View Single Post
Old Oct 31, 2012, 08:30 AM
Couchking is offline
Find More Posts by Couchking
180CFX - Nano CPX - DX6
Couchking's Avatar
United States, CA, Laguna Niguel
Joined Nov 2010
225 Posts
Originally Posted by i812 View Post
It is difficult to see from the somewhat blurry photos, but it looks like they are the "classic" images of what happens when someone "parks" their soldering iron for too long, and/or excessively man-handles parts and ruins solder pads and traces when trying to remove parts.

Solder bridges (I'm not certain you have any) can be removed by careful reheating and allowing excess solder to "wick" onto the tip of a "clean" soldering iron or onto a bare wire. Clean tip of soldering, or cut of tip of bare wire and re-wick as required to remove all excess solder.

Lifted/Missing solder Pads (it looks like you may have a few at the Power Lead connections on both sides of the PWB) can be made functional by the Jumper-wire technique. Most of the PWB traces can be improvised by solder tacking 30 AWG insulated wire from component lead to component lead. BTW, I believe most people lift or ruin Solder Pads or traces is from using excessive manhandling of parts when trying to remove them from the PWB. Probably the best way to remove "stubborn" through hole parts from a PWB is to "wick" (as described above on how to remove solder bridges) and remove the existing solder from the joint, prior to gently removing the part. Using excessive force to "rip" the part off the PWB, is probably the easiest way to ruin a solder pad or trace.

One of the most important things to learn about soldering is DON'T CAMP. Just heat the solder joint long enough to melt the solder joint, then LEAVE. You're not trying to "roast" stuff, you're only trying to "wet" (turn solid crystalline solid into it's liquid phase) the solder, any additional heating after the melting point will not make the solder "wetter" (more liquid), it will only raise the temperature. When soldering you only want to use enough heat to melt the solder, not raise the temperature much more than the melting point. "Camping" with a soldering iron, should only be done for roasting things like marshmallows, and hot dogs, not electrical parts.

I can't tell for certain by looking at your blurry photos, but from the first photo on the left, it looks like both Power lead solder pads on that side of the board are questionable (no longer making good electrical connections). If so, I would simply improvise a new/extra electrical connection from each power lead to the Capacitor (yellowish looking part to the left of Power lead solder pads)

I can't tell for certain by looking at your blurry photos, but from the second photo on the right, it looks like both Power lead solder pads may be missing (not making electrical connections) on that side of the board. If so, then I'd use the 30 AWG Jumper Wire repair technique. Without assembly drawings giving component names, it would be difficult and time consuming for me to describe the required "From .... To ..." Jumper Wire connections. It would be much simpler to have someone take a close-up photo showing the traces on a good PWB, so you can inspect and identify where all the required electrical component connects should be, as well as what is NOT supposed to be connected. I would take a close up photo of a good PWB for you to compare against, but I don't have the proper equipment. If you want to attempt do the micro-soldering repair, then perhaps you can request someone post a close-up photo of both sides of a a good PWB?

Finally, some of the electrical parts in your photo look like they are discolored. The discoloration may be a sign that the electrical part may have been heated to much, and may have been internally deformed/damaged. Most electrical parts are designed to withstand some heat (enough heat AND for as long a time to melt solder, BUT not for extended time periods - i.e. NO CAMPING )

Soldering is fairly easy to learn and do; however it is best to learn on scrap boards, because if you learn on your own like I did (last century), you'll learn from trial and error. It was easier to learn how to solder last century, because the electrical parts and PWB traces back then were about ten times larger. Today, electrical circuit board rework requires better vision, steadier hand, more patience, and smaller soldering tip (actually most of the rework on this board would probably best be accomplished with a Hot Air Reflow Nozzle).

If any of y'all in the US have boards that you'll be trashing, please give them to me. I'll gladly pay for the shipping (should be about $2 USPS First Class Mail). I have a few boards someone asked me to fix but they are missing parts (connectors, FETS, etc).

I'd offer to fix your board, because it looks like it only needs re-soldering and maybe some extra Jumper Wire; however, I don't think it would be fair to fix yours before I fix the others that I have.
Thank you for the thorough reply, I really appreciate you taking your time out to explain the process. I probably did leave my iron on the pcb a little too long, and I'm not too sure I have the skills needed to repair it. I'll try repairing it on my own as per your instructions, but just incase I went ahead and ordered an extra one as well. Thank you again, it's honesty people like yourself that make RCG what it is today.
Couchking is offline Find More Posts by Couchking
Reply With Quote