soldering %$@#!!

Discussion in 'General Electronics Chat' started by rollinz34, May 21, 2012.

  1. rollinz34

    Thread Starter New Member

    May 21, 2012
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    my first attempt on a flatron l1730s power board... went from some power to no power, i think i applied to much solder and burnt the board?! anyway how to fix this?
    i used 60/40 rosin core solder
    and a 30 watt iron with pointed tip
    Is the brownish color from the solder or actual damage to board?
     
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  2. praondevou

    AAC Fanatic!

    Jul 9, 2011
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    The brownish colour is flux contained in the solder.

    But it looks like you shorted the two large pads. What component were you trying to replace?

    You may need more than 30W to heat up this large area and get a good solder joint.
     
    maxpower097 likes this.
  3. milesguidon

    New Member

    Dec 4, 2010
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    No, you haven't damaged the board. You've just browned it, which is probably mostly due to burning the flux that's in the solder metal. For a quick fix for stuff like this, here's what I do:

    Heat the solder up, and quickly turn the board *solder side down* and lightly flick it at a table so the solder flies off downward at the table. Make sure the heated solder is not anywhere near your face, and that it is pointing down (so you can't see it). You must do this while the solder is still hot, and most of it will flick off of the board. Only do this for durable boards that don't have a lot of components already soldered on.

    You should look into using a "flux pen" and "solder wick" to help you solder if you're having trouble. Apply flux pen to the surface to be soldered to, and if you make a mistake, apply flux pen to underside of solder wick, place solder wick on top of problem area, and place iron on other side of solder wick (sandwich the wick between the problem area and the iron to suck up the over-soldered regions.
     
  4. KJ6EAD

    Senior Member

    Apr 30, 2011
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    You need a higher wattage iron so you can melt the solder before destroying the board. The large copper fill areas act as a heat sink.
     
  5. DerStrom8

    Well-Known Member

    Feb 20, 2011
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    I pretty much agree with the others, but I've got a question: How thick is your solder? It looks like there was too much flux for the joint, and your iron wasn't able to burn it off in the short amount of time. For that kind of joint I wouldn't recommend anything larger than about 0.1 inch. I use .032", personally, and it works for a wide variety of jobs. Larger solders have more flux, and require irons with much higher wattages. A 30W should be enough if you have the correct solder.
     
  6. rollinz34

    Thread Starter New Member

    May 21, 2012
    2
    0
    Thanks for all the helpful replies,
    1.22mm is the thickness of solder, seemed a bit thick but im completely new to this. Replaced a capacitor, I just used some braid and desoldered the area that should not have been hit with solder. You were right about the area being damaged as i seemed to extract areas of this when extracting the solder.

    What do you call the metallic lines that run vertical on PCB in my picture (ones that were hit with solder)??
    Its a process for me because im self tutoring myself all the terminology and practices...

    So I should clean area of flux with iso and then what exactly should i repair to get power back?

    Thanks again for the help guys!
     
  7. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    7,386
    1,605
    From the picture it looks like the board designer left the traces free of solder mask, then heaped solder onto them to make lower resistance traces. I expect this to be a high current device.


    Isopropyl alcohol is a good safe cleaner. I use it with an "acid brush" (metal tube to black bristles) which I cut down to get a 'stiffer" brush.

    As to what to repair I have not a clue. I would need a schematic and some idea of what it once did and now does not do.
     
    rollinz34 likes this.
  8. t06afre

    AAC Fanatic!

    May 11, 2009
    5,939
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    A suction pump and/or some solder wick will take care of your problem. I can see you are a beginner. Well we have all been there some time. On you-tube, you can find some good lessons for basic electronics soldering. Like how to use suction pump or solder wick. It could be an good idea to take a look at them.
     
    rollinz34 likes this.
  9. KJ6EAD

    Senior Member

    Apr 30, 2011
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    The best soldering videos on Youtube are from "curiousinventor", "solderinggeek" and "jkgam041".
     
