Intro: PowerBox: Recycled AC Power Distribution System From Old Computer AC Controller
Most AC powerstrips do not have good filtering and do not have individually switched AC sockets. I had been on the lookout for a better solution and fortunately found a discarded computer AC controller that I converted to a well filtered and individually switched power controller. My repackaged version was built over two days, has a smaller footprint and is turning out to be heavily used.
These old AC controllers were placed under a heavy CRT monitor and your desktop computer, monitor, rinter, etc were plugged into the controller and you would then be able to switch stuff on and off. Ah! the good old days.
CAUTION: This is live AC so there is significant risk of blowing the fuse in your house, killing expensive equipment or hurtung yourself if you screw up.
Step 1: Parts From a Dumpster ...
While throwing away trash at a dumpster I found a switched AC power controller that was used under CRT monitors. It was built quite well so thought would bring it home and at least get a few parts out of it. Looked online and found that patents had been issued for this device - a "Computer Accessories - Power Director". Good specs (see label) including the ability to individually switch each AC outlet and LED indication to show the power is on.
Plugged it in and it was dead. So opened up the case and removed the parts. The steel case was also worth saving for some future lab device.
While taking apart the electronics, discovered that the neutral wire had come off the main filter board (with the copper coils), so this could be brought back from the dead by resoldering the neutral wire. Decided to make a different form factor of the the AC power controller. As I wanted to limit the size of my device to 6 inches I had to cut the PCBs which hold the switches and the LEDs into half. The photo shows the PCs after they were cut.
Step 2: Laying Out the Parts and Wiring the AC Sockets
Most of my DIY equipment is 6 inches tall so started up mocking up the device in a drawing program. First, tried to fit the parts in a 6 x 3 x 6 inch box it would not so had to expand the size of my concept to 6 x 6 x 6 inches. The 6 inch limitation means that I had to cut the long circuit boards that held the switches and LEDs into half. I looked at possible locations to cut the board (minimum number of traces) and cut these on my bandsaw. I would connect the traces later with wire.
In the original PowerDirector, there were 5 controlled sockets and a hidden internal socket that was controlled by the Master switch. I decided to bring the Master socket out to the front panel.
Once I was happy with the overall parts placements in my drawings I drew the measurements on a 6 x 6 inch piece of white Pergo laminate flooring and cut out the holes with a drill and a dremel. On checking I found that I had screwed up the holes for the switches and LEDs so had to redrill these and fill-up the wrong holes.
Started populating the parts. Placed the AC IEC sockets and then the two sets of PCB for the switch and LEDs. The wiring diagram shows the electrical connections. The live wire from an IEC male socket (at the back of the enclosure) would connect to the re-settable fuse and then to the filter board. The filter board also had two wires - one for neutral and the other for ground. The output of the filter board had three wires; a black wire for filtered LIVE AC that went to the Master switch; a wire for filtered neutral and a thin wire for the LED commons. The other switches were switched on by the Master switch.
The black Live wires from the switches were trimmed and then pushed into the corresponding slots of the IEC sockets. I had not used these "push" sockets before. Pushing the wire results in the insulation being cut by the metal pin inside the socket and the exposed wire making good electrical contact with the pin. Once the switched Live wires were inserted, I used a long piece of black wire remaining from the trimming operation and inserted these into the earth pins. A separate wire was inserted into the neutral pins of the sockets. The wiring was repeated for the other side. A loop was introduced into the Earth and Neutral wires so that I could connect the two sides as well as connect to the filter board.
The IEC sockets from the PowerDirector came with caps which were then re-installed.
Checked the wiring out with an ohmmeter. It looked good.
Step 3: Connecting AC Input to Fuse, Filter Board and Switched AC Sockets
Holes were drilled into the copper traces on the switch boards and black wires were soldered to connect the traces of the two boards. The two sets of AC sockets (left and right) were connected by solid wire (white). Small regions of insulation were scraped off from the loops of the black wires from the sockets and the white wire was soldered to these loops. The white bridge wires were then soldered to the Live and Neutral outputs of the filter board.
The thin white LED wires from the LED boards were soldered (through a blue extension wire) to the corresponding thin white wire on the filter board.
From the input IEC socket in the back ...
- Earth wire to the filter board and to the white bridge wire connecting the Earths of the switched IEC sockets
- Live wire to the resettable fuse (brown)
- Neutral wire to the filter board
The red wire but ties three black wires together. One will connect to the resettable fuse in the front and two connect to the filter board (labeled "Live" in and "CPC"). All wires were soldered and some were then covered with the plastic wire nuts. All exposed connections were taped with electrical tape.
Step 4: Putting the Enclosure Together
The two L-shaped pieces were glued together (with an excess of clamp). Used polyurethane based construction adhesive. Hot glue was applied to the IEC sockets and around the LEDs to fill in gaps in my less than perfect cut holes. Pilot holes were drilled to hold the side panels. And then nails were tapped into these holes (did not have the right sized screws). The unit was ready for painting.
Step 5: Finishing
Two coats of black acrylic paint were applied and then the unit was placed into use.
I went the lazy route and hand drew the labels on the PowerBox instead of printing, gluing and varnishing the final labels.
Placed the system on the shelf of my electronics workbench ready to switch life into other instruments.
(The box to the left of the PowerBox in the last picture is a second version of an ATX derived lab power supply under construction - this one will have two adjustable PSU's - 0-12V and 12-50V at about 5A each - in addition to the fixed 3.3, 5 and 12V supplies.)