_ab

well i looked everything you told me and it still not working....The parts you told me to look are ok!!!!i also replaced the 2N with the tip31 I didn't understand how to find the short with my ohm-meter....Could you please post a schematic with the way to do it(sorry)and also when i changed again the 3 tlo81 the same problem it was working for 30 seconds and then the voltage went for a walk......i am joking 32volt the p1 was dead and the p2 when i turned it fully clockwise the led lit... :-(

Thanks friend.... i couldn't see it :-( .So what do you suggest me to look for????? Do you think that the transistor that you told me to change makes all this problems???? Sorry if i have become bothersome

Thanks a lot for your answer!!!!!!Well tommorow i will go to buy a tip31a and i will tell you the results. When i said tlo's i meant U1, U2, U3 = TL081, operational amplifier... "The pcb in the project already has R13 connected to the positive supply" i can't see this connection in the pcb could you please show it to me????Why my fuse was blow up three timew????although i didn't have a load???? only my voltemeter in paraller.

Dear friends..... I built this power supply but i failed to make it work.....I don't know why and i hope to help me!!!!!Well the first time i gave power the output voltage was ok.and the ampere control was ok(the led was on in the fully clockwise turn).After 1 minute the voltage was 9- 22,5- 34- 0- 12,5 and so on it wasn't steady in a few words.. Today i changed the transistor q2(2n2219)i also checked for the 2n3055 but it was ok...and i added a fuse 1A after the transformer before the diodes.result????I blow 3 fuses and i think the transistor is dead too...The only modification is the diodes which the text refers to 1N5402,3,4 diode 2A and i used iN5408 but i dont think it's so important....And i also changed the tlo's...I found something but i don;t know if it is bug for sure... check the file below and see the schematic diagram.....R13 goew to C of Q2 the pcb doesn't have such a connection....But i used a bridge and also didn't work....I am desparate.... PLEASE HELP Panagiotis....