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LM317 adjustable voltage reg problem.

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Fixed resistor and or pot burnout LM317T reg

Greetings
I have read all your posts on this subject but none has solved my issue.
I have three working power supplies all wired the same way using the 317T I eventually added the 2n3055 bypass to increase the output on the other three.
But on needing a fourth all of a sudden I have this burnout problem any suggestions?
It even burns up the 317T went through a half dozen so far. Using the same make model transformer as used in previous working one.
 
Greetings
I have read all your posts on this subject but none has solved my issue.
I have three working power supplies all wired the same way using the 317T I eventually added the 2n3055 bypass to increase the output on the other three.
But on needing a fourth all of a sudden I have this burnout problem any suggestions?
It even burns up the 317T went through a half dozen so far. Using the same make model transformer as used in previous working one.
You forgot to post your schematic of the LM317 with a 2N3055 booster transistor.

The 2N3055 is NPN. Maybe it is connected as an emitter-follower at the output so the voltage regulation is poor.
You are supposed to use a PNP power transistor connected at the input so it is part of the voltage regulator circuit.

Please post your schematic.
 
I am not using the 2n3055 on this supply I only mentioned it on the other ones for general knowledge.
This is the first stage to building a dual supply but the variable regulator stage has to work first this is the first step.
I did not post a schematic because basically there all the same I have tried various configurations all seem to work as long as the 317 is hooked up correctly but now after several working supplies I am getting this over heating and burn out problem. I purchased twenty LM317T reg online and some pots that might suggest defective parts but they are working fine in at least one of my supplies. I am totally confused as to why.
 
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Burnout problems

I am not using the 2n3055 on this supply I only mentioned it on the other ones for general knowledge.
This is the first stage to building a dual supply but the variable regulator stage has to work first this is the first step.
I did not post a schematic because basically there all the same I have tried various configurations all seem to work as long as the 317 is hooked up correctly but now after several working supplies I am getting this over heating and burn out problem. I purchased twenty LM317T reg online and some pots that might suggest defective parts but they are working fine in at least one of my supplies. I am totally confused as to why.
 
A genuine American LM317 is blowout proof. If it gets too hot then it simply shuts down until it cools then it starts working again. But if you have a heatsink too small so it heats and cools over and over then the thermal stress might damage it.

Purchased online? E-Bay?? Maybe you got cheap Chinese fakes.
 
I Here Ya

Your probably right all the way.
I almost never ask for help been in electronic and computers all my life. I build projects every day nothing better to do with my time I am retired now.
Which is partially what prompted me to buy in quantity instead of quality.
Thanks so very much for listening will be making that American part run within the hour (Smiles).
 
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