Death of a component

[u1061810]

Hey All,
   I was just wondering what are some of the symptoms of faulty or failing ICs, transistors and caps in various distortion and modulation based effect?
Also, I think I read somewhere that caps are usually working up to their full potential just before they quit, is this true?

Thanks for any comments on these questions.

[petemoore]

I noticed when they don't work ther's something wrong with them.
 I know this sounds sarcastic, but the easiest way I've found to debug a dead chip is try another one in its' place.
 You might want to try to find what blew the first one tho before you stick another one in there.
 I don't know that you'll see the right' biasing voltages at it's pins if it's damaged tho...

[RDV]

What I hate is when you try another chip and it still don't work. That's what's happened with my Distortion +. :evil:

RDV

[u1061810]

Thanks Pete :lol: Maybe this is a poor question.


So most components don't show signs of failure before they go.

Just as a possible example ICs don't get noisy or caps don't weaken the intensity of the effect when they're dying?

[RDV]

So most components don't show signs of failure before they go.

Just as a possible example ICs don't get noisy or caps don't weaken the intensity of the effect when they're dying?

It depends. Are we speaking of a new DIY effect, or an older store-bought effect?

RDV

[u1061810]

Old store bought

[RDV]

Old store bought

Yes, in that case they can do that. Hard to test for though.

RDV

[The Tone God]

There is no general rule on part failure. Some parts fail in spectacular ways leaving obvious signs of destruction and others won't even show a mark or hint of when damaged. You can't be sure a part is ok just by looking at it. About the only thing you can say about a part's functionality vs. appearence is that you can be sure its probably not working when the part of it has a hole in it with carbon marks around it.

Test the part. You can either substitute a similar part or take readings to see if the part is working properly.

Andrew

[niftydog]

in low voltage circuits, there's rarely any indication of impending failure.  Sometime electrolytics will bulge, but usually not when hooked up to a 9V battery!

Resistors sometimes get discoloured...

Best way to check an IC is to swap it out for a known good one.  But, that could blow up your good IC as well!  If you've got a CRO you can check inputs and outputs, and if you know what to expect then you can make a judgement.