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TL074 CN test

Coconuttopdrop

Sep 7, 2012
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Sep 7, 2012
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Hi.

I'm repairing a AMEK mixing board but i dont have an extensor to power the channel's that i'm fixing.
What i'm doing is comparing some readings on a good channel with the bad channel.

The EQ section of the board as 4 TL074CN IC's, and some are busted, but i dont have a way to see wich are ok and wich are busted because i cant power the circuit.

So i need to do some kind of circuit to test the IC's.
The TL074 brochure has a audio amp circuit (fig.25) wich i can try to replicate, but i have some questions.

Using a DC power supply, should i feed 12V to CC+ and hook up the ground to CC- and feed 6V to ground?

Thnks
 

Harald Kapp

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Nov 17, 2011
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That is not the way to connect the supply to the OpAmp.
For Vcc+ = 12 V use Vcc-=-12 V and GND=0V. You need a dual supply or 2 supplies. Or you build a virtual ground. Both techniques are discussed here.

To give the issue another spin: Why build a (comparatively) complex test setup which still will not tell you whether the OpAmp will work correctly in the original circuit? The TL074 is rather inexpensive. I'd just replace all the OpAmps by new ones.
 
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