JBL E150 Service Manual

							
E150P               
 
TEST SET-UP AND PROCEDURE 
 
 
General Function 
UUT = Unit Under Test 
 
1)  Connect one line level input cable (RCA) from signal generator to either Right or Left Lev el input on UUT. LEVEL 
control should be full counterclockwise (MIN).  Make sure the LFE/Normal switch is in the NORMAL position. 
2)  Turn on generator, adjust to  100mV, 50Hz. 
3)  Plug in UUT; Turn Main Power switch ON. LED’s on the  top panel may be either Red or Green. Turn LEVEL control 
full clockwise (MAX). Low Pass control should be set fully clockwise (150Hz). 
4)  LED should turn Green; immediately bass response should be heard and felt from port tube opening. 
5)  Turn off generator, turn LEVEL control full y counterclockwise (MIN), disconnect RCA cables. 
6)  Connect one pair of speaker cables to either high level input terminal on UUT. Cables should be connected to an  integrated amplifier fed by the signal generator. 
7)  Turn on generator and adjust so that speaker level output is  1.0V, 50Hz. Turn LEVEL control full clockwise (MAX). 
8)  Green LED should light, immediate bass response should be heard and felt from the port tube opening. 
 
Sweep Function 
 
1)  Follow steps 1-4 abov e, using a sweep generator as a signal source. 
2)  Sweep generator from 20Hz to 300Hz. Listen to the cabinet and drivers for any rattles, clicks, buzzes or any other  noises. If any unusual noises are heard, remove driver and test. 
 
Driver Function 
 
1)  Remove driver from cabinet; detach + and - wire clips. 
2)  Check DC resistance of driver; it should be  5.8 ohms. 
3)  Connect a pair of speaker cables to driver terminals. Cables should be connected to an integrated amplifier fed by a  signal generator and adjust so that speaker level output is  5.0V. 
4) Sweep generator from 20Hz to 1kHz. Listen to driver for any rubbing, buzzing, or other unusual noises.  
						

							
E150P              
 
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         TECH TIPS 
 
Troubleshooting tips and solutions to common service problems 
 
For models: E150P,E250P and PB10,PB12 (Revision 2) *    TIP# JBLTT2003-04 Rev1 
  
Subject:  Replacing MOSFETS Q18, Q22  
In the event you need to replace MOSFET transistors Q18 or Q22 as part of a repair, it is important to use 
ONLY the JBL part# FE106401110  or only the brands: International Rectifier, or Fairchild.  
Replace both Q18 and Q22 MOSFET’s in the circuit, even if only one seems to be damaged.  
Do NOT mix & match these components from different manufacturers, or batches.  They should be 
identical.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 * Late version PB10 or PB12 subwoofers (Revision 2 in the service manual) can be identified by: 
•  Amplifier serial number starts with “HA” 
•  Output transistors in the open, on a large black heatsink 
•  Large plastic cup enclosing the rear of the amp assembly 
•  Main PCB, bottom, solder-side contains all SMD dev ices 
 
E150P              
 
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A.  Power Amp Section
Resistance
Check
Resistance from S+ (SPK O/P) to GND should be >1M Ω (NO LOAD)
Resistance from V+ (C6 P+) to V- (C8 P-) gradually Fully CHARGED sho\
uld read >10k  Ω
Resistance from V+ (C6 P+) to S+ (SPK O/P) should read >1MΩ
Resistance from V- (C8 P-) to S+ (SPK O/P) should read >1M Ω
2. Power Up LED RED
      With a 5mV signal to Low level input, LED should change to GREEN
     -Voltage measurements (DVM)
OP AMP
LEDP-U4(1) P-U4(7)
RED 0Vrms 8VDC
GREEN 6.3Vrms -10.7VDC
3. D.C. Operation
     -Voltage measurements (DVM) on CLASS D POWER AMP
Between V+ Q4(E) Q1(C)Q10(C)U7(1) U7(2) U7(4) U7(6) U7(7) U7(8)
And This
PointGND V- GND GND GND GND GND GND GND GND
Get this
Reading45.9V 0V -45.9V 0V -45.9V -45.7V -45.5V 0V 0V 4.7V
4. Check Switching Frequency
•
  Oscilloscope -  USE THE PROBE TIP TO U6(7) TO GND
•   Reading 100kHz +/-10%,22Vp-p
B. Pre Amp Section Line Level Input Sensitivity
     -Set up Turn level, X’OVER FREQ POT Fully CW and LFE switch off Generator Set at 100mV@50Hz
Signal to Line level input
E150P              
 
