tried soldering new microswitch

Discussion in 'General Electronics Chat' started by ElectronicBear, Jul 5, 2015.

  1. ElectronicBear

    Thread Starter New Member

    Jul 5, 2015
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    I am a beginner at soldering so I'm asking some advice if I made some kind of common mistake.

    I tried soldering a new microswitch (http://www.amazon.com/D2FC-F-7N-Switch-Microswitch-Switches-Logitech/dp/B00HPL57JQ) to the pcb of my mouse but it didn't work. Is it possible I damaged the board with excessive heat? the only other thing I can think of (apart a faulty switch) is that I did not use flux so I wasn't sure the solder went all the way in to make contact with the board tracks.

    I'm thinking to remove the solder and try again with a different switch. should I buy some flux?

    see picture here http://www.filedropper.com/20150705194020

    thanks
     
  2. dl324

    Distinguished Member

    Mar 30, 2015
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    Too much heat can cause pads and traces to lift. Can't really tell in your case, could just be your technique resulting in solder blobs.

    You need to have your soldering iron tip tinned, heat pad and switch lead at the same time, apply solder when hot, feed solder until you have the desired fill. Process shouldn't take more than a 3-5 seconds, but most components will tolerate 10 seconds. Use a solder with a flux core.

    Please reduce resolution of photos and upload to this site so potential viewers don't need to go to another website and enter a code to download your high resolution file.
     
  3. ElectronicBear

    Thread Starter New Member

    Jul 5, 2015
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    sorry didn't notice it wasn't a free website. here's a smaller version. I had a hard time melting the original tin so I'm sure I kept the iron there for rather longer than 10 seconds. the 3 feet I soldered are in a row by tp9 and tp5
     
  4. dl324

    Distinguished Member

    Mar 30, 2015
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    What is the tin/lead composition of your solder? Both 60/40 and 63/37 will melt at around 360F/183C. What is the wattage and temperature of your soldering iron? 600-700F is a typical soldering iron temp. Are you using the iron to heat both the terminal and pad simultaneously and applying solder to where the pad and terminal touch, and not to the iron?

    From the looks of the solder, either the pad isn't getting hot enough; or the pad has been lifted.
     
  5. ElectronicBear

    Thread Starter New Member

    Jul 5, 2015
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    I have a $10 gas iron that came with solder from Harbor Freight. the solder really looks like this lead-free rosin core (http://www.harborfreight.com/welding/soldering/lead-free-rosin-core-solder-69378.html). I don't know the tech specs, but the new solder I put was melting.

    I am guessing that the pads you're referring to are the cylinder metal blocks through which the feet of the previous microswitch were going through. I was having a hard time desoldering, and I thought those blocks (that were flush with the pcb) had to be removed, so I did.

    So it seems I may have lifted the pads by mistake, and when I tried to solder the new switch, the solder was balling up on top of the feet. If that's the case, it maybe explains why the switch wasn't working, as I didn't make contact with the tracks because the pads are missing.

    is there a way I can fix it?
     
  6. blocco a spirale

    AAC Fanatic!

    Jun 18, 2008
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    If you removed the pads, what do you think you were soldering to?

    One solution is to glue the switch to the board with epoxy resin and attach thin wires between the switch terminals and wherever the pads were attached.

    This will require a level of soldering skill.
     
  7. dl324

    Distinguished Member

    Mar 30, 2015
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    If the traces to the missing pads are on the top side of the board, you might be able to drill holes near them and use wire jumpers through the circuit board to connect to the terminals on the switch. If this is a multi-layer board, you may require additional jumpers to restore inner layer connectivity; doing that would likely require a schematic or an undamaged board.

    I have a butane powered iron, but have never had occasion to use it so I can't give you any usage tips. However, I would recommend that you perfect your technique on a sacrificial board to minimize future mishaps. Single sided boards typically won't have plated through holes and board material would be something other than fiberglass (e.g. CEM1).
     
  8. kubeek

    AAC Fanatic!

    Sep 20, 2005
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    Or you could find out where the pads were supposed to go and replace with a piece of wire.
     
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