NAD M-3 Service manual
SERVICE MANUAL
SERVICE MANUAL
M3 C/
AH
MODEL : M3SERVICE MANUAL
©
NAD
2005
NAD
ELECTRONICS
INTERNA
TIONAL
T
ORONT
O
M3 C/AH
INTEGRATE AMPLIFLER
M3 C/AH
INTEGRATE AMPLIFIER
INTEGRATE AMPLIFIER
CONTENTS
SECTION 1 . . . .SUMMARY
SECTION 2 . . . .CABINET & MAIN CHASSIS
SECTION 3 . . . .ELECTRICAL
SECTION 4 . . . .REPLACEMENT PARTS LIST
SECTION 1
SUMMARY
CONTENTS
PRODUCT SAFETY SERVICING GUIDELINES FOR AUDIO PRODUCTS
............. 1-2
SERVICING PRECAUTIONS ........................................................................... 1-3
• General Servicing Precautions
• Insulation Checking Prodedure
• Electrostatically Sensitive Devices
SPECIFICATIONS ........................................................................................... 1-6,7
1-1
ALIGNMENT PROCEDURE ............................................................................. 1-4,5
• POWER DRIVEN VOLTAGE
• IDLING CURRENT
• BALANCE INPUTS CMRR
1-2
SUBJECT: GRAPHIC SYMBOLS
PRODUCT SAFETY SERVICING GUIDELINES FOR AUDIO PRODUCTS
A.C. VOLTMETER
GOOD EARTH GROUND
SUCH AS THE WATER
PIPE. CONDUIT. ETC
PLACE THIS PROBE
ON EACH EXPOSED
METAL PART
CAUTION : DO NOT ATTEMPT TO MODIFY THIS
PRODUCT IN ANY WAY, NEVER PERFORM CUSTOMIZED INSTALLATIONS WITHOUT MANUFACTURER’S
APPROVAL. UNAUTHORIZED MODIFICATIONS WILL
NOT ONLY VOID THE WARRANTY, BUT MAY LEAD TO
YOUR BEING LIABLE FOR ANY RESULTING PROPERTY DAMAGE OR USER INJURY.
SERVICE WORK SHOULD BE PERFORMED ONLY
AFTER YOU ARE THOROUGHLY FAMILIAR WITH ALL
OF THE FOLLOWING SAFETY CHECKS AND SERVICING GUIDELINES. TO DO OTHERWISE,INCREASES
THE RISK OF POTENTIAL HAZARDS AND INJURY TO
THE USER.
WHILE SERVICING, USE AN ISOLATION TRANSFORMER FOR PROTECTION FROM A.C. LINESHOCK.
SAFETY CHECKS
AFTER THE ORIGINAL SERVICE PROBLEM HAS
BEEN CORRCTED. A CHECK SHOULD BE MADE OF
THE FOLLOWING.
SUBJECT : FIRE & SHOCK HAZARD
1.BE SURE THAT ALL COMPONENTS ARE POSI-
TIONED IN SUCH A WAY AS TO AVOID POSSIBILITY
OF ADJACENT COMPONENT SHORTS.THIS IS ESPECIALLY IMPORTANT ON THOSE MODULES WHICH
ARE TRANSPORTED TO AND FROM THE REPAIR
SHOP.
2. NEVER RELEASE A REPAIR UNLESS ALL PROTECTIVE DEVICES SUCH AS INSULATORS, BARRIERS,
COVERS, SHIELDS, STRAIN RELIEFS, POWER
SUPPLY CORDS, AND OTHER HARDWARE HAVEBEEN REINSTALLED PER ORIGINAL DESIGN. BE
SURE THAT THE SAFETY PURPOSE OF THE POLARIZED LINE PLUG HAS NOT BEEN DEFEATED.
3. SOLDERING MUST BE INSPECTED TO DISCOVER
POSSIBLE COLD SOLDER JOINTS, SOLDER
SPLASHES OR SHARP SOLDER POINTS. BE CERTAIN TO REMOVE ALL LOOSE FOREIGN PARTICLES.
4. CHECK FOR PHYSICAL EVIDENCE OF DAMAGE
OR DETERIORATION TO PARTS AND COMPONENTS.
