First time desoldering a connector. Is it ok?

Discussion in 'General Electronics Chat' started by CraiGDaniel, Oct 1, 2012.

  1. CraiGDaniel

    Thread Starter New Member

    Oct 1, 2012
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    I have ventured into soldering and i have desoldered an LCD connector off of an iPod touch 4.

    However i am unsure as to whether i have damaged anything as it wasn't as streamlined process as i thought and i had to scrape some plastic near the traces etc.


    I'm very new to all this so would appreciate any advice!


    [​IMG]
     
  2. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    pic is a little blurry so its hard to tell. But in general as long as you didn't lift the pads off the board or break the traces then its usually fine..

    oh and good job if this is your first time and you didn't lift a pad... :)
     
  3. CraiGDaniel

    Thread Starter New Member

    Oct 1, 2012
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    Thanks mcgyvr that reassuring.

    Pads stayed on luckily ! The connector had a plastic base so i just used the iron to melt it all off - i worried that i may have damaged something though as i used a metal tool to scrape off some plastic that remained behind but it doesnt seem as bad as i though!

    Cheers
     
  4. strantor

    AAC Fanatic!

    Oct 3, 2010
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    seriously. I won't even attempt to solder that tiny stuff inside I-XXXN devices.
     
  5. CraiGDaniel

    Thread Starter New Member

    Oct 1, 2012
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    It isn't too difficult but good magnification is needed :)
     
  6. orbiter

    Active Member

    Jun 17, 2010
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    As mentioned it does look ok, as far as can be seen anyway :) Also though.. Make sure you clean the pads, and use plenty of flux when you refit any parts.

    If you're going to be doing this kind of thing quite often then an electronics hot air gun can be a great tool to have in your kit. I tend to use an iron for similar stuff but it can be quite tricky with certain components, especially in tight spaces.

    In fact I was working on a I-P**** 4 not too long ago (repairing the mainboard) a couple of tiny 0402 parts had been knocked off by someone who'd been digging around with a lever trying to open up the phone. And trying to re-flow such parts in a tight space is a right PITA, so I grabbed the hot air gun, and with a very low flow rate, had some new parts back on in a short time. Unfortunately though that wasn't the reason the phone stopped working :(
     
  7. CraiGDaniel

    Thread Starter New Member

    Oct 1, 2012
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    Good advice thank you. I have an Aouye 968 Hot Air Reflow Station so hot air could be used just not sure how to use it properly.

    I've fixed over a hundred I-4's and had self repairs in with damaged parts like you said, where someone had been careless with opening tools. Unfortunately electronics and soldering was nothing i had ever gone into so i outsourced that work.

    Do you know of any good places to learn about mobile phone electronics and soldering small parts. For example i have no idea what an 0402 is.

    Also where in the england are you from? I'm in Essex, makes a change to see someone from this country on one of these boards" !
    Lol Cheers
     
  8. orbiter

    Active Member

    Jun 17, 2010
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    Sorry.. 0402 etc just refers to the package size of the component I was referring to. You can check this link for details on such package sizes. Scroll down for a graphic reference scale etc http://en.wikipedia.org/wiki/Surface-mount_technology

    I can't help with references to sites on mobile repairs as I don't know of any dedicated to such work off the top of my head, I tend to just Google anything I'm stuck on (which is most things really :) )

    I'm near Southport, North West UK.

    Cheers

    John
     
  9. CraiGDaniel

    Thread Starter New Member

    Oct 1, 2012
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    Very nice wiki link. Had a good read. I can tell this is not something you learn over a weekend !!


    Do you have any tips or good methods to fit the new LCD connector when it arrives. I'm a bit confused on the way to do it.

    I was thinking of tacking the corners down with a bit of solder then dragging the iron across the pins, is this the best way or?


    Many thanks.
     
  10. orbiter

    Active Member

    Jun 17, 2010
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    Sure.. If you're used to drag soldering, that should work fine. However If your not sure how drag soldering will go or you've not had a lot of practice with that. Just clean all the pads down properly, coat them with plenty of flux, then tag solder two opposite outer-most pins on the LCD (to locate it correctly) Apply more flux.. Then apply heat & a small amount of solder to each pin separately using narrow gauge solder, and a narrow tipped iron.

