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_ab

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Posts posted by _ab

  1. well i looked everything you told me and it still not working....The parts you told me to look are ok!!!!i also replaced the 2N with the tip31
    I didn't understand how to find the short with my ohm-meter....Could you please post a schematic with the way
    to do it(sorry)and also when i changed again the 3 tlo81 the same problem it was working for 30 seconds and
    then the voltage went for a walk......i am joking 32volt the p1 was dead and the p2 when i turned it fully
    clockwise the led lit... :-( 


  2. Thanks a lot for your answer!!!!!!Well tommorow i will go to buy a tip31a and i will tell you the results.
    When i said tlo's i meant U1, U2, U3 = TL081, operational amplifier...
    "The pcb in the project already has R13 connected to the positive supply" i can't see this connection in the
    pcb could you please show it to me????Why my fuse was blow up three timew????although i didn't have a load????
    only my voltemeter in paraller.
  3. Dear friends.....

    I built this power supply but i failed to make it work.....I don't know why and i hope to help me!!!!!Well the
    first time i gave power the output voltage was ok.and the ampere control was ok(the led was on in the fully
    clockwise turn).After 1 minute the voltage was 9- 22,5- 34- 0- 12,5 and so on it wasn't steady in a few words..
    Today i changed the transistor q2(2n2219)i also checked for the 2n3055 but it was ok...and i added a fuse 1A
    after the transformer before the diodes.result????I blow 3 fuses and i think the transistor is dead too...The
    only modification is the diodes which the text refers to 1N5402,3,4 diode 2A and i used iN5408 but i dont think
    it's so important....And i also changed the tlo's...I found something but i don;t know if it is bug for sure...
    check the file below and see the schematic diagram.....R13 goew to C of Q2 the pcb doesn't have such a
    connection....But i used a bridge and also didn't work....I am desparate....

    PLEASE HELP Panagiotis....

    post-13244-14279142536619_thumb.gif

    post-13244-14279142541002_thumb.gif

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