Wednesday, December 02, 2015

JBL MA6004 Car amplifier troubleshooting and circuit diagram

Contents of this article

  • How to set the cross over
  • Troubleshooting the amplifier
  • Schematic diagram   

CAR AMPLIFIER 

JBL MA6004 

TROUBLESHOOTING AND CIRCUIT DIGRAM 

SETTING THE CROSSOVER
Determine your system plans and set the crossover mode switch accordingly. If your system design does not include a subwoofer with the MA6004, set the crossover mode to FLAT; if you are using speakers that are 5 inches in diameter or larger, skip to “Setting Input Sensitivity.” Initially set the crossover frequency control midway. While listening to music, adjust the crossover for the least perceived distortion from the speakers, allowing them to reproduce as much bass as possible.
For systems using a separate subwoofer, set the crossover mode to HP (high pass) for your full-range speakers. Adjust the crossover frequency to limit bass and provide increased system volume with less distortion.
For subwoofers, choose the highest frequency that removes vocal information from the sound of the subwoofer. If using the MA6004 or MA6002 to drive a subwoofer(s), set the crossover mode to LP (low pass).
SETTING INPUT SENSITIVITY
1. Initially turn the INPUT LEVEL control(s) to minimum (counter clockwise).
2. Reconnect the (–) negative lead to the boat’s battery. Apply power to the audio system and play a dynamic music track.
3. On the source unit, increase the volume control to 3/4 volume. Slowly increase the INPUT LEVEL control(s) toward “three o’clock” until you hear slight distortion in the music. Then reduce the INPUT LEVEL slightly until distortion is no longer heard.
NOTE: After the source unit is on, blue LEDs (on the top panel) will light, indicating the amplifier is on. If not, check the wiring, especially the remote connection from the source unit. Also refer to the “Troubleshooting” guide.
TROUBLESHOOTING
No audio (POWER LEDs are off)
No voltage at BATT+ or REM terminals, or bad or no ground connection
Check voltages at amplifier terminals with VOM
No audio (POWER LEDs are on)
Amplifier is overheated
Make sure amplifier cooling is not blocke at mounting location verify speaker-system impedance is within specified limits Voltage more than 16V or less than 8.5V on BATT+ connection
Check boat’s battery charging system
No audio (POWER LEDs flash)
Voltage less than 9V o BATT+ connection
DC voltage on amplifier output
Check boat’s charging system Amplifier may need service;
Distorted audio
Input sensitivity is not set properly, or amplifier or source unit is defective.
Check INPUT LEVEL setting; or check speaker wires for shorts or grounds
Distorted audio and POWER LEDs flash
Short circuit in speaker or wire
Remove speaker leads one at a time to locate shorted speaker or wire, then repair.
CIRCUIT DIAGRAM 
POWER SUPPLY 
POWER AMPLIFIER (ONLY ONE CHANNEL SHOWN )
PRE AMPLIFIER (ONLY ONE CHANNEL SHOWN )
CLICK ON THE IMAGES TO ZOOM IN