JBL S4HC Synthesis Four
JBL Loudspeaker Troubleshooting/Repair Tips
Most customers prefer to do simple loudspeaker repairs themselves. By following the steps below, a majority of loudspeakers can be returned to their original factory performance with minimum effort. Choose the example that best describes the problem you are experiencing.
Problem 1: No sound or distorted sound from one loudspeaker in a pair (or set)
Connect the dead/distorting loudspeaker to a different amplifier channel (one that had a functioning loudspeaker connected to it). If it functions normally, the problem is not
Refer to the wiring diagram and exploded view below. The network is a small circuit board found on the inside of the terminal cup, or mounted to an inside wall of the enclosure. It sends
or abnormal. If everything looks normal, connect the network to the drivers from another matching loudspeaker. MAKE SURE you attach the correct wires to each driver – mid- and
Problem 2: No sound or distorted sound from one or more (but not all) drivers in an enclosure
Remove the problem driver(s) from the enclosure and make sure all wires are secure and connected. If they are, proceed with the following test: Woofer or midrange driver – Connect the driver’s + and – input terminals directly to the loudspeaker wires from your receiver/amplifier and play some music at a reasonable volume. If the driver now sounds normal (produces a clean, undistorted sound), the network is most likely defective. Tweeter – Replace the tweeter with a functioning tweeter from another loudspeaker. If the tweeter now functions normally (produces clean, undistorted sound), the original tweeter is defective. If the replacement tweeter also sounds distorted or produces no sound, the network is most likely defective.
Problem 3: Loudspeakers distort, rattle or pop at higher volumes
This is usually NOT a loudspeaker problem. Common causes are too much power (playing the loudspeakers too loud and causing them to distort), an amplifier with not enough power (the amplifier can’t produce the required volume without distorting), excessive equalization (turning the tone controls too far clockwise, and/or engaging the loudness/bass boost button on your receiver) or some combination of the above. If only one loudspeaker is exhibiting the problem, and you’re confident that it’s not caused by too little power/too much power/excessive equalization, see solutions for Problems 1 and 2.
WIRING DIAGRAM |
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NETWORK | ||
TRANSDUCER | ||
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TRANSDUCER | ||
TRANSDUCER | ||
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EXPLODED VIEW
23 (8) | 8 (2) |
| S4HC Cabinet – Not for Sale |
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14 | 24 | (4) |
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21 | 7 |
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(4) | 12 |
| 25 | (6) |
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| S4HC |
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10 18 (6)
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ITEM |
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NO. | DESCRIPTION | QTY. | PART NO. | NO. | DESCRIPTION | QTY. | PART NO. |
1. | Survey Card | 1 | 19. | Flower Pot | 1 | ||
2. | Owner’s Manual | 1 | 20. | Crossover Network | 1 | ||
3. | Warranty Card | 1 | 21. | Screw (midrange) PB, HXS, | 4 | ||
4. | Mounting Bracket | 4 |
| #6 x .75," ZNC |
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5. | Top & Bottom Pads | 2 | 22. | Screw (network) PB, PPH, | 4 | ||
6. | Outer Carton | 1 |
| #6 x 5/8," BLK |
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7. | Tweeter | 1 | 23. | Screw (woofer) PB, HXS, | 8 | ||
8. | Woofer | 2 |
| #6 x 1," ZNC |
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9. | Midrange | 1 | 24. | Screw (tweeter) PB, HXS, | 4 | ||
10. | Woofer Gasket | 2 |
| #6 x .75," ZNC |
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11. | Midrange Gasket | 1 | 25. | Screw (input cup) PB, HXS, | 6 | ||
12. | Tweeter Faceplate | 1 |
| #6 x .75," BLK |
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13. | Tweeter Bezel Gasket | 1 | 26. | T Nut 1/4 x 20 | 8 | ||
14. | JBL Logo | 1 | 27. | Screw (bracket mounting) MS, | 8 | ||
15. | Terminal Cup Ass’y | 1 |
| PPH, 1/4 x 20 x .75" BLK |
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16. | Cup Ass’y Gasket | 1 | 28. | Screw (S4HC installation) MS, | 8 | ||
17. | Grille | 1 |
| PPH, |
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18. | Grille Retainer | 6 |
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