a few tips:1) power it up for the first time through a 100ohm resistor, and measure the voltage over that resistor: this assures you if there is short.2) you need to make sure that the dc working points are correct. Measure voltage on Q1's b / c, Q2's b/e/c, Q3's b/e. and compare them to what you expect. For example, Q1's b should be about 0.7v, Q2's b should float with RV2, etc.3) if you have a scope, it would be helpful but get the dc working points and report back.
1) no idea what "led" you are talking about.2) the voltage I was talking about was the respective points vs. ground.
You need to raise RV2's wiper so that Q2's vbe goes towards 0.6-0.7v and Q3's base goes above 0.7v.