Nexo NXAMP4X1 User manual

SERVICE MANUAL
PANEL LAYOUT .......................................................................................... 3
CIRCUIT BOARD LAYOUT ......................................................................... 4
SERVICE PRECAUTIONS ........................................................................... 5
OVERALL ASSEMBLY WIRING .................................................................. 7
DISASSEMBLY PROCEDURES ................................................................ 17
LSI PIN DESCRIPTION .............................................................................. 26
IC BLOCK DIAGRAM ................................................................................ 27
CIRCUIT BOARDS ..................................................................................... 33
TEST PROGRAM ....................................................................................... 52
INSPECTIONS ........................................................................................... 59
UPDATING THE FIRMWARE .................................................................... 64
PARTS LIST
IC & DIODE FIGURES
BLOCK DIAGRAM
CIRCUIT DIAGRAM
■CONTENTS
Copyright (c) NEXO S.A. All rights reserved. PDF ’ 08.01

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■WARNING
Components having special characteristics are marked and must be replaced with parts having specification equal to those originally
installed.
IMPORTANT NOTICE FORTHE UNITED KINGDOM
Connecting the Plug and Cord
WARNING: THIS APPARATUS MUST BE EARTHED
IMPORTANT. The wires in this mains lead are coloured in accordance with the following code:
GREEN-AND-YELLOW: EARTH
BLUE: NEUTRAL
BROWN: LIVE
As the colours of the wires in the mains lead of this apparatus may not correspond with the coloured markings identifying the terminals in your
plug, proceed as follows:
The wire which is coloured GREEN andYELLOW must be connected to the terminal in the plug which is marked by the letter E or by the safety
earth symbol or colored GREEN or colored GREEN andYELLOW.
The wire which is coloured BLUE must be connected to the terminal which is marked with the letter N or coloured BLACK.
The wire which is coloured BROWN must be connected to the terminal which is marked with the letter L or coloured RED.
WARNING: This product contains chemicals known to the State of California to cause cancer, or birth defects or other reproductive harm.
DO NOT PLACE SOLDER, ELECTRICAL/ELECTRONIC OR PLASTIC COMPONENTS INYOUR MOUTH FOR ANY REASON WHAT SO
EVER!
Avoid prolonged, unprotected contact between solder and your skin! When soldering, do not inhale solder fumes or expose eyes to solder/flux
vapor!
If you come in contact with solder or components located inside the enclosure of this product, wash your hands before handling food.

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• Rear Panel
■PANEL LAYOUT
1Power switch
2Amplifier indicators
3LCD display
4Encoder
5Navigation buttons (A & B)
6Volume indicators
1Mains connectors
2Balanced audio inputs with link
3Expansion slot
4Power outputs
• Front Panel
A0 216 7 53 48 9
6 5 73 24 1
7Mute buttons
8Select buttons
9Channel indicators
0Air intakes
AScrew holes for handles
5RS-232 Firmware update port
6GPIO port
7Rear end mounting holes

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■CIRCUIT BOARD LAYOUT
Rear Panel
INANL
PAANL
CONTROL
PAANL
PAANLPAANL
RS232-GPI
PSANL
OPT-AN
OPT-AN
PSANL
Front Panel
INANL
RS232-GPI
PN-AN
OUTANL
(PA unit)
(PA unit) (PA unit)
(PA unit)
OUTANL

