Today I will be discussing the assembly of my newly constructed variable power supply, the C6724 by Chaney Electronics purchased from the site Electronic Goldmine. This device connects to a normal AC power outlet and steps down the typical 120 volts AC from the power outlet to safe levels that can be manually set anywhere between 0-12 volts DC. My main purpose for building this unit is to power analog audio effects that I have been wanting to try out using breadboard prototyping, which you should keep an eye out for in future posts.

1 assembly

If you are already somewhat familiar with the art of soldering, installing components correctly, and perhaps some fundamentals of electronics, assembling this unit will be a breeze. Since all basic parts and detailed instructions are included, you really only need your own soldering station with the appropriate soldering accessories (I ordered mine from Circuit Specialists), standard wire stripper/clipper tools, a phillips head screwdriver, and perhaps some kind of “helping hand” device to keep the circuit in place while you put it all together. Difficulty was rated 2/5 and I’d say that is a valid assessment of the challenge in building this power supply.

2 testing

The kit comes with a PCB, two 220μF 35V electrolytic capacitors, four 1N4003 diodes, a pigtail fuse, red LED, 1KΩ potentiometer, an NPN TO220 power transistor, heatsink for the transistor, 6.2KΩ resistor, 100Ω resistor, 4.7KΩ resistor, an on/off slide switch, the power transformer, stranded hookup wire, standard electrical cord, along with some nuts and bolts. All of the component values were accurate according to the measurements made with my multimeter. Along with the parts, it comes with fairly thorough assembly instructions, schematic, diagram of the unit/parts, troubleshooting hints, and a detailed theory of operation. All-in-all, a well thought out kit.

3 testing breadboard

In my opinion, the most important steps would have to be orienting the capacitor leads correctly, installing the heatsink onto the transistor using a screw without damaging the component, the red LED cathode lead orientation, the four diode’s cathode leads orientation, installing the fuse without damaging it, and measuring the right lengths of wire to cut. Such crucial steps are also highlighted in the instructions and diagrams provided within the documentation. You also want to make sure not to heat any of the components too much while soldering to avoid damaging them in the process. Some excess leads were also clipped off after soldering was done.

4 testing multimeter

After assembly, it did not surprise me that the unit did not turn on at first. I had done everything exactly as the instructions described, however the switch was not labeled to show which side was on/off, so it turned out that the connections to the lugs on the switch had to be reversed. After doing this, I was pleased to see the red LED came on for the first time and correct voltage values were measured by my multimeter! The +/- leads for the power supply were connected to my prototyping breadboard and successfully sent power through it, so I knew that this was now becoming an exciting and worthwhile venture.

5 enclosure

Suddenly not feeling very safe testing a power supply without any type of outer casing, I immediately took it upon myself to find an enclosure that would house this unit safely. Upon receiving the plastic enclosure, I thought out exactly how it should be implemented, such as placement of the potentiometer, switch, LED, and power wires, before finalizing the circuit placement within the enclosure using a hot glue gun. Have some sympathy with the results, as this was my first plastic enclosure build.

7 drilling

I began drilling holes into the plastic enclosure for the corresponding parts. The potentiometer and output power leads had standard drill bits, but for the switch and input power cord I had to first carefully measure the size of each and etched these proportions into the plastic with an x-acto tool before drilling small holes that were enlarged manually with a reaming tool.

6 reaming

Being very careful not to weaken or crack the plastic, I slowly expanded these dimensions until the related components fit into them just right. The on/off switch was a particular challenge in this regard, as the connecting wire I used for it was a bit shorter than I should have originally attached. However, after some struggle pulling it through the hole I did manage to get it installed properly.

8 enclosure top

During assembly, I did not realize that the red LED light could have been extended upward with wire so as to fit directly into the top LED hole on the enclosure, but I drilled a sight hole for it regardless. You cannot see when the LED is on from an angle at all really. At least looking straight down from above the red light is visible, which is useful to ensure that the power supply is turned on.

10 enclosure back

Once completed inside the enclosure, I was very satisfied with the result. However, something was still missing…

9 enclosure front

Ah, yes! No building project is complete without some nice aesthetic ornamentation. Here I decided to use an Obey Giant sticker with a hole in the mouth just big enough to let the LED shine through. The level of swag is now incomprehensible…

11 enclosure finished

That’s all for today. Be sure to like my Facebook page and follow me on Twitter for the latest updates! Check back soon for some upcoming projects using this power supply that will hopefully blow your mind.