smps pwm ic not oscillating

Thread Starter

baiart

Joined May 21, 2011
1
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...
 
Top