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C323 C322
C317 C316
C324 C318
C325
C205
C344 C354
C345 C355
C357
C356
C348
C347
C319
C323 C322
REAR
FRONT
C317 C316
C324 C318
C325
C205
C201C201
R213R213
C344 C354
C345 C355
C357
C356
C348
C347
C319
D305
220 ohms/
10W
220 ohms/
10W 220 ohms/ 10W
220 ohms/
10W
220 ohms/10W220 ohms/10W
220 ohms/10W
220 ohms/10W220 ohms/10W
220 ohms/10W220 ohms/10W
220 ohms/10W
D306D306
1
3
4
2
CN316CN316
CN307 CN305CN307 CN305 CN308 CN309CN308
CN310CN310
CN309
6
7
5
■SERVICE PRECAUTIONS
Safety measures
• Some component parts on the PSANH circuit board main-
tain a high voltage even when the power is switched off.
For this reason to avoid an electrical shock, do not touch
the upper metallic part of the following capacitors until
the remaining voltage has discharged.
[Discharging Method]
Before starting the service work, connect discharging
resistors (220 ohms 10W) to the terminals indicated in
the figure below to discharge electricity. (7 points)
The required discharging time is about 10 seconds.Check
that the DC voltage between the terminals measures close
to 0 (zero) volts using a multi-meter to make sure that the
discharge is completed.
Note:
Do not touch the IC201 and its heat sink before discharg-
ing the C205.
PSANL circuit board
C316, C317, C322, C323
C318, C319, C324, C325
C344, C354
C345, C355
C347, C356
C348, C357
C205
1
2
3
4
5
6
7
D305: + pin <=> D305: - pin
D306: + pin <=> D306: - pin
CN305 <=> CN316
CN307 <=> CN316
CN308 <=> CN309
CN310 <=> CN309
R213: lead <=> C201
Capacitors Discharging point

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220 ohms/10W
C205
C205
C201
C201
7
PSANL circuit diagram
220 ohms/10W
220 ohms/10W
220 ohms/10W
C316
C316
D305
D305
C322
C354C344
C355C345
C356C347
C357C348
C354C344
C355C345
C356C347
C357C348
C317 C323
3
4
6
1
220 ohms/10W
C318
C319
C318
D306
D306
C324
C319 C325
2
C305
C307
C316
C305
C307
C316
220 ohms/10W
220 ohms/10W
220 ohms/10W
220 ohms/10W 5

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■OVERALL ASSEMBLYWIRING
This product has various cables (wires and connector assemblies) inside.To prevent touching component to the cables and/
or connection mistake, perform the cable connection and fixing cables according to the following instructions referring the
wiring diagram, P3 of the circuit diagram.
Notice: Since the following pictures are taken of the preproduction product, they may differ from the commodity products in
detail. However, the wiring and so on is not so differ between them. So, refer only to wiring and so on.
1. Wiring of the PN-AN circuit board
1) Process the flat cable (WK02100).(Fig. 1)
2) Connect the flat cable (WK02100) to the PN-AN circuit board. (Fig. 2)
3) Install the PN-AN circuit board to the front panel. (Fig. 3)
115 ±1 mm
25 ±1 mm
90˚ 90˚
115 ±1 mm
25 ±1 mm
90˚ 90˚
Fig. 1
Fig. 2 Fig. 3
2. Wiring of the power switch
1) Install the power switch to the front panel with its terminals set downward.(Fig. 4, 5)
Fig. 4 Fig. 5

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2) Confirm that the power switch is set to the off position as shown in the figure 6. (Fig. 6)
3) Twist the wires of the power switch assembly more than three times.
4) Connect the connector of the power switch assembly to the connector (CN103). (Fig. 7)
Fig. 6
Check
Check
Fig. 7
3. Wiring of the FAN
Connect the connector of the FAN to the each terminal. (Fig. 8)
Fig. 8
4. Attaching of the support cushion
Attach the support cushion (WN15950) at the specified
area on the pattern side of the CONTROL circuit board.
(Fig. 9)
Note: Be sure to remove the oil and the dust, etc.on the
attaching surface before attaching the support
cushion.
Fig. 9

