Computer Case "Power Strip" Project

[Lady Fitzgerald]

I've been working on and off (mostly off) on a computer case for far longer than I care to admit. After my dismal failure to build an SSD dock, I decided to tackle working on this sub-project next.

I designed this case with 14 (yes, 14) 5.25" bays for installing things like an optical drive, hot swap bays, data drive bays, front I/O panels, switches, etc. in an attempt to make it as modular as possible. This way, to add, remove, or move a component, I don't have to tear down the entire computer to modify the case. To make running power cables easier when adding, removing, or moving components, instead of connecting them directly to the PSU, I decided to make a power strip I could plug short jumper cables from the components into. The power strip has two sockets for each 5.25" bay.

My first attempt at a power strip was a failure because I made the mistake of encapsulating the components and, when I had a connector break inside a socket, there was no way to replace the socket. So, it was back to the drawing board. The new design will be completely serviceable but I'll go into the details of that later.

For now, I need a cable to go from four sockets on the PSU to the buss bars in the power strip (I'll go into more detail about the buss bars later). I had started the cable a while back but needed to make up one more wire set and plug all the wires into male connector bodies. That's what I worked on today.

First, I needed to crimp some pins onto some wires. These are some of the tools I used.

The tool with the red (orange?) handles is a crimper designed for crimping pins onto wires going into ATX power supply cable bodies. To the right of it is an automatic wire stripper. The parts box is where I keep many of the various pins I use for making computer cables.

These are the pins I used for this cable. One is ready to crimp onto a wire and the other two are already crimped to the wire.

This is what a properly crimped pin should look like.

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[Lady Fitzgerald]

The four #18 AWG wires with the freshly crimped pins need to merge into a single #12 wire (the larger size is reduce voltage drop). To do that, the four wires need to be crimped in a #10-#12 AWG butt splice sleeve. I've found it's a lot easier to crimp these when I tape the wires together with cellophane tape, then tape the bundle to the butt splice sleeve. Otherwise, I would need three or four hand to keep everything where they belonged while wielding the crimpers.

These are the crimpers I use. They actually compress the sleeve as well as staking it, which is much stronger than just merely staking the sleeve.

I found I get the best results if I insert the sleeve into the crimper with the seam of the sleeve facing down into the groove. This keeps the seam from opening up when squeezing the crimper. I also have found that the crimps both hold and look best if, after the first squeeze, I rotate the sleeve 180° in the crimper, squeeze it, rotate the sleeve 90° and squeeze, then rotate another 180°and squeeze. This squares up the crimp, which looks better and tightens up the crimp, and puts the staking on all four sides.

The little dings you see on the insulation don't go through to the wire and will get covered with a heat shrink sleeve so they aren't a problem.

[Lady Fitzgerald]

Here, the #12 wire has been crimped into the sleeve.

Now it's time to shrink a heat shrink sleeve onto the butt splice sleeve. Here, the heat shrink sleeve has been cut to size and slipped over the butt splice sleeve.

I bought this little heat gun a few years ago specifically for shrinking heat shrink sleeves. It's the ideal size for the job.

[Lady Fitzgerald]

Here, the heat shrink sleeve has been shrunk.

Now, the pins on the wires went into the connector bodies with the rest of the wires.

That looks like an electrician's nightmare, doesn't it? Here is the little hole the connectors will have to pass through on their way to the PSU. I've already tried it with five wires in each connector. It's "fun" but doable.

[Lady Fitzgerald]

This is a shot of the PSU where the cable will get plugged into.

Scary looking, isn't it?

Here is a view of the entire compartment the PSU and excess wiring are stuffed into. The compartment has a cover plate that tidies things up a bit.

This is an old Radio Shack Micronta digital multimeter. It was one of the first one to come out. I've had it almost 50 years and it still works just fine.

I'm going to be using it to make sure I plugged the pins into the correct holes.

[Lady Fitzgerald]

Trying to hold two probes and two places to put the probes can be a bit of a juggling act so I made adapters to go over the end of a probe that will fit into whatever socket I'm pin I'm checking. The female pins for "Molex" four pin power connectors fit perfectly over a probe so I just crimped one of those onto a pin I needed to fit into a connector.

This allows me to poke the pin on the probe into a connector, freeing my hands for connecting the other probe to the wire to check for continuity.

I'm happy (more like ecstatic) to report everything checked out. I love it when a plan comes together.

[Lady Fitzgerald]

I tried posting this last night but the forum went down and I couldn't get back on for 14 hours.

This is the outlet tester I bought recently. I already had one but it only checked for miswiring. This one also checks for voltage. I was able to use it to verify my almost 50 year old multimeter was still accurate to three figures. I wasn't real thrilled about this tester though. The battery compartment cover is secured with a screw, making battery replacement a bit more inconvenient. The real killer was the ground pin and hot and neutral blades were too thick. The first time I plugged it into an outlet, I was afraid I was going to break the outlet before I got it out. I had to sand down the pin a little and file the snot out of the blades. it's still a bit tight but, now, it doesn't take two men and a boy to pull it out.

