9
The UF-2 contains active components which can be damaged by electrostatic discharge (ESD). Be sure
to practice standard ESD precautions and always ground yourself and your workstation before handling
exposed circuit cards.
CAUTION: Preparing the input board for installation of the UF-2 involves removing
solder from feed-through holes on a two-sided circuit card. Excessive heat can easily
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
following procedure. Please contact the QSC Customer Service Department if you
feel you might not be qualified to perform the installation yourself. One last warning:
damage caused by an improper installation will void the warranty.
Before you start any work, turn off the amplifier power switch and disconnect the AC power cord from the
AC source. Disconnect all cables from the amplifier’s input panel.
Position the amplifier so the rear of the chassis is facing you. The input panel is located on the left side of
the rear panel. See Figure 10.
Begin the installation by locating and removing the screws securing both the upper blank and lower input
panels to the rear side of the chassis (two screws on each mini panel). See Figure 10. The upper blank panel
will simply drop off when its screws are removed.
Gently 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. See Figure 11.
Next, desolder and remove the wire jumper pairs W305/W306 and W405/W406 (W303/W304 and W403/
W404 on MXa Series amplifiers). Under where the jumpers were are two rows of solder pad holes, one with
10 holes and another with 12. These are the Mini-Slot “sockets.” See Figure 11.
Figure 10
Figure 11
CH1
CH2
CH1
CH2
BRIDGE
MONO
BRIDGE
MONO
LOW IMPEDANCE
LOW IMPEDANCE
DIR. OUTPUT
DIR. OUTPUT
ISOL.OUTPUT
ISOL.OUTPUT
AUDIO TRANSFORMER
AUDIO TRANSFORMER
70V
70V
25V
25V
100V
100V
0 70 100
0 70 100
0
0
-dB
-dB
10
10
8
8
6
6
4
4
2
2
24
24
18
18
14
14
STEREO
12
12
CH2 INPUT CH1
CH2 CH1
PARALLEL BRIDGE
LEVEL
LEVEL
GROUND
INPUT
Input card
