P 7520 (serv.man3) - JBL Car Audio User Guide / Operation Manual. Page 7

7

No audio

Low/No Remote On Voltage

Check connections; Test turn-on voltage

Speakers are not connected 

Check wiring; use VOM/DVM to

or are blown

measure speaker coil resistance

Distorted audio

Input sensitivity is not set properly

See Setting Input Sensitivity on previous page

Audio lacks “punch”

Speakers are wired with wrong polarity

Check polarity of connections; 
refer to Applications

Audio cycles off and on;

A protection circuit is turning the 

Verify the following: electrical system is

Amber protection LED 

amplifier off and on

between 5 ~ 18 V dc; temperature is not 

(JBL badge on top panel)

over 194°F (90°C); no short circuits; speaker 

is flashing

loads are not less than 2 ohm (4 ohms in 
mono)

Audio cycles off and on; Amber 

GAIN is set too high

Set Input Sensitivity correctly

protection LED (on top panel) 

(see previous page)

is flashing

Fuse blows

Incorrect wiring or short circuit 

Check connections; refer to Applications 

Many different system configurations are
possible using the crossovers and pre-
amp outputs featured in Power Series
amplifiers. If you are considering
expanding you system beyond what is
shown here, please consult your local JBL
installation specialist who is experienced
in designing complex mobile audio
systems. 

Use the following guide to identify
symptoms and solve problems. Make
sure the vehicle’s electrical system is
working properly and power is reaching
the amplifier.