Hi all, I have a serious problem with the power supply. It has worked perfectly since march but now it is setting fire to the LM723's
I am on my forth now and that has just died. I have replaced all 4 transistors to see if it fixed the problem. When I switched back on the current adjust was working but it would not go over 3V before it set fire to the 723 again. I have tested the other components as best I can with my limited knowledge. The LM723's are still burning out without the supply connected to anything so it's not an external fault.
I run the circuit from a 12.5 amp 24v ac transformer through a bridge rectifier. I have got 33.5V at pin 11 and 12 and earth is ok( no shorts ) The 723's burn within a few seconds so its hard to get other voltage readings. The last one that flames shot out of melted its self to the dip socket on pins 11 and 12 but I don't know wether this was the chip internally shorting out.
Please can you give me some guidence as to how to start testing/ what voltages at pins etc.
I am really stuck with this problem and am running out of 723's!!!!
I have attached the circuit I am using it has worked fine for 8 months so I think the circuit is ok.
Please let me know what other info you need.
Thanks for your time.
Ceefna
I am on my forth now and that has just died. I have replaced all 4 transistors to see if it fixed the problem. When I switched back on the current adjust was working but it would not go over 3V before it set fire to the 723 again. I have tested the other components as best I can with my limited knowledge. The LM723's are still burning out without the supply connected to anything so it's not an external fault.
I run the circuit from a 12.5 amp 24v ac transformer through a bridge rectifier. I have got 33.5V at pin 11 and 12 and earth is ok( no shorts ) The 723's burn within a few seconds so its hard to get other voltage readings. The last one that flames shot out of melted its self to the dip socket on pins 11 and 12 but I don't know wether this was the chip internally shorting out.
Please can you give me some guidence as to how to start testing/ what voltages at pins etc.
I am really stuck with this problem and am running out of 723's!!!!
I have attached the circuit I am using it has worked fine for 8 months so I think the circuit is ok.
Please let me know what other info you need.
Thanks for your time.
Ceefna