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5. Wiring of the AC-INLET
a) Set a cord holder before installing the PSAN circuit board
on the enclosure. (Fig. 10) b) Set a ferrite-core at the specified area on the PSAN cir- cuit board, and fasten the ferrite-core with the cord holder.
(Fig. 11)
Fig. 10
c) Pass the live and neutral wires of the AC-INLET through the ferrite core’s hole twice and wind them to the ferrite core.
Screw an each screw terminal to the specified terminal. (Fig. 12, 13)
Fasten the GND wire with a cord holder. (U destination) (Fig. 12)
Screwing torque: GND LINE 1.8N •m / L, N LINE 0.78 •m
Fig. 11
d, e)Fix the wires to the terminal using the screws, and refer to the fig. 14 and fig.15 for the direction of each terminal.
Cord holder
Cord holder
Cord holder
Cord holder
Fig. 12 Fig. 13
Fig. 14 Fig. 15
(U.S.A. model) (Chinese model)

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6. Wiring of the PA-UNIT
Connect the wires to the connectors (CN401, CN403). (Fig. 16, 17)
Fig. 16 Fig. 17
NOTE: The followings are wires to be connected.
CN401:WK02080
CN403:WK90770
Install this PA-UNIT on the left side of enclo-
sure.
Hereafter, this unit is called PA-UNIT of CH1,
CH2.
NOTE: The followings are wires to be connected.
CN401:WK90790
CN403:WK17110
Install this PA-UNIT on the right side of enclo-
sure.
Hereafter, this unit is called PA-UNIT of CH3,
CH4.
Fig. 18
CH1
RED
CH3
YELLOW
CH2
BLUE CH4
GREEN
PSANHL
7. Wiring of the flat cable and fastening wires
Connect the following wires at first.
CN313:WK68760
CN201:WK68770
a) Install the RS232-GPI circuit board on the enclosure after connecting the wire (WM15830) to it.
b) Connect the wires (WK16830, WN52530) from each PA UNIT to the FASTON terminals of the OUTANL circuit board.
PA-UNIT (CH1, CH2) :WN52530 (ORANGE) –> CN805
WK16830 (YELLOW) –> CN806
PA-UNIT (CH3, CH4) :WN52530 (ORANGE) –> CN807
WK16830 (YELLOW) –> CN808
Then fold the wires (WK16830, WF44430) at the center of them, and fasten them with a cord holder. (Fig. 19)
c) Connect the wires (WK16820 x2) to the connectors (CN306, CN317) of the PSAN circuit board.
Connect the wire (WK14200) to the connector (CN202) of the PSAN circuit board.
Fasten these wires with a cord holder at the position as shown in the figure. (Fig. 19)
d) Connect the wire (WK14210) of PA-UNIT (CH3, CH4) to the connector (CN315).
Fasten the wire (WK14210) and the wires (WK16820 x2, WK14200) with a cord holder at the position where the wire (WK14210)
is vertically pulled from PA-UNIT. Before fastening, pull the wires (WK16820 x2, WK14200) toward the front panel side in
advance.
CN401
RED
CN403
BLUE CN401
YELLOW
CN403
GREEN
*The following figure describes a layout drawing of the PA-UNITs seen from the front panel. (Fig. 18)

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e) Connect the wire (WK14210) of PA-UNIT (CH1, CH2) to the connector (CN312).
Fasten the wire (WK14210) and the wire (WK02090) with a cord holder at the position where the wire (WK14210) is vertically
pulled from PA-UNIT. Before fastening, pull the wire (WK02090) toward the front panel side in advance.
f) Twist the wires (white, red and black) of PA-UNIT more than two times, and connect them to the FASTON terminals according
to the wire color displayed on the PSANL circuit board.
Then bend these wires, and fasten them with a cord holder. (Fig. 20)
Fig. 19
a)
a)
c)
b)
c)
b)
e) d)
b)
e)
f)
f)
f)
g)
h)
f)
d)
b)
Fig. 20

