Page 5.
Page 5.

It's a good idea to use a little bit of paper masking tape and tape the two wires which you just soldered into place, together. That will keep them out of your way while you proceed.

Now lay out enough red and yellow wire to reach your hard drive connectors from the switch tabs. Solder the wires to the switch, one drive at the time. I also use masking tape on each pair to keep the wires together as shown in the picture below.

Now make your connections to the drive connector wires. Solder them and wrap each joint with electrical tape.

Now, beginning at the switch, bundle all three pair of wires and tape them together into one larger cable using masking tape. Stop bundling a few inches above the connectors. We'll call that the junction point.

You have to connect the ground wires from the power supply line and run them up to the junction point and out to the two drive connectors.

After you make the ground connections, solder them, wrap them with electrical tape, bundle them with the
other wires (as below). It's a good Idea to color your connector sockets and mark your switch so you know what drive is which switch position.
The finished product. It's not pretty but it works. Good luck!

This Web site is authored and maintained by Howard D. Dickens (Doug) and constructed using Web Studio. Copyright © 2007.

Before touching any electronic circuit boards, read the warning on Page 2.
January 17, 2007

Warning: before making this switching circuit, look at your hard drive while it is plugged into your power supply. See how the red wire is to the inside of the socket and the yellow wire is to the outside of the socket. The inside red wire is 5 Volts DC and the outside yellow wire is 12 Volts DC. The black wires are grounds.

Regardless of the color of the additional wires that you may use, if you swap the position of the 5 Volt and 12 Volt inputs to your hard drive, you will instantly destroy the hard drive when you turn the power on. That also applies to the black ground wires. If you swap a ground wire with either the 5 Volt or 12 Volt inputs to the hard drive you will instantly destroy your hard drive when you turn the power on.

It is best to check you new wires with a multimeter to make certain your wires connect the correct voltages to the hard drive before plugging the connector into the hard drive. If you get them wrong, your hard drive will instantly die when you turn the power on.