This project makes a Vintage MP3 Boombox with a few simple steps. By using an inexpensive Bluetooth MP3 player this old Candle Model JTR1296 Boombox can now be used to crank out some MP3 tunes direct from your smart phone. The boombox is a 12 volt DC player which can get power from D cell batteries, a 12 volt DC input jack or wall power (which is rectified using a transformer and bridge. Watch the video to see the interesting ground connection via a high value resistor to main power. Since the mains power input is non polarized this can be 110VAC. I have never seen this before. Was this common practice in this era?
A battery input jack was implemented so the system could run from a rechargable LiPoly battery. To prevent discharging below the safe range a cheap warning buzzer which is common on quad copters would be a good addition.
The MP3 player that was used normally operates from a 5 volt USB connection, the case was removed to allow direct soldering to the power connections. A simple LM7805 was used to convert the players 12 volt DC supply to the 5 volts that the bluetooth device needed. The stereo has a mic input which was an ideal connection to pump in the tunes. The result is a great looking boat anchor of a player that cranks out the tunes in style!
