I was at my local thrift store a few months ago and saw this radio, its case was not in too bad a shape, but when plugged in nothing happened. I talked them down to 35 bucks, and loaded it up. When I got it home and took the frame out of it, it was apparent that it had been on fire, and that most of the point to point soldered electronics were cooked. I then researched how much a fully functional one would be and perfect ones go for about 300.00 bucks.
So I decided to modernize it, but keep the old look, and make the old controls work a new radio. It needed a full make over and a revamp of everything. The original parts are the knobs, case, metal frame, dial and bezel.
After its conversion its an AM/FM radio with MP3 player, with Bose bookshelf speakers and 150 watts of power.
This instructable cannot cover all radio conversions for all models of radio's, but is a good starting point, its also a complicated build requiring you to think on your feet and come up with your own solutions, I will give you all the information I can.
On to parts and supplies:
Step 1: Tools, Parts and Supplies needed
drill with bits
sanding equipment (orbital sander recommended)
Replacement AM/FM receiver (KLOSS model 1 used here)
Small Mono or Stereo amplifier (Pyle 160 watt used here)
Speaker(s) (Bose bookshelf speakers used here)
scrap particle board 3/4" thick
sand paper (if your case is in good shape, 400 grit to 1000 grit)
Lexan sheet plastic (available at most hobby shops in 8x10 sheets)
paint (some cases including mine had black or gold trim)
1/8" plywood to make cabinet back or paneling.
Knowledge of electronics, woodworking, and mechanical skills needed for this conversion.
Step 2: The Radio Before and the dismemberment.
I started by stripping the case of all hardware:
If you don't know how these radios are put together its pretty simple, all the major electronics are mounted on a heavy metal frame that is easily removed to service and change the vacuum tubes.
Its common for many of these radio's to have the frame bolted to a shelf with thumbscrews, thats how this one was, but to pull the frame out you will need to remove the knobs with a flat head screw driver.
Step 3: Pulling the frame and stripping the rest of the hardware.
I recouped some of my money for this project in selling the spare parts online.
The large metal frame was stripped of all parts except the large dial and its tuning mechanism. I removed all the parts above and below the frame.
Later this frame will be used to support the new radio and its equipment.
Step 4: Refinishing the Cabinet
Because this cabinet was in decent shape, having only a gummy varnish on it, I used an orbital sander and 400 grit to remove the top layer, then the 600 grit to smooth it followed by 1000 by hand to make it silky smooth.
Be very careful and don't sand to much, almost all of the cabinets are made of plywood veneered in thin exotic wood.
I then stained the top center and bottom to simulate the use of different wood as trim.
Then the edge banding was repainted black just like the original, follow this with your favorite finish, I use spray on polyurethane, several coats with light sanding in-between coats.
Your case could need more or less work than mine, or you may want to leave it completely alone and have a very rustic looking radio thats up to date inside.
Step 5: Grill cloth replacement or cleaning?
I also put the Bose emblem from my speakers on it just for effect.
Should yours need replacement, many places on the internet sell suitable cloth, I have even seen that older semi transparent curtain cloth that would work.
In this picture you can also notice the stained trim.
Step 6: Speaker installation
I removed the mount, made of plywood and enlarged the hole so that two speakers siting on a shelf behind the hole could fire out of the enlarged hole.
I will be using a stereo amp so both speakers will be used. You can just use one if you want to go that route.
I had an older set of Bose bookshelf speakers in my closet, most any type of speakers could be used, you just need to match them to your amplifier, you could also use a good set of computer speakers...
I started by making a particle board shelf for the speakers and attaching them to this shelf with wood screws. I also put felt between them to ensure that they didnt rattle.
This was mounted in the base (see the second picture) using wood screws.
Step 7: Display cover replacement.
A little research and I found several sites that offered to sell you a kit to let you make a replacement.
