hanging problem with pic 16f876a

[BYY]

hi...
i have made voltage stabilizer and circuit is successfully tested on vero board many times... but when i try the same circuit on pcb it started giving abnormal behavior... sometimes it works fine and sometime not ok.. even if i plucked pic off and then again put it on socket it stops working accordingly... can sumbody help me out.. thanks

 

[Tahmid]

Could be because you might have a problem in the PCB. Did you check the PCB correctly? It could also be due to noise and EMI from surrounding components. Did you filter the power lines? Do you have bypass capacitors on the PIC power lines?

 

[BYY]

yes i have check it. pcb is ok because some tym it works perfectly... yes i hav used .o1 decoupling capacitor and reverse biased diode on pow supply of pic.. now m not getting where the problem is..