What to do with this super-ugly solder joint o' mine...

sweetbeats

sweetbeats

Reel deep thoughts...
All pride aside, and you'll understand why when you look at the pic below, I need help.

I'm a little frustrated. Trying to solder a 1/4W resistor onto the Mother PCB for my Tascam 58 reel-to-reel. This is the second attempt and I'm just making a mess. I have limited SM soldering experience, but I do have some and I've never encountered this problem, and I've made up lots of cables which is to say I'm comfortable with a soldering iron but...

Okay. The foil has lifted and broken, so that's one question: what to do about that. The second question is I'm trying to figure out why the solder is not really welding to the foil (this is happening with the joint at the other end of the resistor as well). It sort of is but in the picture you can kind of see how it has puckered under. The solder definitely has an affinity for the lead on the resistor...so I'm looking for suggestions there about what I might be doing wrong. This is the same iron that I've used for every single solder joint I've ever done. I'm using 0.032" 60/40 rosin core solder.

I'm used to placing the tip of the iron on the work for a brief moment and then feeding solder into the joint and holding the tip on the work until I see the solder wick into the joint. This joint don't wick...the solder just clings to the resistor lead. Couple days ago I soldered an LED socket onto a channel PCB on my mixer...no trouble at all. I'm making a mess of this one...

ugly%20solder%20joint%20%232.jpg
 
Dirty leads maybe? Try a tiny drop of liquid flux (apply with a toothpick) before resoldering to clean the parts. Solder does not take well on dirty, corroded, greasy, waxy surfaces. And clean the tip of your iron frequently, a quick wipe across a damp 100% cotton cloth usualy is enough (while the iron is hot) for this. A little contamination can really mess up an otherwise perfect soldering job.
 
There's obviously something inhibiting the solder attaching to the trace. What I'd suggest is first clean up all the excess flux that's around the resistor tails with a cotton bud (Q-tip) and metholated spirits or alcohol and the sharp tip of an Exacto knife, it may be easier if you remove the resistor to do this. Then with the Exacto, carefully expose the traces' copper surface a few mm (approx., 1/4") back from the holes and see if you can tin the exposed copper. If that works, then reinstall the resistor and bend the tails so that they're contacting the tinned trace and solder to that.

Be sparing with the amount of heat you apply to the traces as too much may cause them to lift. The off cuts of resistor tails are always handy to repair damaged traces.

:cool:
 
+1 for our aussie friend...

cleaning the area is the most important part of removal... if you're lifting traces you're on the thing too long...


couldn't wait for the new station???
 
Thank you everybody!

couldn't wait for the new station???
Click to expand...

:D:D:D:D

Welllll, its like this: I got a new tip for the old iron and I was removing some components off the PS PCB on the 58 and it was working really well, so I got overconfident, but it sounds like without additional prep work no iron would have done the trick...

I think the trace originally got damaged because one of the tails was still adhered when I pulled the bad resistor out and I didn't realize it until it was too late, so it got tweakered. And yes I think I kept heat on too long trying to get the solder to wick to the trace.

So, just to be clear I am going to:

  1. Remove the resistor
  2. Use a knife, swab and solvent to clean up the area
  3. Use the knife to expose a good section of trace approx. 1/4" back from the hole
  4. Clean the exposed section with a swab and solvent
  5. Tin the exposed section (is this where liquid flux may come in handy?)
  6. Solder away after fashioning the tail to mate with the exposed section of trace

Have I got it?

Thank you so much for the replies...learning, learning, learning!
 
Yes mate, that pretty well sums it up. If the solder you're using is "resin cored" I wouldn't worry about the liquid flux unless you still experience difficulties with tinning the exposed copper. Unfortunately, it going to be a case of "suck it and see" ;).

ChrisO :cool:
 
I noticed that I'm even having some trouble tinning my iron with the solder I'm using...maybe that's part of the problem? Maybe my iron needs to be cleaned and re-tinned?
 
If it's fairly new solder it could be the ROHS compliant stuff which I believe can be "problematic".........regardless, it's a case of gentle perserverance:).

Chris :cool:
 
Mmmm...yeah, I think I got this spool within the last 12-18 months.

Gentle perseverance...hammer mechanic...he no fit I make he fit...all synonymous. :D
 
You might also want to tin the leads on the part you are installing. This helps heat transfer faster so you don't have to keep the iron on the board as long. Tinning the leads helps a lot when working with very small wires (rewiring pups for instance) and when working in tight spaces or when you need to get in with the heat then back out as fast as possible.
 
It isn't a new roll of solder is it? One of the other Technicians at work mentioned that there is a move towards lead free solder and he had a roll of it. It was tough to solder with and the connections quickly dulled and had a look of cold solder joints. It just made me think of the problem you are having here....oops-I missed the post above stating the same point-nevermind~
 
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