Say what you will, but there's never been a better time to enjoy music than now. We can stream or download high quality tracks of nearly every song ever made to our pockets wirelessly, effortlessly, and for nearly free. While listening to your favorite songs on your newest iGalaxyJam device by Dre can be fun, you've got a love for vintage electronics and that old-school-cool, the new devices just can't match up. You've got a killer sound blaster of a boombox tucked away in a corner and want to bring it back to life. AM and FM are alright, but what if you want to hear the latest and greatest hits, sans commercials and crappy DJs, and hear it all... from space?! Enter: the Satellite Radio Boombox. In this Instructable, I'll show you an easy, non-destructive way to modify a classic cassette-playing boombox to mount and power a satellite radio receiver.
Step 1: Gather Parts and Materials
Step 2: Remove the Tape Cover
Although it would be possible to mount the XM radio outside of the case and use a cassette-to-line-in audio adapter, I wanted to make a more compact solution that didn't require modifying the case permanently. Since there are countless models of boomboxes, this will be a general guide on what to look for when modifying your own.
Let's start breaking things down! I recommend getting a couple small Tupperware containers to sort out any small screws as they are removed.
I knew I wanted to safely remove the tape cover and keep it in the event I wanted to return the boombox to it's original condition, so I needed to be mindful about the actions I took so that I could retrace my steps to repairing the box. I began by carefully examining the outside of the case, looking for visible seams and screws that would allow me to remove the front face. I started the deconstruction by removing every visible piece that seemed to come off easily. Thankfully the knobs and switch covers easily popped off with a nice tug. I also unscrewed the antenna and set it aside. The Sanyo designers kindly included little arrows around the back of the case to indicate the screws I needed to remove (if only modern electronics were so friendly!). Once I removed the four screws from the back case, I was able to turn the boombox on its back and slide the face off. Once I had the face free, I could access the tape door. Once I removed the button assembly at the bottom, the tape door popped out easily and I re-installed the buttons.
Step 3: Modify the Power Supply
The included power adapter for the XM radio is intended to plug directly into a cigarette lighter socket, but we'll need to power it directly from the boombox's power supply, so we'll have to modify it. We'll be stuffing the power supply into some empty space inside the case, so we'll need to remove the molded shell.
First, pop out the spring contacts so you can reach inside the case with a flat head screwdriver.
Next, pry apart the case. You can use a vise to gently squish the case to break along it's seam, but take care not to crush the circuit inside.
Clip away the spring contacts and one of the wires that connects to the board.
Cut and strip two wires about a foot long each.
Solder your power wires to the board; red on the tip and black on the spring contact wire.
Put heat-shrink around the new wire connections.
Wrap the circuit in electrical tape.
Use large diameter heat shrink to cover the end of the tape and wires.
Examining the circuit that connects to the battery contacts, determine which pads connect to power and ground.
Solder the appropriate wires to the circuit board.
Step 4: Add a Line Input
The sound from the XM radio is line-level from an audio jack on the side of dock. Going with the theme of compactness, we'll solder wire directly to the solder pads on the main circuit. We'll need to do a bit more dis-assembly to get to the pad. Make sure your stereo has a line-level input, as this would damage the phono amplifier. My boombox has a switch between phono and line-level input but only has phono (RCA) connectors available.
Remove the tape deck mechanism (mine came out with only few screws).
Remove the radio circuit and mechanism.
Unscrew the main circuit board and locate the solder pads for the audio connection.
Cut off and strip one end of the included stereo 3.5mm cable.
Test which wires connect to the audio signals (in my case the yellow wire was ground).
Solder the audio wires to the signal pads on the circuit board.
Solder the ground wire to one of the ground connections on the circuit board.
Tie the wire to an available cable to relieve stress on the soldered connections.
Step 5: Make the Adapter Plate
I designed stacking plates out of wood to act as a dummy cassette adapter. I used a laser cutter, but the holes can be easily cut out with a drill press too. I also designed an etched face plate to cover the hole into the case.
If you have access to a laser cutter, cut out the plates from 3mm ply and 3mm black acrylic (or any color really).
If you are using solid wood, counter bore the four large outer holes for the wide black screws that came with the dock. You can still use the .pdf as a template for drilling.
Screw in the adapter to the dock.
Step 6: Final Assembly
Place the power supply in an available space.
Replace the tape mechanism.
Slide the coiled wire into the available space.
Fish the audio, power, and antenna through the available holes.
Mount the XM radio assembly.
Plug in the power, antenna, and audio connections.
Remove the sticky-back for the antenna wire holder.
Grab your ghetto-blaster and go!