JBL owner manual JBL S4HC Synthesis Four, Exploded View, Wiring Diagram

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 loudspeaker-related. If the loudspeaker still makes no sound or sounds distorted, a wire may have become loose or disconnected, the network (also known as a crossover) may be defective, the drivers (woofer, tweeter, etc.) may be defective or, in very rare cases, all may be defective.

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 low-frequency sounds to the woofer, high-frequency sounds to the tweeter and, if applicable, mid-frequency sounds to the midrange driver. Make sure all wires are secure and connected. Look for components on the network that look burnt, “bulged,”

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 low-frequency sounds can damage the tweeter! If there is still no sound or distorted sound, the network is defective. If there is clean undistorted sound, the drivers are defective.

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
NETWORK	HIGH-FREQUENCY
	TRANSDUCER
338527-001
	335663-001
	MID-FREQUENCY
	TRANSDUCER
	336327-001
LOW-FREQUENCY
TRANSDUCER	LOW-FREQUENCY
335899-001	TRANSDUCER
	335899-001

EXPLODED VIEW

23 (8)	8 (2)		S4HC Cabinet – Not for Sale
	26
14	24	(4)
21	7
(4)	12		25	(6)
			S4HC
		11	15
9		19
	20		16
	22	(4)

10 18 (6)

17

ITEM				ITEM
NO.	DESCRIPTION	QTY.	PART NO.	NO.	DESCRIPTION	QTY.	PART NO.
1.	Survey Card	1	331384-001	19.	Flower Pot	1	334072-001
2.	Owner’s Manual	1	338636-001	20.	Crossover Network	1	338527-001
3.	Warranty Card	1	338322-001	21.	Screw (midrange) PB, HXS,	4	908302-012
4.	Mounting Bracket	4	337722-001		#6 x .75," ZNC
5.	Top & Bottom Pads	2	337826-001	22.	Screw (network) PB, PPH,	4	903401-010
6.	Outer Carton	1	338635-001		#6 x 5/8," BLK
7.	Tweeter	1	335663-001	23.	Screw (woofer) PB, HXS,	8	903802-016
8.	Woofer	2	335899-001		#6 x 1," ZNC
9.	Midrange	1	336327-001	24.	Screw (tweeter) PB, HXS,	4	908302-012
10.	Woofer Gasket	2	335657-001		#6 x .75," ZNC
11.	Midrange Gasket	1	335656-001	25.	Screw (input cup) PB, HXS,	6	908301-012
12.	Tweeter Faceplate	1	335695-001		#6 x .75," BLK
13.	Tweeter Bezel Gasket	1	336613-001	26.	T Nut 1/4 x 20	8	339051-001
14.	JBL Logo	1	48003-01	27.	Screw (bracket mounting) MS,	8	900501-012
15.	Terminal Cup Ass’y	1	336616-002		PPH, 1/4 x 20 x .75" BLK
16.	Cup Ass’y Gasket	1	336773-001	28.	Screw (S4HC installation) MS,	8	900201-006
17.	Grille	1	337598-001		PPH, 8-32 x .375" BLK
18.	Grille Retainer	6	333249-001