FOR FRAYED LEADS, DAMAGED INSULATION
(INCLUDING A.C. CORD). AND REPLACE IF NECES-
5. NO LEAD OR COMPONENT SHOULD TOUCH A
RECIVING TUBE OR A RESISTOR RATED AT 1 WATT
OR MORE. LEAD TENSION AROUND PROTRUNING
METAL SURFACES MUST BE AVOIDED.
6. ALL CRITICAL COMPONENTS SUCH AS FUSES,
FLAMEPROOF RESISTORS, CAPACITORS, ETC.
MUST BE REPLACED WITH EXACT FACTORY TYPES,
DO NOT USE REPLACEMENT COMPONENTS OTHER
THAN THOSE SPECIFIED OR MAKE UNRECOMMENDED CIRCUIT MODIFICATIONS.
7. AFTER RE-ASSEMBLY OF THE SET ALWAYS PERFORM AN A.C. LEAKAGE TEST ON ALL EXPOSED
METALLIC PARTS OF THE CABINET, (THE CHANNEL
SELECTOR KNOB, ANTENNA TERMINALS. HANDLE
AND SCREWS) TO BE SURE THE SET IS SAFE TO
OPERATE WITHOUT DANGER OF ELECTRICAL
SHOCK. DO NOT USE A LINE ISOLATION TRANSFORMER DURING THIS TEST USE AN A.C. VOLTMETER, HAVING 5000 OHMS PER VOLT OR MORE SENSITIVITY, IN THE FOLLOWING MANNER; CONNECT A
1500 OHM 10 WATT RESISTOR, PARALLELED BY A
.15 MFD. 150.V A.C TYPE CAPACITOR BETWEEN A
KNOWN GOOD EARTH GROUND (WATER PIPE,
CONDUIT,ETC.) AND THE EXPOSED METALLIC
PARTS, ONE AT A TIME. MEASURE THE A.C. VOLTAGE ACROSS THE COMBINATION OF 1500OHM
RESISTOR AND .15 MFD CAPACITOR. REVERSE THE
A.C. PLUG AND REPEAT A.C. VOLTAGE MEASUREMENTS FOR EACH EXPOSED METALLIC PART. VOLTAGE MEASURED MUST NOT EXCEED 75 VOLTS
R.M.S. THIS CORRESPONDS TO 0.5 MILLIAMP A.C
ANY VALUE EXCEEDING THIS LIMIT CONSTITUTES A
POTENTIAL SHOCK HAZARD AND MUST BE CORRECTED IMMEDIATELY.
THE LIGHTNING FLASH WITH APROWHEAD SYMBOL. WITHIN AN EQUILATERAL TRIANGLE, IS INTENDED
TO ALERT THE SERVICE PERSONNEL TO THE PRESENCE OF UNINSULATED “DANGEROUS VOLTAGE”
THAT MAY BE OF SUFFICIENT MAGNITUDE TO CONSTITUTE A RISK OF ELECTRIC SHOCK.
THE EXCLAMATION POINT WITHIN AN EQUILATERAL TRIANGLE IS INTENDED TO ALERT THE SERVICE
PERSONNEL TO THE PRESENCE OF IMPORTANT SAFETY INFORMATION IN SERVICE LITERATURE.
SERVICING PRECAUTIONS
1-3
CAUTION
this service data and its supplements and addends, read and
follow the SAFETY PRECAUTIONS. NOTE: if unforeseen
circumstances create conflict between the following servicing
precautions and any of the safety precautions in this publication,
always follow the safety precautions.
Remember Safety First:
General Servicing Precautions
1. Always unplug the Stereo amplifier AC power cord from the
AC power source before:
(1) Removing or reinstalling any component, circuit board,
(2) Disconnecting or reconnecting any internal electrical
(3) Connecting a test substitute in parallel with an electrolytic
Caution: A wrong part substitute or incorrect polarity
2. Do not spray chemicals on or near this Stereo amplifier or
any of its assemblies.
3. Unless specified otherwise in this service data, clean
electrical contacts by applying an appropriate contact
cleaning solution to the contacts with a pipe cleaner,
cot tont ipp e d swa b, or com par able s oft a ppl i cat or.
Unless specified otherwise in this service data, lubrication
of contacts is not required.
4. Do not defeat any plug/socket B+ voltage interlocks with
which instruments covered by this service manual might be
equipped.