    rollinz34 likes this.
  10. #12

    Expert

    Nov 30, 2010
    16,261
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    1.22 mm is .048 inches. Not bad at all.
    I learned to use Toluol or Xylene as flux remover back in the 1970's but several alcohols work well and are safer.
    Completely agree with post#7. The lines are called "traces" and heaping solder on them is a cheap and convenient way to increase current handling ability without buying special, high thickness copper, circuit boards.
     
    rollinz34 likes this.
  11. DerStrom8

    Well-Known Member

    Feb 20, 2011
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    Something I kind of assumed was that you're using flux core solder. I should have asked about that first. If you're using flux core solder, what type of flux is it? I usually use rosin core solder with a 15 watt iron, and I don't have a problem. You might try just leaving the iron on the joint a little longer to allow the flux more time to burn off. If you ask me, 30 watts is more than enough for most applications, but again, it depends on what you're soldering.
     
  12. takao21203

    Distinguished Member

    Apr 28, 2012
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    For desoldering you need a 50W station and preferably not a fine tip.
    Also set the temp. higher for desoldering.
     
  13. maxpower097

    Well-Known Member

    Feb 20, 2009
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    388
    You also can get a brillo pad looking thing you put on the solder and heat up and it sucks up extra solder. Its a good lil thing to have around if you don't have a vaccum. As for an iron if you into soldering look for a used entry level Hakko 936. Lots of immitations and counterfits though so becareful who you buy from. You also have the discontinued Hakko 939 which I have which I call the god of solder irons. All digital, keycard so employees can't change settings. heat elements in the tip so theres no drop off when soldering somethign big. Most people don't know but the pens are compatible from the 936 and 939 . 939 tips run $20 each, 936 which are normal pens with standard tips that are cheap. So its nice to have both pens and use my 939 tips for high precision jobs and stuff that needs the best. But since tips are so expensive if its a bs solder job I put the 936 pen in and use anormal tip. So you can buy both pens for each and use both tips for each. Its just the 936 is a knob, and the 939 is digital.

    Oh and check out the hakko tips. You can even get ones that fit standard chip foot prints so you just put the tip on the chip and it desolders all the leads and the chip pops right off. There basically squares that are hollow inthe center where the chip is but the actually heated tip is the edge of the square.

    One more cool thing about he expensive 939 tips is they come with a calibration number on each tip that will say -7 or +3 or -12. You then go into your settings for the iron and put in the difference to get accurate readings to the degree.
     
  14. DerStrom8

    Well-Known Member

    Feb 20, 2011
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    I would have to disagree with that. If you have the right tools (even just a desoldering pump), a 15 watt iron does just fine. I haven't had a problem desoldering with my iron and a rubber "bulb". No need to go all out on an expensive 50 watt station, in my opinion.
     
  15. Gdrumm

    Distinguished Member

    Aug 29, 2008
    684
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    I see several 220v desoldering guns on Ebay, but only a few 110v, and none for under $50.00.
    Is the USA behind the times on this technology?

    I've got a couple of manual solder suckers, and a bulb type 110v, from Radio Shack, but I'm not happy with either of those. Am I likely to have to shell out $90.00 to $100.00 + to get what I need?
    I have a shakey r-hand, so I need something very user friendly.

    Does anyone have a good lead?
    Thanks,
    Gary
     
  16. ISB123

    Well-Known Member

    May 21, 2014
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    You can buy 110V ones from ebay for 80-100$,in USA you would pay 200$-300$.
     
  17. takao21203

    Distinguished Member

    Apr 28, 2012
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    probably it isnt temp. regulated so gets very hot, you can do a few joints, but then cools down.

    Depends how fast you solder. I often do regular IC pads in a row too, pull of the bridges with the broad tip.

    The rails for large LED matrix (on perfboard) are a pain even with 50W, using cheap chinese lead solder.

    I can remove TQFP44 ICs and all SOIC ICs without tools.
     
  18. DerStrom8

    Well-Known Member

    Feb 20, 2011
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    You're absolutely right, it all depends on techniques, habits, and the types of projects you're working on.

    I bought a variable-temperature Weller and I much prefer that over my pencil-type, but the pencil-type is certainly still usable.
     
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