2. Circuit Boards

For this step, you need to etch and populate some circuit boards. I’m not going to tell you the basics of etching or soldering, as there are already excellent guides out there for that. I will tell you, etching involves really nasty chemicals, which you need to handle carefully and dispose of properly. If that’s a problem for you, you’re better off paying someone to do this part for you.

If you do plan to do the etching yourself, I recommend checking out the following guides:

Vinyl-cut PCB Masking

Laser-rastered PCB Masking

Etching PCBs with Muriatic Acid

I tried both masking methods while I was doing this project and they both worked reasonably well. However, I did get better detail with vinyl and the laser method was ultimately more expensive and time-consuming for me.

Don’t attempt this part until you know how to do it safely. If you haven’t etched circuit boards before, I recommend at least finding a knowledgeable mentor who can help you through the process.

Step 1. Etching

  1. Clean your PCB blanks. I recommend sandpaper for this step. And get good enough sandpaper that you can sand them wet. That will allow you to avoid throwing copper dust in the air at this stage, as breathing it is bad for you. Wash them off when you’re done. The cleaned surface should be shiny and pink when you’re finished.
  2. Mask your PCB blanks. Once they’re masked, they’ll look something like this:
    Masked PCB Blank
  3. Etch your PCBs until all unmasked copper is gone. It isn’t really harmful for the boards for these projects to have a few little isolated islands of copper, but be sure all the traces have separated cleanly.
  4. Wash your PCBs. Inspect them carefully one last time for bridged traces.
  5. Store or dispose of your etchant properly.
  6. Remove the masking material.

Step 2. Prep Your Etched Boards for Components

  1. Rough-cut your individual circuit boards from each other. Several passes with a utility knife will work well enough for this. Be sure to always cut away from yourself and don’t cut on a surface you care about, as you will damage whatever surface you’re working on. You should now have something like this:
    Etched Hard Drive Power PCB
  2. Remove the masking material.
  3. Cut the edges of your individual circuit boards. Instructions are provided in each file explaining where to cut.
  4. Drill holes for your components that are appropriately sized and shaped. Compare to your components as you go, so you catch errors early. Your components may need holes of slightly different sizes/shapes than mine did, so I can only recommend that you plan carefully before you start drilling and cutting.

Step 3. Populate Your Circuit Boards

  1. For the four L-shaped boards, cut and strip 64 appropriate pieces of wire. Scrap wire from old PC power supply wires will do.
  2. Solder all components to your circuit boards. If unclear about orientation of components, refer to the pictures at the end of this step. Enough information is also provided in the file Step 2 – Circuit boards 2 – Hard Drive Power Boards v4.svg that you should be able to figure out how to wire your main power switch as well. Cut the male end from a fan extension cable and use it as the cable for the switch.
  3. Clean your circuit boards.
  4. Test all connections on your circuit boards, using appropriate test equipment. For dumb USB power ports, simply plugging in a rechargeable USB device to test for a power indicator will work. However, I don’t recommend plugging in anything expensive, in case you’ve somehow wired the power backwards.
    Hard Drive Power PCB Test
  5. Repair any faulty connections.
  6. If desired, lacquer the copper side of your circuit boards.

Your finished circuit boards should look like this (except the L-shaped boards may not have the buck converter modules attached yet):

Finished Circuit Board 1 Finished Circuit Board 2

Finished Circuit Board 3 Finished Circuit Board 4

Finished Circuit Board 5 Finished Circuit Board 6

1. What You Need 2. Circuit Boards 3. Power Cards

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