I however made my own using sheet lexan and my oven. Here is the step by step method I used to make a plug or mold for my display:
Wile your at the hobby store getting your sheet of lexan pick up some 3/4inch thick balsa wood. ( if you cant find it then glue some up to that thickness)
Use the original metal bezel ( the part that held the original dial cover) as a guide and trace the inside outline on your balsa and cut it out.
Test fit your balsa plug and make it fit a little loose by sanding it down.
Then round over all the edges like your original, make sure you don't have any sharp edges or dents as they will show up in your new dial cover. The plug should not fit tightly into your bezel, it should have a 1/32nd inch gap all around the edge.
Now peel the anti-sctratch coating off of the lexan and lay it over the the balsa mold/plug, you want at least 2 inches of overhang around the mold. the sheet of lexan you bought will yield two or three usable pieces, and if your like me, I messed up the first one.
Put the mold with the lexan on it, on a cookie sheet and put it into the oven at 300 deg, leave the door cracked and watch as the lexan starts to droop over the mold. This wont take long!
When you see it droop down to the cookie sheet, wearing some oven mitts, quickly remove it, sit it on the stove and push the metal bezel down over the mold and hold it there until it cools.
You now have a new plastic dial cover to trim out and use!
Step 8: Radio Receiver and Amplifier Selection
I settled on the Kloss model one radio, it has an excellent receiver and has an optional input I could use for MP3 or other inputs. I found a good used one online, you may choose a different radio and you will have to engineer your own connections for it.
I wanted a good amount of power as well, I looked around for a small amplifier to mount on the frame with the radio, I settled on a small sized Pyle PRO style amplifier, they are small and seem to work well, I have used one for a couple of years and its been good.
You could also use a good set of computer speakers and eliminate the amplifier as long as you can get the volume control to the front.
Step 9: Mounting the Radio and amplifier
The amplifier was not that difficult, Its only challenge was removing the USB port from it and extending it to the back of the radio, this was done so I could easily reach the MP3 controls and change the USB drive anytime I wanted.
I wont go into to much details on how it was mounted and wired, this is just to give you an idea of hows it can be done, the chances of you finding the same radio that I used as very slim, so you will have to do allot of custom work, just like I did, I will label each picture with as much information as possible.
To extend the controls, some were rewired and extended, and some were left in place and driven with a belt from the old controls using RC car belts and pulleys. The hobby shop was a good resource for this project.
After wiring the components and testing everything for good operation I epoxied all the wiring down to keep it from vibrating.
Only do this after you know everything works fine.
Step 10: Knobs and control mounts
As you can see from the pictures I ran belts from the stock knob controls to the new radio's controls. These were toothed belts used in printers and RC cars. The pulleys were from RC cars. Very strong but cheap.
The station indicator needle uses a string wrapped around the tuning knob shaft, I kept this arrangement, its just for looks but moves when you turn the dial. Its kept tight by a spring in the loop. This was the factory setup, but with a new fishing line string added.
A good way to run your belts is to get them a little longer for your pulleys, and use a plastic stand off bolted to the metal frame for a belt tensioner. Some of the knobs on the Kloss radio were also sanded to ruff them up so the bets would gain traction.
Step 11: MP3/USB drive port and radio back
Its mounted low enough that you don't notice it when its running.
The stock radio didn't have a back board covering the electronics, the old stuff had tubes, and tubes were very hot.
This one doesn't get very hot, so I made a dust cover with a few vent holes. Its made from 1/8" paneling painted black with a undercoat paint, this is a rubbery paint that helps it reduce cabinet vibrations.
At higher volumes it rattled quite a bit, this problem was solved by putting felt in-between the back and the case
Step 12: The finished Radio
The case was made to get the most volume out of a tiny crappy speaker, with modern ones it has a deep rich tone.
With the mounting method of angling the speakers the way I did, it fills an entire house full of music.
It has an open back design that uses the walls to bounce the sound around as well.
Its great fun to put in a thumbdrive with 1940's radio broadcasts and replay to the Mercury Theater on the air!
Now dont go wild and convert any old radio some of them are very valuable, do your research and find out what its worth.
Some of the RCA ones are worth 1000's