background image

 

TROUBLESHOOTING

SYMPTOM

LIKELY CAUSE

SOLUTION

No audio 

No voltage at BATT+ 

Check voltages at

(POWER LED

or REM terminals, 

amplifier terminals

is off)

or bad or no ground 

with VOM

connection

No audio

DC voltage on 

Amplifier may need

(PROTECT LED 

amplifier output 

service; see enclosed

flashes every 

warranty card for

4 sec.) 

service information 

No audio 

Amplifier is

Make sure amplifier

(PROTECT

overheated

cooling is not blocked

LED is on)

at mounting location;
verify speaker-system
impedance is within 
specified limits (see 
“Specifications” on the 
next page)

No audio

Voltage less than 9V on 

Check vehicle

(PROTECT 

BATT+ connection

charging system for

and POWER

defective voltage 

LEDs flash)

regulator

I-E/OPT LED

Amplifier is being 

Check INPUT

is on all times 

overdriven

LEVEL setting; 

(not flashing)

see previous page 

No audio

Voltage more than 16V

Check vehicle

(PROTECT 

or less than 8.5V on

charging system for

LED is on)

BATT+ connection

defective voltage 

regulator

Distorted audio

Input sensitivity is 

Check INPUT 

not set properly, or

LEVEL setting; or

amplifier or source 

check speaker wires

unit is defective

for shorts or grounds

Distorted audio

Short circuit in 

Remove speaker leads

and PROTECT 

speaker or wire

one at a time to locate

LED flashes 

shorted speaker or 
wire, then repair 

Music lacks 

Speakers are not 

Check speaker

“punch”

connected properly

connections for
proper polarity

Power 

Amplifier 

    

 

PX300.4

 

Summary of Contents for PX300.4

Page 1: ...PX300 4 4 CHANNEL POWER AMPLIFIER SERVICE MANUAL JBL Consumer Products 250 Crossways Park Dr Woodbury New York 11797 Rev1 2 2004 ...

Page 2: ...put Sensitivity RCA type 250mV 6V THD Noise 4 Ohms 0 04 Signal to Noise 95 dB Maximum Current Draw 78A Fuse Replacement 30Ax2 External Dimensions Length 12 312mm Width 17 432mm Depth 2 9 16 66mm JBL continually strives to improve its products New materials production methods and design refinements are introduced into existing models without notice as a routine expression of our design philosophy F...

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Page 5: ...et REAR and FRONT X OVER MODE to FLAT on input panel FLAT HP LP MODE ST INPUT MODE MO Figure 6 The JBL Px300 4 amplifier is set to stereo mode to drive front and rear pairs of full range speakers NOTE To limit bass sent to full range speakers set X OVER MODE to HP See page 6 to set FREQ and SLOPE Figure 7 The JBL Px300 4 amplifier is set to drive a stereo component system and a subwoofer with a no...

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Page 7: ...OTECT BATT connection charging system for and POWER defective voltage LEDs flash regulator I E OPT LED Amplifier is being Check INPUT is on all times overdriven LEVEL setting not flashing see previous page No audio Voltage more than 16V Check vehicle PROTECT or less than 8 5V on charging system for LED is on BATT connection defective voltage regulator Distorted audio Input sensitivity is Check INP...

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Page 10: ...0756 RESISTOR CARBON FILM 1 5WJ 820 OHM 4 R110 210 310 410 RES 00 00633 RESISTOR CARBON FILM 1 5WJ 1K OHM 20 R7 20 21 34 35 42 109 134 144 209 R234 244 309 334 344 409 434 444 809 812 RES 00 00595 RESISTOR CARBON FILM 1 5WJ 1 2K OHM 6 R28 43 172 272 372 472 RES 00 00598 RESISTOR CARBON FILM 1 5WJ 1 5K OHM 4 R154 254 354 454 RES 00 00602 RESISTOR CARBON FILM 1 5WJ 1 8K OHM 2 R383 483 RES 00 00644 R...

Page 11: ... CAPACITOR MYLAR 63V TL 473J 4 C135 235 335 435 MYC 00 00157 CAPACITOR MYLAR 63V TL 823J 16 C110 111 113 114 210 211 213 214 310 311 C313 314 410 411 413 414 MYC 00 00083 CAPACITOR MYLAR 63V TL 104J 1 C26 MYC 00 00156 CAPACITOR MYLAR 63V TL 184J 2 C316 416 MYC 00 00066 CAPACITOR MYLAR 63V TL 474J 2 C315 415 MYC 00 00085 CAPACITOR MYLAR 63V TL 105J 2 C13 29 MAIN PCB ICO 00 00022 I C PWM IC DIP 14 T...

Page 12: ... 2 SUB 28 573A0 CUSHION BKT TR A FIBER 87 0x15 0x0 5t 2 SUB 28 574A0 CUSHION BKT TR B FIBER 99 0x15 0x0 5t 2 SUB 33 513A0 CUSHION RUBBER A RUBBER 5 0x7 0x1 6t TR 4 THERMISTOR 1 5 SUB 33 006A0 CUSHION RUBBER B RUBBER 012 0x05 0x2 0t ACCESSORY 4 4 SIL 34 001A0 SILICON PAD SP1000 22 0x0 3t 780mm SUP 29 502A0 SUPPORTPCB NYLON L 4 5mm 7 SUB 27 524A0 SWITCH DECAL FELT 12 0x7 0x0 3t 6 SUB 28 519A0 PAPER ...

Page 13: ...Power Amplifier PX300 4 ...

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Page 17: ...X 15 X 1 5T NI P BKT 05 521A0 2 10 BRACKET TR B CR 103 X 15 X 1 5T NI P BKT 05 521A0 2 11 CUSHION BKT TR A FIBER 87 X 15 X 0 5T SUB 28 573A0 2 12 CUSHION BKT TR B FIBER 99 X 15 X 0 5T SUB 28 574A0 2 13 CUSHION RUBBER A 12 X 7 X 1 6T SUB 33 513A0 5 14 SILICON PAD SP1000 22 X 0 3T SIL 34 001A0 15 SUPPORT PCB NYLON L 4 5mm SUP 29 502A0 6 16 SWITCH DECAL FELT 12 X 7 X 0 3T SUB 27 524A0 6 17 TUBE 5 X 4...

Page 18: ...7 1 2 3 4 5 6 8 A B C D E ...

Page 19: ...A B C D E PX300 4 ...

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Page 21: ...7 1 2 3 4 5 6 8 A B C D E ...

Page 22: ...A B C D E PX300 4 ...

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Page 24: ...7 1 2 3 4 5 6 8 A B C D E ...

Page 25: ...A B C D E PX300 4 ...

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