    If your not fully sure on the techniques, just watch a few of the SMD/SMT soldering videos on You Tube. You'll pick the technique up in no time. It helped me a lot

    Good luck with your project.

    Cheers
     
  11. Kermit2

    AAC Fanatic!

    Feb 5, 2010
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    I learned a trick using a thin .001 feeler gauge.

    Trim it with some sharp scissors to get a short 1/4 inch or 6mm 'finger' on the end. The width needs to be small,, just like a finger shape.

    Slide this finger in behind the pin you are desoldering and heat the tip of the pad. When the solder melts and with the iron still heating the pad. slide the feeler gauge between the pad and pin. If you tear the gauge just trim it again and try it anew.

    This works best if the solder is already mostly removed, as with solder wicking products. Stainless steel is best, but regular steel(rusting kind) will eventually get soldered to a pin or pad if you don't keep it constantly cleaned with WD40 or similar product.
     
    THE_RB likes this.
  12. THE_RB

    AAC Fanatic!

    Feb 11, 2008
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    Thanks for that tip Kermit2. :)

    I've been desoldering things professionally for 25 years (a lot of appliance repair) and had never heard of anything like it. I'll look out for a cheap set of stainless feeler gauges and try it.
     
  13. CraiGDaniel

    Thread Starter New Member

    Oct 1, 2012
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    Another things guys..

    I have the Aouye 968 Soldering Station.


    It has hot air rework and i am struggling to use it to remove surface mounted components.


    I set the hot air station to 350c and that doesnt even melt my solder wire - i need to have the station set to 480c (max on station) and hold on the solder for about 30 seconds for it to melt.

    I can actually remove components on the board @ 480c but any lower and it will not. Is this the normal temp for hot air removal of SMD components? I am using good flux too.
     
  14. orbiter

    Active Member

    Jun 17, 2010
    58
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    Sounds like there's something not quite right with the hot air part of the station. For example even working with lead free solder I can set my CSI hot air gun to around 400*C and It will help remove most components, apart from say ones that are attached to a large ground plane etc.

    Perhaps try using a suitable temp probe and place it directly in the air guns air flow and measure the temp. It could just be time for a new heating element.
     
  15. CraiGDaniel

    Thread Starter New Member

    Oct 1, 2012
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    So you say 400c would be your average temperature for removing chips and what not with hot air? Roughly how long do you take to heat the solder up before attempting to remove it?

    Also the station is brand new so hopefully its not defect !!
     
  16. orbiter

    Active Member

    Jun 17, 2010
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    To be honest I've not measured the actual air temp from my gun but I know the digital display reads around 400*C so I at present I just assume it's close.

    I set the gun to around 400*C then move in gradually whilst pre-heating the solder/board. After a couple of minutes I can move the 2.5mm tip in to around 2cm or so and remove the part.

    I think the fact that you're having to have your station set to full heat just to remove some SMD parts may be an indication of a problem. I'm assuming here you've tried various air flow speeds and heats already for the results you're expecting from the gun?
     
  17. CraiGDaniel

    Thread Starter New Member

    Oct 1, 2012
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    What you said sounds about right.


    I'm not using any tips - i lost the tips for the hot air gun that came with the station. Could lack of tip be causing this? I know it came with some small nozzles to better direct the hot air, at the moment im just using the bare hot air gun and the nozzle is quite large and round.

    Infact holding the heat gun about 5cm from my hand @ 300c doesn't burn me and i can hold it there all day. Shouldn't be normal?


    Yes i have tried max air flow, min air flow etc it really doesnt seem to make any difference.
     
  18. orbiter

    Active Member

    Jun 17, 2010
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    Tips will definitely help with the air flows concentration & direction, otherwise you'll just be spreading heat everywhere which is not always a good thing, unless that's what the work requires. Try say a 5mm nozzle first and see if that improves things.

    If not, I think I would be contacting the company you bought the unit from, and telling them it's not working as expected. See if they can offer some help... They may just send out a new heating element if they've had an issue with them or something.
     
  19. CraiGDaniel

    Thread Starter New Member

    Oct 1, 2012
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    I've got a feeling a tip will make a huge difference but like i said i've lost them all. :(


    Can't seem to get replacement ones either - :(
     
  20. orbiter

    Active Member

    Jun 17, 2010
    58
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