ICs not working.....

[lightningfingers]

whats a good way to tell if an ic is blown?
(other than the obvious "effect doesnt work" :wink: )

[Joep]

that's heavily depending on the type of IC you are talking about. So in the end "effect doesn't work" might be the best indication. :?

But you can for example measure (with an audio probe) if an opamp has some signal on the input and output.... etc. etc...

[SaBer]

Looking at your nick, I don't think you should touch ICs  

[petemoore]

Like those 'boxes' for electronic ignition...
 Just take it to your mechanic who has the very expensive test equipment and pay him the 60$ to diagnose your problem....this will buy a sheet of paper that tells you what's wrong.
 ...or....Buy another 'tested good' used box for about 20$, [or new for about 45$] two screws and a wire harness clip...you should have some left over for wires and spark plugs...you may never have to know what WAS wrong.
 You can measure voltages on the pins...but replacing the chip with a known good one or two is the quickest, sure fire  way I know of to determine if a chip or active component is faulty.

[niftydog]

whats a good way to tell if an ic is blown?

knowing what it does in the circuit, you use an o-scope to check if it's got an input.  If it does, check it's output.  Does it LOOK like it's doing the right thing?  It's probably fine.

But thats only good for linear ICs generally.  Also, sometimes ICs do the strangest things...

Generally I find faulty ICs by swapping them for known good ones.

[Paul Perry (Frostwave)]

There is no 'easy' way. In my experience, if one doesn't know whether or not the chip is blown, 95% of the time it isn't.
Sorry I can't help more.. but, this has worked for me. At least 19 times out of 20.

[scratch]

very 'package' dependant ... if we are talking OP-AMPs then you could stick it in a breadboard and configure it as a simple inverting amp, apply voltage to the input and check the output ... you could do similar thing with LDR or optoisolators. Logic gates become tricky depending on if you are using TTL or CMOS, and what particular 'functions' you are using. If you are talking BBD's, or other specialized chip, then that's a whole other story.

As somebody already stated, best to try with another known good chip (after re-verifying your wiring)