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As partly derived from the following question: How to solder under already soldered parts?: I have the same problem as described in the other question (unsoldered wiring through the pcb, now no possibility to solder the pins of the adapters on the upper side of the adapter). But unfortunately the solution described in the other question does not work, because I can not uplift the restricting parts on the adapter (see also pics). I already tried to solder several wires on the pcb vias and connect them to the adapter pins, but that works only on a small adapter. Is there another possibility?

Pictures: enter image description here enter image description here

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  • \$\begingroup\$ You need either plated through holes, or to design your PCB to take into account the fact that you can't get at the component side of the holes. \$\endgroup\$
    – Majenko
    Dec 6, 2014 at 15:28
  • \$\begingroup\$ That is too late now, the pcb has been fabricated, but I did not know that the holes where not plated, therefore I simply soldered the adapter on the board... \$\endgroup\$
    – arc_lupus
    Dec 6, 2014 at 15:30
  • \$\begingroup\$ Then maybe you should use a better fabricator - one that makes a proper PCB. \$\endgroup\$
    – Majenko
    Dec 6, 2014 at 15:33
  • \$\begingroup\$ @Majenko: Next time, yes. But at the moment I am looking for solutions for my current problem... \$\endgroup\$
    – arc_lupus
    Dec 6, 2014 at 15:34
  • \$\begingroup\$ Remove the whole connector, then "plate" the holes through with thin strands of wire. Solder the connector in from the underside as per normal. \$\endgroup\$
    – Majenko
    Dec 6, 2014 at 15:57

2 Answers 2

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Actually, you're in luck. Your board uses two kinds of connectors: 1) board-to-board and 2)D-subminiature.

1) The board-to-board connectors. - Using VERY sharp, small wire cutters, cut away the plastic. Be slow and gentle. Use the side of the connector pins to guide the base side of the cutter. With the plastic removed, partially insert the connector pins into a spare female connecter. Just barely engage the ends of your pins to hold them in place, then use a fine-tip soldering iron. Since you can access both sides of the connector, this should be straightforward. The wire cutters you need are specifically call flush wire cutters. Regular old diagonal cutters will not do. Cheap is bad in this application.

2) The D connector - Because the plastic around the pins is elevated, you can do the same sort of surgery as on the board-to-board connectors, and the same sort of soldering. It's harder because you have to go between the outer layer of pins (from the upper set of contacts), but it is possible to get a fine-tip soldering iron which will do the job (Radio Shack and Home Depot are not appropriate sources), and the job is made easier by the fact that, unlike the other connectors, the two rows of PCB pads are staggered. Even if the tip contacts the upper pin leads, the spacing is wide enough that you won't bridge them with solder, and even if you do you can remove any solder traces. You'll also need fine solder for this, .025 dia or less. The trick is to push the soldering iron tip in horizontally while feeding the sold in from above. Steady hands are needed. An Xacto knife is also useful for trimming away the plastic.

I hope you don't have many of these boards to modify.

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  • \$\begingroup\$ I have only this board, and I don't want to spend more time to wait for another board (~estimated time one month...) \$\endgroup\$
    – arc_lupus
    Dec 6, 2014 at 19:16
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I have to tell you that you should cut your losses now and come back around on this project and get yourself a right and proper circuit board designed and fabricated.

As it stands, from what can be seen here, the circuit board work done here was done with no regard to proper power and ground distribution. You could hack around with this messed up design for a long time and the likelihood of it being a reliable design are next to nil.

Take this as a learning experience of the kinds of things to NOT do in a design and set it aside. Start over and place big consideration on:

  1. Learn from others by taking a good hard look at the circuit boards in some name brand products.
  2. Learn about chip level bypass capacitors and why they are imperative.
  3. Learn about the need for plated through holes in a circuit board when there are multiple circuit layers.
  4. Learn why it is necessary to have a full ground plane in a design.
  5. Learn about techniques that are used in PCB design to allow for products to pass agency approvals for emissions and immunity. This is even important for one off private products that will never be sold because it leads to more robust and reliable circuits.
  6. Learn why you would want to hookup the power rails to the chips with traces that are more than the narrow ones used for signal hook ups.

Only after you have a reasonable mental grip on the above types of subjects is it appropriate to dive in and be making circuit boards. Otherwise you end up with a second or third mess like you have now.

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  • \$\begingroup\$ Can you maybe give me a suggestion about a book or something similar where I can learn these things? This is my first PCB I ever made, therefore I made surely several mistakes... \$\endgroup\$
    – arc_lupus
    Dec 6, 2014 at 19:15
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    \$\begingroup\$ I'm sure there are lots of books on various parts of this subject. I would be hard pressed to recommend any particular one. That said there is a lot to be learned from observation of existing products. Even to the extent of obtaining used network adapters, USB devices, wireless routers etc and ripping them open to look at their circuit boards. Surely there is some information to be gathered right at this site. As you embark on a new design ask questions along the way whilst showing what you are doing at each stage before (continued) \$\endgroup\$ Dec 6, 2014 at 19:22
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    \$\begingroup\$ (continued from above) you commit to it. There is a plethora of experience behind the folks that answer questions here that you can take advantage of. After all that is what this site is all about - if used correctly. \$\endgroup\$ Dec 6, 2014 at 19:24

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