There are many possibilities, for a start you may always have made a mistake during construction?.
But this error usually means the PIC isn't getting switched to programming mode (13V on MCLR), the most common cause is too little voltage from the PSU, or too much ripple on it. Try feeding 18V from two 9V batteries in series to the power input of the board.
iv made some replacements....like "b80c800 to w02m bridge rectifier" and "c3=220uf/40v to 220uf/50v" are those replacements okay,sir? BTW im feeding a 12v to my board using an cpu power supply...plz help sir....
iv made some replacements....like "b80c800 to w02m bridge rectifier" and "c3=220uf/40v to 220uf/50v" are those replacements okay,sir? BTW im feeding a 12v to my board using an cpu power supply...plz help sir....
Those replacements are fine - BUT, using a 12V supply isn't anywhere near enough, the circuit says 16V - 30V DC, when it says 16V minimum it means it! - it can't possibly work off 12V DC.