Bose radios are known for their exceptional sound quality, but like any electronic device, they can malfunction. If your Bose radio isn’t working, don’t despair. This guide provides troubleshooting tips and a potential repair solution for a common issue in the 1996 Bose Wave Radio model.
A frequent cause of failure in the 1996 model is the Q1 transistor (2SC1394 or similar), a 1-watt NPN component. When Q1 shorts, it often damages two accompanying surface-mount resistors, part of a voltage splitter that generates 5V from the 10V regulator. Replacing these tiny resistors can be challenging. Therefore, a simpler, more cost-effective solution involves utilizing a used cell phone wall charger.
Using a Cell Phone Charger for Repair
Disassemble a used cell phone wall charger to access the internal circuit board. Cut the leads from the AC plug and the wires, leaving about 3-4 inches. This 5V output from the charger board will replace the faulty Q1 transistor and damaged resistors. Remove Q1, located near the bridge rectifier. Connect the positive (+5V) red wire from the cell phone charger board to the hole nearest the radio’s rear (toward the heat sink). Alternatively, connect it to pins 15/16 of IC601 or any point in the circuit with a 5V presence.
Insulate the wall wart board thoroughly using cardboard, paper, or Gorilla Tape to prevent shorts. If the charger board has an LED, leave it exposed to indicate operation. Position the board between the transformer and heat sink, securing it with hot glue if desired. Connect the 110V leads from the charger board to the AC pins where the transformer’s two-pin plug connects. Reassemble the radio carefully.
Alternative Repair with LM7805 Voltage Regulator
Another viable solution is replacing Q1 with an LM7805 positive voltage regulator. Connect the LM7805’s left pin to Q1’s center pin (collector), which carries 20V through a 50-ohm resistor. Connect the right pin to the pin facing the radio’s rear (5V output). Ground the center pin to a nearby ground point, such as a shield can or the grounded pin of the bridge rectifier (verify with an ohmmeter). Insulate the LM7805 to prevent short circuits. This method addresses a known weakness in the Bose Wave Radio’s design.
Accessing the Schematic
While Bose previously considered schematics confidential, they are now available online. You can find the service manual for the 1996 Bose Wave Radio, along with schematics for other Bose products, at websites like eserviceinfo.com. Refer to the schematic for detailed component locations and circuit diagrams.
Conclusion
A non-functioning Bose radio can be frustrating, but often the problem is solvable. By using a readily available cell phone charger or an LM7805 voltage regulator, you can potentially repair your 1996 Bose Wave Radio and enjoy its legendary sound once again. Remember to consult the schematic for precise guidance and always prioritize safety when working with electronics.
