MS 8 - JBL Car Audio Service Manual (repair manual). Page 18

Read JBL MS 8 Service Manual online

TrOUBLeshOOTiNG
If your MS-8 doesn’t seem to be working the way it should, read this section to 
see if the problem and possible solution are listed here. If, after you try all of the 
solutions listed here, the problem persists, contact JBL Customer Service at 
516.255.4JBL (4525).
POWer
sOUNd
The power LED does not 
illuminate.
Symptom
Symptom
Possible Cause
Possible Cause
Solution
Solution
The power LED illuminates, 
but the display does not 
illuminate.
There is no sound in all 
channels.
Improper input connections.
Calibration/setup procedure 
has not been performed.
Incorrect input is selected
on the MS-8
The MS-8’s System Volume 
is turned all the way down.
Set the MS-8 System 
Volume at –20dB. See 
Acoustic Calibration, on 
page 32, and Volume Up 
and Volume Down Buttons
on page 35.
Select the correct input 
using the MS-8’s Input 
Selection menu. See Input 
Selection Menu, on page 35.
Perform the calibration/
setup procedure. (The 
procedure must be 
performed before the MS-8 
will pass an audio signal 
through to its outputs.) See 
Calibration/Setup, on page 
24.
Confirm that all the required 
channels of the source unit 
are properly connected. See 
Audio Inputs, on page 7.
The +12V, Gnd or Rem In 
terminals are not properly 
connected.
The fuse is blown.
The display is not properly 
connected.
The MS-8’s microprocessor 
needs to be reset.
Replace the fuse with an 
identical 25A fuse.
Check the connections at 
display and at main unit. 
See Connections: Display
on page 14.
Press Reset button with a 
pen or similar object. See 
Resetting the 
Microprocessor, on page 41.
Confirm that all power 
connections are correctly 
made according to this 
manual. See Connections: 
Power, on page 5.
The head-unit or source-unit 
volume control is turned all the 
way down.
Turn the head-unit or 
source unit volume up to a 
normal level. 
42
TROUBLESHOOTING
 
 MS-8   
 
 
 
 
 
 
 
 
 
 
 
   
      
 
 
 
NOTE PAGE NUMBER REFERENCES IN THIS SECTION REFER TO THE OWNER'S MANUAL
17
Page of 110
Display

Click on the first or last page to see other MS 8 service manuals if exist.