[Lady Fitzgerald]

When I first got the idea for making a power strip for inside the computer case, I made a rough mockup for a proof of concept of sorts.

The plastic "case" is a wire mold for running low voltage audiro, etc. cables on the surface of a wall. The connector on top is a punch down type, inline SATA power connector. The "wires" are strips of copper I cut to make a buss to connect multiple connectors. The wire mold came with a foam adhesive strip to fasten it to a wall, etc. so I stuck a piece of it to a scrap block of aluminum and stuck the base of the wire mold segment to it.

This time around, I'm making this power strip serviceable. Replacing a connector in it will be a royal PITA but, at least, it will be doable.

[Lady Fitzgerald]

These are some of the parts going into making the power strip.

I had already started modifying the wire mold to take the power connectors. I had to cut a gazillion (give or take a bazillion...OK, there are twenty) slots in what is going to be the top face of the power strip for the power connectors to poke through (it's actually the bottom of the wire mold but the connectors fit better through the bottom than the top). After capping the ends and painting the "top", I poked the connectors into the slots. This better shows the connectors poking through.

This is what the connectors look like on the flip side.

What looks like dirt or black mold is actually overspray from when I painted the outside.

[Lady Fitzgerald]

I got a bit ahead of myself and kept on working before remembering to take pictures. Sorry!

This is the cable that will go from the PSU to the buss bars in the power strip.

I've already attached the connector bodies to the pinned wires, then assembled it all into a single cable with four branches splitting off at the PSU end. I've already slipped some sleeving over the wires and secured it on one end with a heat shrink sleeve. To make working on the end of the wires that will be soldered to the buss bars easier, I slipped an unshrunk (is that a word?) heat shrink sleeve over the sleeving, then scrunched up the sleeving and temporarily secured it with a strip of gaffers' tape to keep it all out of my way and out of harm's reach.

Earlier, I mentioned I had made some pin adapters to go onto the end of my multimeter probes. This is another one I made. Even with a fine tipped adapter on the end of a probe, checking voltages in a female SATA power socket is pretty much impossible because of how they are made. Instead, I took a male connector with wires attached and put a pin for four pin "Molex" connectors on each wire. Now, I can plug in the cable into a female connector and easily attach the end of a probe to as wire on the male connector. This made routing and test the power strip umpteen times easier, even though it's still a bear.

[Lady Fitzgerald]

Again, I got ahead of myself and failed to take pictures. Again, sorry!

There isn't a lot of room between buss bars for attaching wires. I had thought of stripping the end of the wire, fanning out the strands, the soldering them to the face of the buss bar but depending on solder only is not a very good idea. There should always be at least a decent mechanical connection. What I eventually hit upon was to drill a small hole in each buss bar, poke a wire into each hole and bend it over, flatten the strands with pliers, then solder it. That worked fairly well.

Since the copper of the buss bars would conduct heat away from the joint too fast for a soldering iron or gun to be able to get the joint hot enough, I used my cute little Dremel butane torch. After cleaning the copper with a strip of red ScotchBrite, I poke the wire in the hole, bent and flattened it, applied paste flux to the wire strands and the buss bar, then used the torch to heat the buss bar, aiming the flame alongside where the wire was, then, when the wire and bar got hot enough, applied the solder. After letting the bar cool down for a while(for some funny reason, it got quite toasty), I moved on to the next wire/buss bar. Juggling all that was...ah... interesting and fun (lied Jeannie through her teeth).

Just about when I was ready to start on the third buss bar, it dawned on me that I had put the wires on in the wrong direction (mutter, mutter, mumble mumble). After scratching my head and not exactly muttering some of those words Mama told me not to use, I decided that, even though doing so was going to be a royal PITA, repinning the connectors at the other end of the cable would be much easier than trying to redo the soldering.

Repinning the connectors was so much fun (and I believe in the Easter Bunny). Removing the pins from the connector bodies was the most challenging part. I have a couple of tools that are designed for removing this kind of pin but they can still be a bear (think grizzly on steroids in a really bad mood) to remove. The sad fact is they can't always be removed. However, I got lucky this time. Most of the pins weren't too bad to get out except for a couple that gave me fits (and had me throwing a couple of fits). Still, I was able to get them all out without having to cut wires and toss connector bodies. I spent almost an hour on removing twenty pins.

Tracing the wires and reinserting the pins wasn't difficult but it was seriously tedious and time consuming. This time, I spent a full hour. What didn't help was inserting two pins in the wrong holes and having to remove and reinsert them. So much fun.

Rather than trying to use pin-out charts (and probably screwing up big time), I used a factory cable, my multimeter, and the test cable I showed earlier to determine which pin should go into which hole. While tedious, it was fool proof. The procedure even caught my two mistakes.

