What is this PCB component

[apostolakisl]

I have a device that let out the magic smoke.  I tore it down and found this brown oblong ball connected by 2 wires to the board.  It is sitting next to a capacitor (white rectangle).  I think the capacitor just got scroched on the outside when the brown thing melted down.  There are no numbers on it (at least not that you can tell now that it is scorched).  There is no writing on the pcb that can be seen.
 
The other thing, do you think the brown thing melting down was an independent event or do you think it probably is the result of some other fault.  In other words, do you think if I replaced it, all would be working again.
 
Thanks!
 

 
 

 

[Frunple]

Looks like a polypropylene capacitor. As far as replacement, always a crap shoot if you're just gonna replace without testing.

 

[BraveSirRobbin]

It may be a tantalum capacitor (look about halfway down THIS web page).  They WILL blow if polarity is reversed (don't ask how I know this)!
 
Was it possible that the power to this unit changed somehow that may have reversed or changed the polarity?

 

[apostolakisl]

It may be a tantalum capacitor (look about halfway down THIS web page).  They WILL blow if polarity is reversed (don't ask how I know this)!
 
Was it possible that the power to this unit changed somehow that may have reversed or changed the polarity?

 
Not from anything a user could have done.  Only a failure of some other component could have changed the polarity.  It let the magic smoke out on power-up a couple days ago.  
 
This is one module from a device that measures a number of things, mostly the concentrations of certain gasses.  The device still boots up and runs, it just runs errors on the stuff that this part is supposed to do.  It is an old device but still well regarded.  Unfortunately, the manufacturer no longer supports it.  So any proprietary part failure would be the end of it.  Brand new machines are a bit smaller and have prettier GUI's but they don't provide the user with any better information, and they cost a fortune, so I'd love to fix this one.
 
But I think you nailed the part.  It looks exactly like that tantalum capacitor.  Thanks.  

 

[BraveSirRobbin]

If this is an old item, it is possible that the di-electric has aged and possibly failed.  Also, tantalums, though they are very 'stable', are finicky about power, especially reverse polarity, surges, and over voltage exposures.
 
Unfortunately, they also fail in a 'shorted' mode rather than open the circuit!
 
I would do a couple of things.  One, test the power system that is providing the (DC) power to your unit.  Also, test any voltage regulators in place on the PC board, or near any power leads.  If you can get an overall picture where details can be seen, I may be able to identify these regulators.
 
If the unit still powers on, test the voltage around that blown cap with a meter to see if it is within the specs of the regulator's output or provided DC supply if possible.
 
It's important to rule out any possible power type failures before replacing this component.

 

[apostolakisl]

Thanks.  I'll do that.  I pulled the capacitor off the board and with magnification and bright light, I was able to discern that indeed it is for sure a 10micro farrad, 35 v capaciter.
 
The unit gave an "overheat" warning.  So perhaps it protected itself.  I doubt it would bother to monitor such things if it wasn't going to do anything about them.  
 
 Thanks.
 
Here is the whole board.  The back just has two capacitors on it, otherwise all is on the front.  Aside from the capacitor next to it, with soot which I think came from the fact that it was next to this part and not internally toasted, nothing else on the board has any sign of overheat.  I should be able to hook this guy up and test the voltage across the voltage regulator as well as where I pulled the cap from.