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g) Fasten these wires (WK17900, WK17910 and WK94710) with a cord holder to the hexagonal spacer. (Fig. 21)
h) Bend the wire (WK14200) and wire (WK16820) connected to the connector (CN317), and fasten the wires (WK14210,WK16820
x 2 and WK14200) with a cord holder. (Fig. 21)
Note: When connecting the connector assembly to the CONTROL circuit board, confirm that the connector housing pin
number of the connector assembly is the same as the connector pin number of the circuit board.
i) Fasten the wires (WK02080, WK90770) with a cord holder at the hole of the RS232-GPI circuit board. (Fig. 22)
j) Fasten the wires (WK02080, WK90770 and WK02070) with a cord holder at the hole of the enclosure.
Fasten the wires (WK90790, WK17110) with a cord holder at the hole of the enclosure. (Fig. 22)
k) Fasten the wires (WK90790, WK17110) with a cord holder at the hole of the OPT-AN circuit board.Then connect the flat cable
(WK02120). (Fig. 22)
l) Fasten the wires (WK02080, WK90770, WK90790, WK17110 and WK02070) with a cord holder at the position close to the
OPT-AN circuit board. (Fig. 22)
m) Bend the wire (WK02090), and fasten the wires (WK02090, WK68760 and WK68770) with a cord holder. (Fig. 22).
n) Bend the flat cable as shown in the figure. (Fig. 22)
Fig. 21
g)
h)
g)
h)

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Fig. 22
i) j)
*
1j)
*
2
j)
*
2
j)
*
1
m)
o)
n)
l) k) k)
k)
i) j)
*
1j)
*
2
j)
*
2
j)
*
1
m)
o)
n)
l) k) k)
k)
The hole of the enclosure
The hole of the enclosure

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Switch knob Switch knob
Switch knob Switch knob
9. Change of the destination
Set the knob position of the switch SW001 on the CONTROL circuit board as shown in the figure below. (Fig. 26, 27)
8. Color of the connectors connected to the connector CN012-CN015
Connect the connector assembly from the PA unit to the CONTROL circuit board as shown in the figure below. (Fig. 25)
Fig. 25
Fig. 26 Fig. 27
U destination CHN destination
o) Bend the flat cable to avoid touching the top cover. (Fig. 23, 24)
Fig. 23 Fig. 24
CN012
RED CN013 BLUE CN014 YELLOW CN015 GREEN

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10. Insulation distance between WK17110 and primary side capacitor
Perform wiring the connector assemblyWK17110 with care so that its uncovered portion with the SUMI tube does not touch
the capacitor C316 on primary side of the PSANL circuit board. (Fig.28, 29)
Fig. 28 Fig. 29
11. Insulation distance between WK14210 and primary side capacitor
Perform wiring the connector assemblyWK14210 with care so that its uncovered portion with the SUMI tube does not touch
the capacitors C317 and C319 on primary side of the PSANL circuit board. (Fig.30, 31)
Fig. 30
Fig. 31
C324 C318
C325 C319
C324 C318
C325 C319
C323 C322
C317 C316
C323 C322
C317 C316

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12. Prevention of touching WK02070 to connector terminal
Perform wiring the connector assemblyWK02070 with care so that its uncovered portion with the SUMI tube does not touch
the bare terminal of the connector CN203 of the RS232-GPI circuit board. (Fig. 32)
Fig. 32
13. Adhesive cloth tape
Cover the two screws near R587 and R588 in each PA unit (190 and 230) with adhesive cloth tape (185 and 225) as shown in
the figure below. (Fig. 33)
Fig. 33
IOAN circuit board
GPI circuit board
IOAN circuit board
GPI circuit board

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■DISASSEMBLY PROCEDURES
[650]: Bind Head Screw 4x8 MFZN2B3 (--)
(Fig. 1)
1. Top Cover (Time required: about 3 minutes)
1-1. Remove the thirteen (13) screws marked [650]. (Fig. 1)
1-2. The top cover can then be removed. (Fig. 1)
[650]
Top cover Top coverTop cover
[650]
[650] [650]

