smps pwm ic not oscillating

Discussion in 'The Projects Forum' started by baiart, May 22, 2011.

  1. baiart

    Thread Starter New Member

    May 21, 2011
    hi everyone,
    im new in here,im seeking solution if anyone can give a piece of info to solve my obstacle in repairing smps, i am repairing a psu of a defibrillator machine,its a medical equipment(for those who are not familiar about this equipment)the problem i suffer is i cant get oscillation from the output of the pwm ic(uc2845) even if there is 12v vcc supply in it,the strange thing is in vref pin,i get 2v volts only,i believe it should be 5v,anybody came through this problem fellows please share your knowledge, for my curiosity i replaced the switching mosfet even it it seems fine and pwm ic,output filter caps also...thanks in advance...
  2. retched

    AAC Fanatic!

    Dec 5, 2009
    Do you plan on using this on as a life-saving device or as test/training equipment?