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Editor's
Note: CR4 would like to thank JScott13 for writing this story and sharing some
photographs of his DIY power supplies. Cheers, Scott!
Like
many DIYers, I build a number of different "gadgets" and solve a problem or two
from time to time. Still, it seems as though I spend a large percentage of my
time building power supplies. So let me share one example with you.
One
day, after ordering some power supply parts, I noticed my neighbor's VCR on the
tree belt. (For those who don't live in Massachusetts,
a "tree belt" is the grassy strip between the sidewalk and the street.) On
quick inspection, it became obvious that everything I needed was right there in
my neighbor's trash! Not wanting to wait - and intrigued by the possibilities -
I dug in.
I
built a very useful power supply and even cut up the VCR's case to make a nice enclosure
for the finished project. Since
then, I've built a number of power supplies from VCR parts, and they all work
like champs. I've also gained a smattering of VCR knowledge along the way. For
anyone who may want to follow in my footsteps, one important fact to consider
is this: VCR power supplies don't seem to fail all that often. After retrieving
dozens of VCRs, I have yet to find a bad supply.
I have a small example you can see here. In many cases, I
imagine you could just pull the old power supply out and use it "as is". In
this case, however, that would have made for a larger-sized supply - and I
needed something with a smaller profile. I was looking to power a few 9V guitar
effects. I hoped to build something that could sit on the ground alongside them
without getting in the way.
The transformer is a pricey bit of gear to scavenge, but the
trash is full of very nice examples. Tag sales are also great resources, so keep
your eyes open. Grab the bridge rectifier and the larger caps, too. I etched
two boards for the power supply in this photo. The one the transformer afforded was a
tidy, simplified connection to the remainder of the components. Of course,
perfboard could be used, but since these boards were easily produced on the
workbench, I opted for the etching.
It wasn't my intention to offer any electronic design notes
here, but if anyone would like the schematic for this simple power supply, just
let me know. In fact, aside from the transformer, the sheet metal that makes up
the VCR case is the next best part of the effort. I've always found the right-sized
enclosure for any project could take as long (or many times longer) to source-out
than building the project to that point.
First, I cut a piece of plywood for the base. I then sized
it to fit the two circuit boards nicely. That also gave me the remaining
dimensions for the box I needed to make. Next, I scored the VCR case and cut out the
parts with a Dremel Rotary tool (reinforced cutting wheels). There
are a number of ways to make these cuts, and this is only offered as one
possibility. Once cut to shape (in this case, a simple top and two-sided "C" shape
was all that was needed), I fashioned a Luan face plate. In it, I drilled holes
for various jacks, a switch etc.
This supply provides nine volts to both the pigtails and the
faceplate socket. Polarity is reversed on one pigtail.
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Re: DIY Power Supply
