128 Pin Connector

Working on building a 128 pin connector for a 16 foot cable for aircraft hook-up to a SATCOM wireless router.

 

Got some pics!

I have already inserted 5 shielded cables with 4 conductors each. Counting the shielding pins that makes 25 pins. I'm halfway done with the insertion of 6 shielded cables with 3 conductors in each wire. All together I have completed 37 pins out of 49. After this is done I move on to the single conductor, unshielded cables. I think I have about 14 of them to do.

All-in-all things are looking good. I have a nice stagger on my shield splices and the tension on the shortest wire is minimal. I cut it closed to having the shortest of the shield splices too close to the cannon plug's strain relief but it looks like it'll be okay. The plastic goes into the relief but not the solder so things are up to spec.

They'll be more pictures as I progress. I am eventually going to have to make two or more of these cables but the stock for my 3 conductor shielded wire is only going to allow me to make one of them. Once I get more of the wire in I'll have 2 or more of these cables built up.

What makes this project slow going is the fact that I have to document everything. I mean the shield spices I use, what pins I choose for the shielding of each wire, the length of each wire strip, as well as the order of insertion I find the easiest to accomplish. This is all to be able to make production procedures when this product gets released.

37 Pins already placed:


24 Pins to be connected up:


12 More pins to go:

 

Thanks for the input CocaCola. In the end the entire cable will need to be shielded so I think the heat shrink might not be needed. If I do use it for anything it would only be at the ends where the strain relief is.

I took some more pictures. I finished the last of the three conductor wire and on Monday I'll be doing the 14 single conductor wires. I added a piece (sample) of possible shielding options. This mesh has carbon all over put there by using some sort of electric method. They had a little video from the site that showed a piece of this stuff with lighting bolts traveling across it's surface. While it did it was imbedding or implanting or impregnating, or whatever you want to call it, carbon on the surface of the mesh. I don't think this will provide enough shielding though. The engineers might go with something metal. When I try to ohm this stuff out I get just about 900 Ω. We will remeasure after the cable is built up and might order a full length of this stuff for testing.

Here's the pics and I'll be posting more pics on Monday with the 14 single conductor wires set in place.

All done!


Shielding sample


Another angle with shielding sample


The full cable and all it's glory


& just for fun here is a pic of where I do most of my work at

 

Here's four pictures of the cable by lunch time.









I'll post of what I finished today.

 

One more of the whole thing.

 

Okay, I'm done! Now I have the tedious task of checking every pin for a few things. One, I have to make sure they are all locked into the cannon connector. Two, I have to ohm out every pin to it's corresponding wire on the other end of the cable. Three, I have to check every pin to the shielding to make sure all my splices are okay. And ideally four, I have to check every pin to every other pin to make sure there are no shorts. I think I'll skip that last check as I don't see any reason to check for that since the only way these would short out is through the shield splice and I'm already checking for that.

I have another cable for the same product that I'll be building up next. This cable will stay naked until the engineers decided on a whole cable shielding method/material.

 

I have good news and bad news.

The good news is everything ohms our correctly.


The bad news is that I forgot to place 13 black wires. I didn't even notice I was missing my first sheet of pin outs until I started to verify everything. Oh well, should be simple enough to do I think. I'll have to take care of it tomorrow as it is quitting time for me.

 

I have finished the first cable and I am starting on the second one. I'll be using the same black wire and the four conductor but instead of the 3 conductor wires I'll be using ten lengths of twisted pairs (two conductor wire with shield). I have all my environmental splices in place (the blue things) and tomorrow I will begin to add the pins. I have cool pictures of everything but it is 12 minutes past five o'clock and I want to get home. I'll post the pics either later tonight or tomorrow when I get back to work.... most likely it will be tomorrow as I have to put all my documentation from that first cable into a readable format. In other words my notes are messy and unorganized to anyone other than myself and the engineers need the info so the design can be written up. See you all tomorrow.

 

Updated pictures:

This is the first cable with the rest of the black wires in place that I forgot originally.


This is the first cable in all it's naked glory. As mentioned before the engineers still have to decide how they will dress this thing up. Options are carbon plated nylon mesh or full metal braid with thick full length plastic/rubber type of heat shrink or preformed tubing.


These next two pictures are of the second cable with the solder splices in place for the shielding. I haven't gotten all of the 4 conductor wire done as we are out of stock but should be getting more in soon. Also the twisted pairs (the two conductor wire) is 1/2 way done. You can see the other six strands still laying on the table.


Can anyone see my mistake I made on the solder splice spacing? The first 4 conductor wire in the pic (the one on top) is slightly off. It's just a bit too far back but it's okay as I will be adding more of this wire when we get it in stock and I will use one strand to fill in the gap.

The whole idea behind placing the solder splices just a bit off from the previous one is to make sure they don't build up and become very thick at that point and in the end would cause strain on all the splices. This is actually a process indicator defined by IPC-A-620A when daisy chaining shields together. Even though I'm not daisy chaining these together it is still a good idea to stagger the splices when a lot of them are in one cable. In my case each shield will have it's own dedicated pin on the connector.

This last picture is of the first cable coiled nicely on the floor of the lab and the loose end of the second cable with all it's strands in disarray. Not to worry though, I'll have everything put together nicely once the connector is finished.


P.S. I like this way of attaching pictures (attach & link). The only bad part is the resizing I have to do. It's just another step in the process of making my logs on here.

Thanks for taking the time to read all this.

 

It's 15 after 5 and I need to go home. I'll post pics of everything tomorrow. Basically I have finished all the pins. Now I just have to insert them and do the single conductor wires.

 

Picture Update

This is all the solder splices in place on the two conductor wires.


This is all the two conductor wire with pins.


And the 4 conductor wire with pins.


Sorry for the blur but I was in a rush last night. This is the wires on the other end in a little bit of a chaotic jumble.


I'll be adding pics of the 4 conductor wires in place, the twisted pairs in place, and then the hook-up wire (unshielded one conductor wire) with pins and then after they are in place. I plan on having this finished today. Tomorrow I begin work on the LED circuit. I'll be soldering everything to a small PCB but first I'll be using a breadboard. The circuit is going to be using an ALD4501 IC. It's basically a dual 555 chip. You can see the data sheet by clicking on the link.

 

Thank God for these logs. I am starting the next phase of my project that requires me to read back through my notes on these two cables and I can't make sense of anything. I could have spend a good 1 or so hours remembering or interpreting them but I just came here. Found what I needed so quickly I thought I spend a bit of the surplus of time I just saved posting this little note.

Anyway, as I said above, I am beginning the next part of my project. The item these two cables hook up to needs to be tested and have software developed for it. This requires some sort of test fixture. The test fixture will allow access to all the pins while the item is being powered. This will help in both software development and testing that is required from the FAA as this item is for an aircraft. You might look back at my other posted about DO-160 testing. I will entitle this log "Test Set/Test Fixture" as I will not only be developing the test fixture but all the good stuff that goes with it such as these cables. In this new log I will also go over what I will be attaching to the other end of these cables.... don't worry, nothing so complicated as these double density connectors.

I hope you enjoy.