Arduino TV-B-Gone on Atmega 168 instead of ATMega328

Other Hardware General Electronics
1

I am an old FAN of TV-B-Gone, but belonging to a city where its been a mess to source all the parts then to add to my Electronics Hobby came "Arduino Uno"

First project I made was a TV-B-Gone on Arduino Uno it worked like a charm, but due to its size, its
hard to carry around.

So I ordered a Pro Mini ATMega328 (Clone) and the guy sent me a ATMega168
168 has lesser memory but still the files available at "TV-B-Gone for the Arduino"
was uploaded fine.

Now when I connect a IR LED to PIN 3 (as described in sketch ) it remains Always ON.

the PIN 13 ob-board L.E.D. does flashes showing the codes are processed and keeps on looping

while on UNO, the code runs and sleeps after end of cycle till we trigger Pin2 again.

So is it ATMega168 the issue

or am I missing something ????