For cheap insurance, I spent another half hour or so checking the connections for correct placement and shorts. I found a couple of pins I hadn't inserted deeply enough and were ready to fall out (easy fix, shove harder) but, otherwise, everything checked out.

[Lady Fitzgerald]

Here is where I finally got the buss bars installed. I've found when filling the slots in the punch down connectors, it's best to fill the outside and middle slots first, then fill the remaining ones. This avoids having the last slot on the outside closing up if going from one side across to the other. In theory, it's simple to install the buss bars. Just start tapping with a small ball peen hammer on one end and gradually work down to the other end. In real life, it's like herding cats. Still, I got there.

This is what it looks like from above.

To make sure I didn't get any shorts between the buss bars where the wires are soldered in, I taped the wires where they meet the buss bars to replace insulation that melted off. I had planned on using heat shrink tubing but heat from soldering ran up the wires and prematurely shrank them. Even though I had staggered the holes to make it less like the solder joints would contact each other, I played it safe and taped the sides of the buss bars. It looks like heck but should be problem free.

After covering some of the mess with another layer of tape, I stretched the sleeving back out and shrank the shrink sleeve.

After that, I fed the cable through a hole in the bottom cover (getting those connectors through the hole was "fun"), then snapped it onto the top portion (I had to use grooved joint pliers with the jaws cushioned with tape to get the joints to close and latch).

The next step will be to put some foam mounting tape on the back, then install it in the computer case. I'll go into more detail when I get around to doing it in a day or two.

[HaveaMint]

I have to admit I didn't read everything, but from my years in electronic repair I prefer to eliminate any possibility of a future connection failure of any permanent connection to be soldiered and not crimped.

[Lady Fitzgerald]

I have to admit I didn't read everything, but from my years in electronic repair I prefer to eliminate any possibility of a future connection failure of any permanent connection to be soldiered and not crimped.

The pins are the contacts in connectors that plug into the PSU.

I'll grant you that crimping pins to wire is pretty much an art. It does require a certain amount of skill. I've crimped hundreds of pins over the past couple of decades and had a lot of failures before I worked out the correct combination of pins, tools, and technique. I also do a pull test on pins I've crimped to make sure I didn't make a bad crimp, which I almost never do anymore and I usually can see a bad crimp. Usually it's the insulation wings crimping crooked. Usually, those bad crimps can survive the pull test but I don't trust them and replace them anyway.

Maybe I confused you when I said I had a couple of pins pull out. I was referring to the pins pulling out of the connector body because I hadn't pushed them in far enough for the prongs that hold the pins in the connector body to properly seat, not because the pins pulled off the wire (it was pretty crowded there).

There have been times when I needed to crimp pins onto wire that was larger than the pins were designed to be used with (the larger wire was to reduce voltage drop, not carry more current). Those I did solder after crimping to make sure they held. Soldering pins is a delicate operation because there can't be any solder build up on the pin or it won't fit into the connector body. It's also very easy to melt the insulation where the pins insulation wings are crimped to the wire's insulation (that part acts as a strain relief.

I don't know if you read the part where I did solder wires onto the buss bars since those could be a permanent connection as well as because there wasn't enough room for using connectors.

Here is a picture of one side of a test connection I made to see if this way of connecting a wire to a buss bar would work. I didn't bother to solder it in the test since I trust my soldering skills.

This is what it looks like on the other side.

It's hard to see in the pictures but, when looked at from the end of the small section of buss bar, the flattened wire strands and buss bar aren't much thicker than the wire where it's still insulated. When properly soldered, very little more thickness is added.

[Marie SWE]

one more project I see.

I was thinking of Apple and Mac when I saw all cables in black.

[Lady Fitzgerald]

one more project I see.

I was thinking of Apple and Mac when I saw all cables in black.

Ack! Me? Emulating Apple and Mac? What a horrible thought!

I like black cables because they blend into the background better, both when they are internal cables or external ones that are easily seen

[Marie SWE]

one more project I see.

I was thinking of Apple and Mac when I saw all cables in black.

Ack! Me? Emulating Apple and Mac? What a horrible thought!

I like black cables because they blend into the background better, both when they are internal cables or external ones that are easily seen

yes, you. Here is a picture of the horror.

[Lady Fitzgerald]

one more project I see.

I was thinking of Apple and Mac when I saw all cables in black.

Ack! Me? Emulating Apple and Mac? What a horrible thought!

I like black cables because they blend into the background better, both when they are internal cables or external ones that are easily seen

yes, you. Here is a picture of the horror.

Nah! My PSU is a dark charcoal gray. Besides, black goes with everything. It also makes computers and cables faster, much like stickers.

[MurphCID]

I am always in awe of your technical prowess. Just amazing.

[Marie SWE]

Nah! My PSU is a dark charcoal gray. Besides, black goes with everything. It also makes computers and cables faster, much like stickers.

I can always make the PSU dark in GIMP if you want.

I love to follow your your project threads. Keep it up, looking good