Tim's Electronic Projects: Restoring a 1947 RCA 8-x-541 AM tube radio and adding bluetooth

Steps I took on repairing and updating a 1947 RCA 8-x-541 AM tube radio to include Bluetooth.

First I bought an old (non working) set off of eBay.Look around for a bargain. There are quite a few out there at low prices if you have the time to tinker. If not buy a working model and add a BT module to it.

First step was to remove all of the electronics and bezels.

Next I had to verify that this was Bakelite. The easiest and best way is to run the "plastic" under really hot water. If it smells like formaldehyde, then its Bakelite.

Next I took the case and dials to the tub (literally). Use a mild detergent (dawn) on Bakelite and most likely it will really clean up. (Who knows how many layers of pledge / old English / cigarette smoke have built up over the years).

If its still dull take Brasso to it. You just need a mild polishing paste to really make the Bakelite shine.

Next I did something that I did not find anywhere online to restore Bakelite but it really brought out the shine. I used a car wax on the unit. Buff it out and it looks amazing.

Electronics

I pulled the radio unit out and observed that the am antenna was completely gone.

Also the wires that should have led to the light bulb were completely gone. The power cord was gone too.

So first I put on a new power cord and removed an am antenna out of on old (modern) radio and soldiered it in. I tried plugging it in but no go. So I put 2 flash light bulbs in series to get the right voltage for the odd 1947 bulb and it fired right up.

The 2 bulbs would not light up though no matter what I tried. I finally just replaced it with a resistor.The tubes are run in series and would not heat up unless you added that.

I then realized the crazy thing was finally working. I tuned into an am station and all work perfect. I still wanted the radio dial lit up though so I added an old cell phone charger and spliced in the end off of an old extension cord.

Plugged in the cell charger soldiered on a resistor put an led where the old bulb was suppose to be with a generous amount of hot glue. Now the unit stays lit whenever the unit has power but not turned on. Tubes eat up a TON of power. This makes it more of a decorative piece.

Lastly I added an aux line in on the old radio. Looking at the potentiometer I found where the input from the am antenna runs to the amp. I did this through trial and error. If you try this yourself try to use an audio source that you do not care about. I used a 1990 Sony Walkman.

Once you found the spot splice in an audio cable and you now have an old radio that you can hook almost anything to. (If you find that the volume knob does not change the volume level of your input keep trying a different input.)

I then plugged in a BT adapter and I was streaming 1940's jazz through my new awesome radio.

On a side note. This radio is old. Nothing is insulated. The entire unit has 110 running through it. I had to go by trial and error to find the right port to splice into. So beware and attempt this at your own risk. Also I plugged a $8 BT adapter into the plug. I would never risk an iPhone or something that expensive to this until I do a little more testing of voltages.