JanusRec

Replacing pulled smd pads
« on: May 01, 2009, 06:06:56 AM »
Replacing the smd opamps in my motu converter I just pulled some pads. Really bad for me: Some pads of the main output Ic are destroyed.

In another thread (Removing a TSSOP chip) I read  as if it is possible to replace the pads:

... We replace pulled pads all the time but it can take 20 min. for each pad using a microscope. 

Solder wick can be used but I don't trust it. 

Vetsen

Does anyone know how to do it? And for another project it would be also nice to know how to attach wire to these tiny copper traces.

Thanks, Sebastian


helterbelter

Re: Replacing pulled smd pads
« Reply #1 on: May 01, 2009, 06:35:27 AM »
At work we have copper ribbon, especially for repairing damaged traces. We usually scrape the mask off the track where the track is still good, apply solder to that part of the track, and solder the ribbon on top of that. Then go to the part where it can be reconnected, and  do the same. Finally, we glue the ribbon to the PCB with DP110 .

And indeed, solder wick can be used for cleaning the pads, but be sure your iron is hot enough, otherwise you can be sure you tear the pads off.

For removing SMD IC's, I usually use a hot air soldermachine (I'm so fortunate we've got one at work !).

I hope it makes sense what I'm telling here, my technical english ain't that good.


What kind of Motu do you have... May I ask ?
I've got a 24 I/O, and I'm also thinking of an opamp/ cap upgrade.

JanusRec

Re: Replacing pulled smd pads
« Reply #2 on: May 01, 2009, 07:04:11 AM »
So there is hope  ;)

Ok, so this special copper ribbon, how thick is it? And is it flat or round shaped? And I could use different glue, couldnt I?

What kind of Motu do you have... May I ask ?
I've got a 24 I/O, and I'm also thinking of an opamp/ cap upgrade.

I have a 828mkII firewire with a lot of NJM4580s and 2115s inside which I replace with 5532s (some people also use BB2134s or even better chips - but too expensive for me as you need 40 or 50 of them). I already replaced many of the chips and on the inputs it really make a difference, on the outputs I'm not sure yet. Your 24 I/O has the same ICs I think...

And what about attaching wire to a copper trace? Because I want to repower the clock with a very clean psu which should make a bit difference, too. Read about it in another forum.

helterbelter

Re: Replacing pulled smd pads
« Reply #3 on: May 01, 2009, 07:58:31 AM »
There's always hope  !  ;)

Yes, you could also use wire. At work we use the ribbon mainly because of the IPC standard that we use for production. Wire is also accepted by the IPC standard for modification, but not for repairing tracks. But you don't have to follow the IPC standard, and wire is good too. But be sure that you glue the wire to the print, and avoid wires crossing.

The ribbon we use is flat. It's actually like the normal tracks on PCB's, just a tiny bit thicker. The glue... Well, use something that will last, and that doesn't affect the protective layer of the PCB. DP 110 is a 2 component glue. Or use nailpolish if it's just a small piece of wire/ ribbon, that should last forever ( I think).


When I do my Motu, I'd probably go for just a couple of channels to begin with. And then go for the best, haha !

Anyhow, good luck with repairing, I'm sure you'll do a great job.

bobschwenkler

Re: Replacing pulled smd pads
« Reply #4 on: May 01, 2009, 03:26:36 PM »
If you're stripping the soldermask off of a trace I'd reccommend buying and using flux on the exposed copper. This is really helpful in getting the solder to adhere to the bare copper IME.
Complete 312 to M1 type preamps, and anything in between - hundreds sold - The Hybrid 312: www.schwenkleraudio.com/312

www.dubnarcotic.com
www.schwenkleraudio.com

JanusRec

Re: Replacing pulled smd pads
« Reply #5 on: May 01, 2009, 06:20:17 PM »
Thank you guys - it worked!  :)
Although it could look a lot nicer...
I soldered a single wire out of a braid to the exposed copper; than fixed with superglue. Not the professional way, I guess - and that's the way it looks - but I'm so happy to have my main outs back!

helterbelter

Re: Replacing pulled smd pads
« Reply #6 on: May 02, 2009, 05:48:29 AM »
 :)

Great !

hobiesound

Re: Replacing pulled smd pads
« Reply #7 on: May 02, 2009, 06:48:33 AM »
Thank you guys - it worked!  :)
Although it could look a lot nicer...
I soldered a single wire out of a braid to the exposed copper; than fixed with superglue. Not the professional way, I guess - and that's the way it looks - but I'm so happy to have my main outs back!

 hey man this is diy, it doesn't matter how it looks as long as it works (well..).  ;)

check out this dutch guy on you-tube and his tidy soldering ! http://www.youtube.com/watch?v=C_IdEBT4uf0

greetings,

Thomas

helterbelter

Re: Replacing pulled smd pads
« Reply #8 on: May 02, 2009, 06:59:13 AM »
Hey Sebastian, you mentioned superglue.... I'm not sure if that's a good choice for the long run... It isn't heat resistant for instance, and I can imagine that it looses strength after a some time.... But if the wires aren't long I don't think it will cause any problems.

Hobiesound, nice vid !

JanusRec

Re: Replacing pulled smd pads
« Reply #9 on: May 05, 2009, 07:05:39 AM »
Hey Sebastian, you mentioned superglue.... I'm not sure if that's a good choice for the long run... It isn't heat resistant for instance, and I can imagine that it looses strength after a some time.... But if the wires aren't long I don't think it will cause any problems.

Hobiesound, nice vid !

The wires are only 5-10mm; glued and soldered: It should last for a while ;)


 

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