SMD removal , carnage beneath, options?

[grendelrt]

I am doing a cap replacement on my Turbo Duo and when I removed this SMD it was pretty bad underneath. I tried cleaning with isopropyl but it didnt do much. What are my options here? I have done much with SMDs, can i just scrape off where the pad was and solder to copper underneath?

 

[DNSDies]

That looks pretty bad.
Electrolytic fluid from the caps probably leaked out.
Iso won't do much to corrosion, just get the dust and surface dirt off.
I'd use a proper contact cleaner and hope for the best.

Wost case, those contacts are dead and you'll have to trace them to their next connection and solder a wire in to form a new connection, unless the cathode of those capacitors were grounded, in which case you can just expose some ground plane nearby and use that.

Do try and gently clean it though. The corrosion will get under the protective solder mask and spread if you don't.

After you're all finished, you might consider using some brush-on solder mask to protect it for the forseeable future.

 

[Sypth]

Excuse the paint edit, but you should be able to just scrape some of the mask off at that point, I'm assuming that's where the trace leads too, but double check obviously. Then run a jumper wire from there to the cap, simple as that. Other wise as other people suggested, try cleaning the point with an abrasive cleaner to get the corrosion off the pad.

 

[grendelrt]

Yeah the left side is ground, so I am guessing I can ground that somewhere. Right side was positive, let me edit the pic a little more its hard to see, but that little dot above the hole is solder, is that connected to the same trace as that hole you think?

 

[Sypth]

By the looks of it yes, but best practice is to check with a multimeter.

 

[grendelrt]

By the looks of it yes, but best practice is to check with a multimeter.

Yeah that's what I ended up doing, have 50 of the 55 replaced. Going to pray and start her up in a bit :O

 

[grendelrt]

Yeah that's what I ended up doing, have 50 of the 55 replaced. Going to pray and start her up in a bit :O

So did a recap because of a low sound issue on cd games, didnt fix it...le sigh

 

[Sypth]

Sorry man, I know for a fact if you don't clean the solder pads well enough you'll still have issues. I had to cap my duo twice to learn that out. That and the way I mounted the caps the first time was dumb as hell. But, you live and learn.

 

[grendelrt]

I posted over on PCengineFx and Keith has replied a couple times, hoping he can help me track down the issue.

 

[grendelrt]

Dont know if anyone cares, but I found the issue leading to the low sound. One via near IC521 (4558 opamp) was bad and the chip wasnt getting a proper ground. YAY!!

 

[DNSDies]

Glad everything worked out!

Changing those caps out wasn't a wasted effort either. They all fail eventually, and it looks like yours had a leak that was luckily addressed before it got too bad.

You should play some Rondo of Blood to celebrate and put those repairs to work.