lacusta

Thankyou very much audioguru for helping me. I shorted the output , the new and good 2n3055 burned instantly but it was cold! I don't know what to measure so that I could see if the current regulator works. If I will not be able to fix my actually power supply, I think I will build the power supply from bellow. 28 V, 4 A transformer is good? http://www.electronics-lab.com/forum/index.php?topic=7317.1512

My first 2n3055 has burned out. I used a new one but IT WAS BROKEN. I checked the voltage at pin 6 of U1 ad it was 11.27V (no Q4). The voltage across R5 and R6 is 5.6V. Audioguru, would you like to tell me what checks should I do to see if something else has broken?

Hello, First, sorry for my english... :-[ I am new to electronics-lab forum and a beginner. I've built this power supply and now I have a problem. When I connect Q4, the output is 17V . When Q4 isn't connected the output depends on p1 and it varies from 0V to 34.6V. With Q4 conected the voltage at pin 6 of U2 is around 0V. The voltage at pin 6 of U3 is always the same as voltage across R1 and with voltage between point 7 and point 4. I've short-circuited the output without q4 and the led not lit. Help me please! P.S. I used this circuit diagram> http://www.electronics-lab.com/projects/power/001/index.html because I 'have built it some time ago.