polar 76 sdp wrong brake

Discussion in 'Cutters and Trimmers' started by umberto letizia, Mar 6, 2020.

  1. umberto letizia

    umberto letizia New Member

    Joined:
    Mar 2020
    Messages:
    4
    Location:
    italy
    hi

    i'm new and thanks all can help me.

    my polar 76 sdp doesn't work .the brake the parking brake is wrong by a few tenths of a millimeter .

    please let me know how i must do


    best regards, umberto
     
  2. CHOCK

    CHOCK Senior Member

    Joined:
    Dec 2016
    Messages:
    2,852
    Location:
    Managua,Nicaragua
    Hi sir:
    If you say does NOT work, what do you mean? the knife and clamp NOT coming down??
    or backauge does not work?? please explain me, more.
    Let me know.
    Blessing
     
  3. umberto letizia

    umberto letizia New Member

    Joined:
    Mar 2020
    Messages:
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    Location:
    italy
    thank you for your answer.
    when we put a measurment ,as 45.00 ,the machine hasn't able to stop to 45.00 but it stops at 44.98,then 44.99,then 45.01 etc etc
    we control the brake out the machine, it works well, but on it, lenze 14.448.08 ,there is written 24 v .instead it works only quite 30 v.
    on the board, we haven't 24 v ,or we have only for a moment,thenwe have about 15v. so the thermal stop the machine .

    we don't have diagram ,and we really don't know what to do

    best regards, umberto
     
  4. umberto letizia

    umberto letizia New Member

    Joined:
    Mar 2020
    Messages:
    4
    Location:
    italy
    hi chock

    i'm quite sure that the brake isn't the problem.
    the measurment when we start the machine is never the same: 24.73; 23,79; 24.32 etc etc : none alarm

    when we would position the back about 7 cm or less the guide touch the press without stop or alarm . there are three micro down the table: two have a led on mc schede. we don't find the led of the micro of the stop .we think it doesn't work .

    can someone help us ? thanks too much


    umberto
     
  5. NimeshSilva

    NimeshSilva Senior Member

    Joined:
    Jan 2013
    Messages:
    246
    Location:
    Sri Lanka
    Hi
    According to your description, I too feel that, before checking the brake itself, you should check the power transistor (most of the times BU426A) on the ML. sometimes, you may see that the board under it burnt or charred. Then you should definitely change it. Or else, you may try change it anyway.

    But if you got a chance to temporarily change the entire ML board, you may try it first. If that works, then you try changing the transistor.

    Cheers
     
  6. umberto letizia

    umberto letizia New Member

    Joined:
    Mar 2020
    Messages:
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    Location:
    italy
    hi cheers

    i 'm writing to thank you.as you wrote i had to change the bu426a .but i have had to change the resistance of 180r on the same ML.
    the machine works very well now.

    best regards, umberto,italy
     

  7. siraj

    siraj Member

    Joined:
    Nov 2015
    Messages:
    27
    Location:
    saudi arabia
    Hi sir, I have the problem in brake, that some technician have changed the position in brake,(loosen the three screws in the brake) so now the brake is not working problem, i mean the backgauge try to move very difficult, I checked there is correct voltage in brake and motor, only the problem is adjustment of the brake lining with the clutch, can you pls help me how to adjust the air gap correctly, Thanks in advance
     
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