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[380]: Bind HeadTapping Screw-S 3x6 MFZN2W3 (--)
[400]: Bind HeadTapping Screw-S 3x6 MFZN2W3 (--)
[410]: Bind HeadTapping Screw-S 3x6 MFZN2B3 (--)
[430]: Bind HeadTapping Screw-S 3x6 MFZN2W3 (--)
(Fig. 2)
2. CONTROL Circuit Board, OPT angle and OPT-AN Circuit Board
(Time required: about 10 minutes)
2-1. Remove the top cover. (See procedure 1.)
2-2. Remove the four (4) screws marked [430]. (Fig.2)
2-3. Disconnect the connector assemblies from other units connected to the CONTROL circuit board. (Fig.2)
2-4. The CONTROL circuit board can then be removed. (Fig. 2)
2-5. Remove the three (3) screws marked [400] and the two (2) screws marked [410]. (Fig. 2)
2-6. Remove the OPT angle with the OPT-AN circuit board. (Fig. 2)
2-7. Remove the two (2) screws marked [380].(Fig. 2)
2-8. The OPT-AN circuit board can then be removed. (Fig. 2)
OPT angle
OPT angle
[430][400] [400]
[410]
[400]
[380]
[430]
CONTROL
OPT-AN
OPT-AN

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[277]: Plastic Rivet NRP-345 (--)
[280]: Flat HeadTapping Screw-B 3x8 MFZN2B3 (--)
[285]: Bind HeadTapping Screw-S 3x6 MFZN2W3 (--)
[290]: Bind HeadTapping Screw-B 3x8 MFZN2B3 (--)
(Fig. 3)
3. OUTANL Circuit Board (Time required: about 15 minutes)
3-1. Remove the top cover. (See procedure 1.)
3-2. Remove the CONTROL circuit board and the OPT angle. (See procedure 2.)
3-3. Remove the eight (8) screws marked [280], the one (1) screw marked [290] and the one (1) screw marked [285].(Fig. 3)
3-4. Disconnect the connector assemblies from other units connected to the OUTANL circuit board. (Fig. 3)
3-5. The OUTANL circuit board with the two (2) insulation sheets and the two (2) shields can then be removed. (Fig. 3)
3-6. Remove the three (3) plastic rivets marked [277].(Fig. 3)
3-7. Remove the insulation sheet 1, the shield 1, the shield 2 and the insulation sheet 2 from the OUTANL circuit board. (Fig. 3)
[280]
[290]
[285]
[277]
OUTANL
OUTANL
Insulation sheet 1
Insulation
sheet 2
Shield 1
Shield 2

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4. PSANL Circuit Board (Time required: about 20 minutes)
4-1. Remove the top cover. (See procedure 1.)
4-2. Remove the CONTROL circuit Board and the OPT angle. (See procedure 2.)
4-3. Remove the OUTANL Circuit Board. (See procedure 3.)
4-5. Remove the two (2) screws marked [150], and remove the ACPS connector assembly. (Fig. 4)
4-6. Remove the nine (9) screws marked [100], the one (1) hexagonal spacers marked [90] and the one (1) hexagonal spacer
marked [95]. (Fig. 4)
4-7. Disconnect the connector assemblies from other units connected to the PSANL circuit board. (Fig. 4)
4-8. The PSANL circuit board can then be removed.(Fig. 4)
[90]: Hexagonal Spacer H=89 B=5.5 (--)
[95]: Hexagonal Spacer H=41 B=5.5 (--)
[100]: Bind HeadTapping Screw-S 3x6 MFZN2W3 (--)
[150]: Flat HeadTapping Screw-B 3x8 MFZN2B3 (--) (U destination)
[150]: Bind HeadTapping Screw-B 3x8 MFZN2B3 (--) (O destination)
(Fig. 4)
ACPS connector assembly
[100]
[150]
[90]
[100]
[95]
[100]
PSANL
[100]