JBL Professional MPC-XU owner manual II. Installation, Tools needed

II. Installation

CAUTION: The MPC-XU contains active components which can be damaged by electro- static discharge (ESD). Be sure to practice standard ESD precautions, and always ground yourself and your workstation before handling exposed circuit cards.

Installing the MPC-XU requires PC board soldering skills. Only qualified service technicians should attempt it. Any authorized JBL service center can perform the installation.

The MPC-XU installs on the amplifier input board of any JBL MPA or MPC amplifier.

Tools needed:

Soldering iron

¼-inch (6.3 mm) nutdriver Phillips screwdriver Wire cutters Rosin-core solder

Desoldering iron or other suitable desoldering equipment (Do not use desoldering braid; it can damage the solder pads on the input board and might not remove solder adequately.)

CAUTION: Preparing the input board for installation of the MPC-XU involves removing solder from feed-through holes on a 2-sided circuit board. Excessive heat can damage the solder pads you will be working on. Proper equipment and experience with desoldering delicate PC board circuitry is essential to successfully perform the procedure. Damage caused by improper installation is not covered under warranty.

1	Turn off the amplifier and disconnect the AC power cord from the AC source. Disconnect
	all cables from the amplifier’s input panel.
2	Position the amplifier so the rear of the chassis is facing you. The input panel is located on
Input panel	the left side of the rear panel. See Figure 2a.

CH2 12 10	8
14	6
18	4
24	2
- d B	0

LEVEL

CH2	INPUT	CH1		12	10	8	CH1
	G R O U N D	ST E R E O		14			6
				18			4
				24		0	2
					- d B
	INPUT	PARALLEL	BRIDGE		LEVEL

1 LOW IMPEDANCE	AUDIO TRANSFORMER		CH1
CDIRH. OUTPUT	0	7 0 100 ISOL .OUTPUT

BR I D G E	70V	25V
	10 0 V
MO N O

2 LOW IMPEDANCE	AUDIO TRANSFORMER		CH2
CDIRH. OUTPUT	0	7 0 100 ISOL .OUTPUT

BR I D G E	70V	25V
	10 0 V
MO N O

Wire jumpers: W303/304 and W403/404 (MPC); or W305/ 306 and W405/W406 (MPA)

Solder holes for MPC-XU

Figure 2a. The input panel’s location on the rear panel of the amp

Figure 2b. The input panel (MPC) Figure 2c. The input panel (MPA)

3Locate and remove the screws securing both the upper blank and the lower input panels to the rear side of the chassis (2 screws on each mini panel). The upper blank panel will simply drop off when its screws are removed.

4Gently pull the lower input panel out from the amplifier. Once it is removed, you will notice a ribbon cable connecting the input PC board to the amplifier. Disengage the locking wing clamps on the ribbon header and carefully remove the ribbon head from the socket on the board. Now the input panel assembly is completely free from the amplifier.

5 Desolder and remove the wire jumper pairs indicated in Figure 2b or 2c.

6Under where the jumpers were located, you’ll find two rows of solder pad holes—one with 10 holes and another with 12 holes. Remove the solder from all 22 holes.

7With the input panel facing you and the component side of the MPC-XU board facing away from you, carefully insert the header pins of the MPC-XU fully into the socket holes. Turn the assembly over and solder the MPC-XU in place. Make sure all the header pins are well soldered. Visually inspect for cold solder joints and verify that you have sufficient clearance to re-install the ribbon connector on the top side of the assembly. Finish by trimming the MPC-XU header pins as required.

2