Do VIA pads have to be replace for connections?

Discussion in 'General Electronics Chat' started by GPhillips, Jun 19, 2016.

  1. GPhillips

    Thread Starter New Member

    Jun 19, 2016
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    This question is more for future reference, however I thought I'd ask anyway.

    The other day I saw a motherboard with some of its pads ripped off, and there was no traces directly attached to it, so I believe it was VIA connected. My question is that if someone were to connect wires to those points, would the pads have to be replaced first, or it there an alternative?

    I read somewhere that this product can attach wires without having to replace the pad itself, can anybody confirm this?

    The pad was almost microscopic, so I take it that it wouldn't be easy to replace.

    Thanks.
     
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Normally the via has a centre hole which can be filled with a small gauge wire to do the transfer to each side.
    Max.
     
  3. GPhillips

    Thread Starter New Member

    Jun 19, 2016
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    So I assume that once old adhesive is removed from where the pad was, small gauge wire along with the product I linked could act as a new pad? Thus no need to replace the pad itself?
     
  4. dl324

    Distinguished Member

    Mar 30, 2015
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    It depends. Motherboards typically have more than two layers. If the via was used for an interlayer connection, you have to connect to the barrel used for the plated through hole. If the barrel was damaged you have to find all inner layer connections and connect them with jumpers. I used to do this on boards with up to 8 layers and it can only be done if you have schematics.
    Don't see why it wouldn't work as long as you can make reliable connections. I've used this conductive pen or adhesive backed copper foil.
     
  5. GPhillips

    Thread Starter New Member

    Jun 19, 2016
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    @dl324

    Thanks for the info and confirmation. Good to know, as fixing those pads don't look like a walk in the park.
     
  6. MaxHeadRoom

    Expert

    Jul 18, 2013
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    If it is just a double sided board I take a small conductor from one side to the other clean the nearest common trace and solder to it or a component pin.
    Max.
     
  7. GPhillips

    Thread Starter New Member

    Jun 19, 2016
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    Thanks, will keep that in mind.
     
  8. SLK001

    Well-Known Member

    Nov 29, 2011
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    You don't give enough information. If the motherboard is of HDI construction (and a lot of them are that today), then your via may be of the micro-via type, where the connection is only to the next layer underneath. No wire-through-the-hole will fix this, because there is no hole. What you need to do, is get the datasheet for the device that used to attach to that pad and find out what that pad does. You have maybe a 0.01% chance that the pad is a NO CONNECT. If it is not, then you'll have to go to the schematic and find where that pad is connected and wire a connection from the pin to that other connection's end.

    On a motherboard, with this type of damage, I would say that you are hosed.
     
  9. GPhillips

    Thread Starter New Member

    Jun 19, 2016
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    @SLK001

    Sorry for the lack of info, I actually called the guy up whose house I was at, and he said I saw the back of either an Xbox 360 or PS3 board that he soldered incorrectly to. For interest sake, would it work for those motherboards? I can only think it was for modding purposes.

    Those pads were probably a touch bigger than a pin-head.
     
  10. GPhillips

    Thread Starter New Member

    Jun 19, 2016
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    Also, if the wire-through-the-hole solution isn't applicable, will the epoxy method still work?

    Just wondering if it's an all or nothing situation, thanks.
     
  11. SLK001

    Well-Known Member

    Nov 29, 2011
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    Pictures, pictures, pictures. Did I mention pictures?
     
  12. GPhillips

    Thread Starter New Member

    Jun 19, 2016
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    I managed to get these 2 snaps of the particular points.

    These pics are of the 360 motherboard, with the pads still intact.

    Top.png Bottom.png

    For example, with the FT6U points. If someone wanted to solder wires to those points on the bottom of the board, with the pads being ripped or damaged. Would they first have to be repaired, or would the epoxy or wire-through-the-hole fix work?

    Thanks again.
     
  13. Techno Tronix

    Member

    Jan 10, 2015
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    It's fine, and it's also a good practice because you save an useless vias, so pads and holes that in addition would have to be made conductive, with a wire or with a metal fill.
     
  14. SLK001

    Well-Known Member

    Nov 29, 2011
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    I believe that the FT pads are just factory test points. No need to fix them.
     
  15. GPhillips

    Thread Starter New Member

    Jun 19, 2016
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    I decided to delete my last 3 posts, as it was starting to get a bit much.

    Thanks for the feedback, however I'm still unsure of something. If the pads were to be ripped or damaged, would the epoxy and/or wire-through the-hole fix work for the 360 motherboard?

    As I don't know if @SLK001 meant no need to fix them for ordinary function, or no need to fix them to attach wires.
     
  16. ElectronicMotor

    Member

    May 1, 2016
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    I have just joined this discussion.
    What is VIA ?
     
  17. bertus

    Administrator

    Apr 5, 2008
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  18. SLK001

    Well-Known Member

    Nov 29, 2011
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    There is a possiblity that the pads with the long traces do not even have a via underneath them. A test pad is brought out from some point on the board to a generalized area so that a flying probe can reach so that voltages/ other functions can be easily tested.

    I have no idea as to the "attach wires" thing and without a schematic I won't even guess.
     
  19. GPhillips

    Thread Starter New Member

    Jun 19, 2016
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    Well, thanks anyway. Like I said, people solder to those points for modifications, I don't know if that says anything.. Also, I've seen people solder to the small traces connected to those points when the pads get damaged for whatever reason. I just thought it would probably be easier using an epoxy to connect wires straight to the board, instead of trying to repair the pad and then soldering wires to it from there, as those pads would need a microscope to be fixed (if possible) or to even solder to the traces.

    Not sure if I'm making sense..
     
  20. GPhillips

    Thread Starter New Member

    Jun 19, 2016
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    I've been thinking, and well, since people solder to the pads on the top of the board as an alternative when a bottom pad gets damaged, wouldn't that make it a buried VIA? As it's conductive on both sides and not just one, plus both points theoretically receive/send out the same information.

    So unless I've got this completely wrong, the point on the board being conductive in the first place, would mean the epoxy would too be conductive in it's place? Thus allowing connection to a wire possible, as it would be a "glue" and act as a pad at the same time?

    I've been trying to think about this logically, so I'm not entirely sure, but does that make sense?

    Can anyone confirm/verify? Vice versa..
     
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