Mack: Yes i am using Proton, haven't done any change in the circuit yet but seems I might be able to run it on external oscillator by adjusting capacitors on OSC1 & OSC2 ports. Just realized that the Microchip data sheet says 15 pf on each but I have 22 pf, this maybe the problem but why doesn't it run on internal RC, this has to be figured out.