How to tell if a TL072 is dead? How to kill it?

[varialbender]

I recently built a distortion circuit on a breadboard. I made a bunch of changes, and it stopped working correctly. It was suggested to me that the TL072 was no longer properly biased. I rebuilt it to the original design, that I knew had functioned, but it's not working. I'm wondering if it's my TL072, so... How can I test it? How could I have killed it if at all?

PS for more info on how it's not working, it sounds the same with or without 9volts. Maybe it is just a screw up, but I've gone over it a bunch of times, and it looks like it's wired up right. Very low signal, have to turn the amp way up to hear it.

Thanks again

[petemoore]

  it sounds the same with or without 9volts.
  One way is to take voltage measurements, and see if they 'jibe' with the circuit it's in.
  Another is to pop a very similar OA from a known working circuit and sub in the Qable one, voltage measurements on a known working circuit are more reliable source for chip info.
  Basically it needs to be 'setup' to test it.
  Stick another chip in that circuit and see whappens [at risk of second chip].
  How could I have killed it if at all?...Plugged it in the socket 180 degrees from pin 1 match. I'm sure there are 'less frequently observed causes.

 

[Paul Perry (Frostwave)]

the quickest & most effective way to destroy a chip, is usually to put it in backwards.
Works for me!

And the only easy way to test an IC is to plug it into a known good circuit. It is rarely worth doing this, though. And it dosn't help if you have only one chip, because you will not be able to test your test circuit then..

[SaBer]

the quickest & most effective way to destroy a chip, is usually to put it in backwards.
Works for me!

That is also a quick and effective way to burn your finger...

I was once pretty tired and forgot to put the chip in the circuit. So then I pushed in the chip the backwards, with the power on  and felt 24 volts heating my finger. After I managed to do that a second time on the same night, I decided to go to bed...

[cmat]

I have done the exact same thing burnt finger and all.  I usually put my socket with the U pointing tword the way that #1 is on the IC.  I have installed the U backwards a few times and because of that I have installed my chip backwards.  DUH!!

[johngreene]

Back in the 80's I worked on a RS232 cable modem thing and it used MC1488/MC1489 RS232 interface chips. If you happened to briefly short the negative supply pin to the adjacent pin while probing around, it would pop, make a little spark and then about 3 seconds later, the top of the IC would blow apart with quite a bang. The lab benches in the manufacturing area all had little bits of IC chips embedded in the ceiling. The techs just learned that if they were probing in that area and heard the 'pop', it was time to duck.

--john