How can you find out whether an IC is dead or not?

[Elledan]

I've got the feeling that I've found the culprit in this circuit I'm working on: a dead IC.

How can I verify whether it's really dead? I can't replace it since I've not a similar IC available.

 

[mrCide]

multimeter? Or some ish.

 

[Elledan]

Yeah, I've got a multimeter, but I've no experience with verifying IC's. Which methods can you use to do so?

 

[chainbolt]

Excuse the stupid question, what is an "IC"?

 

[Elledan]

IC = Integrated Circuit

 

[Murphyrulez]

If you have the schematic for the circuit, and you can see what voltages are supposed to be coming from what legs of the IC, turn the circuit on, and use your multimeter to measure the voltage on each leg. See what is not there. Be careful not to short across two legs of the IC with your probe.

Paul

 

[Elledan]

Unfortunately, I do not have the schematic of this circuit.

It's the circuit inside a MS Intellimouse. The IC (SPMC01A-198, made by MS) is the only part which can be malfunctioning, since the rest works without problems.

Thanks anyway

 

[frizzlefry]

Hmmm, what's the codes on the IC? I love debugging! MAybe I can helpOk Found this so far

 

[frizzlefry]

What project is this for anyways?

And did you jsut tear this chip out of the mouse?

 

[Killbat]

Enjoy this datasheet

How exactly did you conclude that this chip is to blame?

 

[Elledan]

<< How exactly did you conclude that this chip is to blame? >>


I first checked for any visual damage, which wasn't there. Then I checked all other parts (except the IC). The LED's and those 'things' on the other side could of course be damaged as well, but then I would have got different results when I connected the mouse to the PC. It now just freezes right after boot-up. That's why it's most likely the IC that is causing those problems.

Thanks for the datasheet

 

[Elledan]

<< What project is this for anyways? >>


It's another futile project to quench my curiosity to the inner working of things

[/i] >>

And did you jsut tear this chip out of the mouse?[/i] >>


No, the whole circuit is still in one piece

 

[Harvey]

Without a schematic, you're pretty much out of luck. You have to know how it works and what is supposed to happen before you can analyze whether it is working. Basically, unless it is smoking when you power the system up, the way to test it is to look at each pin for the expected signal or state when it is in use.

Can you read a part number? If so, you can go to the manufacturer's site and look at application info to see if you can psyche out how it is being used in your circuit.

If it is socketed, replacing it would tell you if it's bad, or it may blow another good IC, depending on what caused the problem. If it is a complex part (CPU, controller, etc.) that is hard soldered to a board, and you don't have a lot of experience replacing them, I'm afraid you'll have to write it off or get some help. Since it's a mouse chip, I'm guessing that's what it is.

Beyond the science project value of trying to fix it, mice are so cheap that it isn't worth the effort to deal with it.

 

[Elledan]

Thanks, Harvey

I'm not trying to fix this mouse because I want to fix it, but because I'm learning to create circuits myself, it's good to analyze some other circuits. If the mouse works after I'm done with it, it's a bonus

Anyway, from the site frizzlefry linked to, I got the datasheet for this IC and I'm currently reading it.