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Mains earth problem
Hallo guys!
About lost January I finished my signal generator, two boards working perfect on my table, but when I tried to put it in a chassis, I found out that when connecting the mains earth (green-yellow cable) to “zero voltage” of my power supply, LM7815 and LM7915 (IC regulators) warmed up till they died.
Another time, the “cold” of the output touched by accident to main’s earth, blowing the output transistors of the generator. Of course I have fixed, and now works perfect, but this phenomenon is very strange to me, and nothing is up in my books.
Ok, does anybody know the cause of that? Can anyone explain?
Thanks in advance!
About lost January I finished my signal generator, two boards working perfect on my table, but when I tried to put it in a chassis, I found out that when connecting the mains earth (green-yellow cable) to “zero voltage” of my power supply, LM7815 and LM7915 (IC regulators) warmed up till they died.
Another time, the “cold” of the output touched by accident to main’s earth, blowing the output transistors of the generator. Of course I have fixed, and now works perfect, but this phenomenon is very strange to me, and nothing is up in my books.
Ok, does anybody know the cause of that? Can anyone explain?
Thanks in advance!
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