Soldering below an adapter

Question

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:

Answer 1

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.

Answer 2

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.