Please friends there is some problem with my atmel uc89C51

[lalitch91]

My project is Countdown timer

**broken link removed**

And whyen i put the programmed uc frsh in IC holder it works poperly but when i remove and put it again it doesnt work.. This happened with 3 uc in same manner.

Please also look at the crystal oscillator connected at 18 nd 19 pin.. there is no capacitor in this circuit .. Is this the problem?? Plz reply me as soon as possible i need this badly..

 

[Sceadwian]

Crystal oscillators require load capacitance to operate properly, instability (sometimes working sometimes not) if WHY they're needed. You knew enough to point out hte lack of load capacitors, why did you not include them?