* Third Installment *
** Build your own TV
**
Get ready for a little wood-working. Nothing really difficult
here, but something you and your friends will notice when looking at your set,
so try to do a nice job of it. Now you are going to build the cabinet.
Materials
you will need for this installment
* 3/8" plywood
* Threaded
bushings
* 2" x 1" Aluminum angle
* Misc small Aluminum
and wood materials
For this set, I suggest you use 3/8" plywood.
Go to a wood shop and buy a plywood with a nice cherry or mahogany veneer surface.
You might also go with 5 ply baltic birch. This is a very nice wood to work with.
Of course, if you have suitable materials around the house, use what you've got.
Many woodshops will cut the pieces for you, from your plan for a nominal charge.
So if you don't have a power saw of some sort, you might have the store do it.
Here
is the drawing for the materials you will need. There are five pieces of plywood
that make up the cabinet, plus a front and rear panel made from whatever material
you prefer. I used bakelite for the front panel and a length of aluminum angle
for the rear panel.
Make the wood parts first and
the front and rear panels later. I have included a number of photos in this installment,
many of which should prove useful later as you go along. Install the side panels
on the bottom first. You'll notice that the sides are a bit shorter than the bottom.
That is because the bottom extends past the front edge of the side panels about
a half an inch. This will make the front panel look more "dressy". When
you mount the side panels, use white glue and maybe some screws 
through the bottom, into the sides. Use a square where necessary
to be sure the sides are parallel and at right angles to the base.
The
top of the cabinet consists of two pieces, both of which can be easily removed
and reinstalled. You could just use wood screws here, but I prefer to use thumbscrews.
I epoxy in place, threaded #8 X 32 X 3/4" bushings for the thumbscrews to
screw into. Drill a hole in the edge of the side panel first, a little larger
than the bushing, coat the inside of the hole and the outside of the bushing with
epoxy and shove it into the hole. Use the epoxy sparingly so you don't end up
filling the threaded hole with the epoxy. It is a little extra work to do this,
but you'll be glad you did.
The rear edge of the rear top piece, lines
up with rear edges of the side panels. The front edge of the front top piece lines
up with the front edges of the side panels. When the two top pieces are properly
located, there is a space between the two tops. Guess what that's for. You're
right, it's clearance for the scanning disk. Sometime later you will be placing
the disc in the center of that space.
Now let's look at some pictures
. You are going to build this unit from these pictures. This
first photo is of a completed set, with the scanning disk removed. You can see
the four thumbscrews, two for the front top piece and two for the back. You might
also notice three black assemblies on the top surface. From left to right, they
are the bearing/pulley support for the scanning disk, then the motor (notice the
belt) and finally the LED array.There is one other item there in front of the
array, it's a support for a magnifying lens to enlarge the viewed image. The front
panel has a speaker opening (yes, there will be sound) and four controls. There
is a fifth lever knob that will not be included in this receiver. Also notice
that the bottom extends out past the front panel.
This next picture gives you a
better view of the three pieces just mentioned. Notice that these three assemblies
are mounted on the surface of the rear top piece. The bearing/pulley support is
in this case made of aluminum, the base being a short length of 3/4" angle
and the vertical section is a 4" X 3" X 1/8" thick piece of aluminum.
This support could be just as well made of wood. The motor is in a clamp made
of wood and cushioned with rubber. The magnifying lens support is held in place
by one of the thumbscrews holding the front top piece. More about these parts
in a future installment.
Here is another view of the top. Note that on
this receiver, the rear top piece is made from clear plexiglass, so that the internal
construction can be seen. On the left is the back side of the LED array, then
the motor and the bearing/pulley assembly.
And
another slightly different view.
And still
another view.
Here is a rear view of the receiver.
The rear panel has jacks for the video and sound signal inputs, the AC line cord,
a master Off/On power switch and some test points. There are also labels to indicate
the purpose of the various items on the back panel. This happens to be a 2"
X 1" X .060" aluminum angle for the rear panel. It has a painted finish.
The labels are computer generated on plain paper, covered on the front side with
clear Scotch tape, sprayed on the back side with Scotch #77 cement and stuck to
the panel. The front panel has similar labels for the controls. This gives the
set a more professional look.
This
view is looking directly at the front. The LED array on the right contains 24
LEDs. More about this in later installments.
Here is a view looking
down on the top.
And finally...
Here
is a closer view, looking down at the top. The electronics in this set are on
printed circuit boards, mounted in connectors. You can see some of those parts
in this picture.
If you have specific questions about the construction
up to this point, send me an Email.
End, Installment three
Peter
Yanczer
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