjusted the resistor from max to min, didn't make any difference... why didn't the voltage change when I increased the prim windings from 3 to 4?????

    please help
    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. #14
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    I haven't seen the schematics yet but, could it be a faulty voltage regulator?
    Have you rechecked your wiring?
    If it ain't broken, open it to see what makes it "tick".

  5. #15
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    Originally posted by marsjell:
    <STRONG>bweh,

    as my voltages were so high +31V on the 12V lead, I thought wel let's see what'll happen if I increase the primary windings, this should bring the output voltage down right?

    not right, the voltage on the +12V lead is still about 31V. I adjusted the resistor from max to min, didn't make any difference... why didn't the voltage change when I increased the prim windings from 3 to 4?????

    please help</STRONG>
    the feedback voltage is too low, to bring the foodback voltage up, the input to the transformer is increased, and the outputs are increased too, so the feedback is right...... thats the problem, what have you connected it to??? That makes sense doesn't it???

    [ 01-22-2002: Message edited by: SkinnyBoy ]

  6. #16
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    uhm in theorie this makes sence... not in (my) real life..
    I've connected the voltage feedback to the +5V out, but... the +5V is like 26V.

    On my previous try (ATX) I connected it to the 3.3V out this worked great. but my +12V , -12V and +5V were wrong (the -5 & 3,3 where perfect) I couldn't find the notes I made backthen so I started with an old AT supply, which doesn't have 3.3....
    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!!

  7. #17
    Variable Bitrate
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    ^BUMP^

    please help me?
    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!!

  8. #18
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    umm, the -5volts was right (I've said this before) becasue it is gotten with a -5volt regulatoron the -12volt rail, not the transformer..

  9. #19
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    I don't know why you keep bringing up the -5V but if you like it so much...

    problem I have with your previous post is that you say that the feedback voltage is too low, but this voltage is 26V I just can't imagine that this is too low?

    Arby or Presslab would you measure the feedback voltage on your design? this way I have a reference of what it should be...
    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!!

  10. #20
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    your switching circuit must not be functioning correctly..
    therefore, it cranks the voltage up, in an attempt to get the right voltage, (which seems to be 26volts... you could try disconnecting the 26volt lead from the feedback, and connect 3.3volts to it, this may give you lower voltages on the output, or even higher.. :P

    26volts??? I thought you connected the 5volt rail to the feedback, and this was 8volts??..

    [ 01-27-2002: Message edited by: SkinnyBoy ]

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