DETAILED TROUBLESHOOTING
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 - Voltage measurementsOP AMP
U2(1) U2(14) U2(8) U3(7) U3(1) U3(14) U3(8) U5(7) U5(1) SPEAKER
O/P
133.6mV 200.2mV 245.9mV 314.8mV 314.9mV 350mV 1.67V 1.452V 2.098V 15.3V
2. High Level Input Sensitivity
     -Set up Turn level, X’OVER FREQ POT Fully CW and LFE switch off
                              Set Generator at 1.15V@50Hz Signal to High level input
     -Voltage measurements 15.3V at speaker output
3. Low-Pass
    -Set up Set Generator at 100 mV@100Hz Signal to 
Line level input
Measure voltage at S+ speaker output
     -Voltage measurement
X’OVER FREQ. Setting Output
CW 10.72V
CCW 2.165V
4. LFE 
     -Set up Set Generator at 100mV@200Hz Signal to 
Line level input
Measure voltage at S+ speaker output
LFE  switch  Setting Output
Normal 2.9V
LFE 7.62V
See flow chart next page for diagnostics.
E150P              
 
DETAILED TROUBLESHOOTING (CONT'D)
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CAUTION : SPEAKER OUTPUT IS FLOATING AND IS  NOT  PROTECTED AGAINST A SHORT
                           TO  GROUND.  ALL TEST INSTRUMENTS CONNECTED T\
O THE OUTPUT  MUST
                           BE  FLOATING.  ATTACH  THE  SCOPE  PROBE TIP \
TO S - and  REFERENCE
                           LEAD TO S+.
                                                   (A 10mV signal may n\
eed from the input to trigger the  Switch turn on)
                                                                        \
                                                          no
                     no
                                                                        \
                                                   yes
              yes
                                                                        \
                                                          no
                     no
                                                                        \
                                                   yes
              yes
                                                                        \
                                                          no
                     no
                                                                        \
                                                   yes
              yes
                                                                        \
                                                          no
                     no
                                                                        \
                                                  yes
               yesSTART
Check +/-15V-MOD +/-15V voltage  at U 6(8),U6(4)
Discharge C37,Check fuse
transformer, L4,
rectifier, C6 and C8
Use scope to check switching
frequency U6(7) 100KHz
 +/-10% , ~22Vp-p
Check Q4(E) TO V-
 = 0V D.C.
Power up with no signal inputLED RED
OK
OK
OK
OK
OK
OK
OK
OK
Check
MUTE(+8V) and
Q24,Q25,Q26
Use scope to
check O/P U7(6) and GND
90Vp-p square wave shown
Check
L2,L3,C71,C72, C73
,C74
I/P:10mv/50HZ
Check +15V/SW Q4(E) TO V-
15V
Replace
Q18,Q22
CLASS  D AMP OK
END
Check
U7,Q16,Q17,
Q20,Q21,R87,
D26,D35,C64
Check
FB1,FB2,C45,
C50,C60,C63,
R81,R82
Check
U7(1) = -33V
Check
MUTE(-10.7V),
And
Q24,Q25,Q26
Resistance check
(no load)
between V+ V-,
V+ O/P,V- O/P
and O/P to GND
is > 10K
E150P              
 
DETAILED TROUBLESHOOTING (CONT'D)
FLOW CHART
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