5. Do not apply AC power to this Stereo amplifier and/or any
of its electrical assemblies unless all solid-state device heat
sinks are correctly installed.
6. Always connect test instrument ground lead to the
appropriate ground before connecting the test instrument
positive lead. Always remove the test instrument ground lead
last.
Insulation Checking Procedure
Disconnect the attachment plug from the AC outlet and turn the
power on. Connect an insulation resistance meter (500V) to the
blades of the attachment plug. The insulation resistance
between each blade of the attachment plug and accessible
conductive parts (Note 1) should be more than 1 M-ohm.
Note 1: Accessible Conductive Parts including Metal panels,
Input terminals, Earphone jacks, etc.
: Before servicing the Stereo amplifier covered by
module, or any other assembly.
plug or other electrical connection.
capacitor.
installation of electrolytic capacitors may result in an
explosion hazard.
Electrostatically Sensitive (ES) Devices
Some semiconductor (solid state) devices can be damaged
easily by static electricity. Such components commonly are
called Electrostatically Sensitive (ES) Devices. Examples of
typical Es devices are integrated circuits and some field effect
transistors and semiconductor chip components.
The following techniques should be used to help reduce the
incidence of component damage caused by static electricity.
1. Immediately before handing any semiconductor component
or semiconductor-equipped assembly, drain off any
electrostatic charge on your body by touching a known earth
ground. Alternatively, obtain and wear a commercially
available discharging wrist strap device, which should be
removed for potential shock reason prior to applying power to
the unit under test.
2. After removing an electrical assembly equipped with ES
devices, place the assembly on a conductive surface such as
aluminum foil, to prevent electrostatic charge buildup or
exposure of the assembly.
3. Use only a grounded-tip soldering iron to solder or unsolder
ES devices.
4. Use only an antistatic solder removal device. Some solder
removal devices not classified a “anti-static” can generate
electrical charges sufficient to damage ES devices.
5. Do not use freonpropelled chemicals. These can generate
electrical charge sufficient to damage ES devices.
6. Do not remove a replacement ES device from its protective
package until immediately before you are ready to install it.
(Most replacement ES devices are packaged with leads
electrically shorted together by conductive foam, aluminum
foil, or comparable conductive material).
7. Immediately before removing the protective material from the
leads of a replacement ES device, touch the protective
material to the chassis or circuit assembly into which the
device will be installed.
Caution: Be sure no power is applied to the chassis or circuit,
and observe all other safety precautions.
8.Minimize bodily motions when handing unpackaged
replacement ES devices. (Normally harmless motion such as
the brushing together of your clothes fabric or the lifting of
your foot from a carpeted floor can generate static electricity
sufficient to damage an ES device.)
ALIGNMENT PROCEDURE
A. POWER DRIVEN VOLTAGE(PSU BOARD)
Connect a DC Millivoltmeter to TP601/TP701 1 and 2 pin, then adjust VR601/VR701(6.8kohms)
for 0V±0.1V.
B. IDLING CURRENT(AMP BOARD)
1.Connect a DC Millivoltmeter betweenTP301 2 pins, then adjust VR301 (200ohms) for 7-8mV
reading on meter.
2.Connect a DC Millivoltmeter between TP401 2 pins, then adjust VR401 (200ohms) for 7-8mV
reading on meter.
3. Watch for 10minutes, to make sure it is arround 7mV
PSU BOARD
AMP BOARD(L/R)
321
123
1-4
C. BALANCE INPUTS CMRR
1.Volum set 0dB, Input 2V/10KHZ common mode sinwave signal at L channel Balance input,Connect a AC
Millivoltmeter to preout1L then adjust R565 for lowest output level.
2. Volum set 0dB,Input 2V/10KHZ common mode sinwave signal at R channel Balance input,Connect a AC
Millivoltmeter to preout1R then adjust R564 for lowest output level.
1-5
SPECIFICATIONS
1-6
NAD M3 INTEGRATE AMPLIFIER
Note: Specifications are measured in accordance with EIA
Standard RS-490 (IHF A-202) for amplifiers
Power Amplifier Section
Continuous output power into 4/8 ohms
(Minimum RMS power per channel, both channels
driven, With no more than the rated distortion)
Rated distortion (THD)(20Hz –20kHz) ≤0.004%
Channel Separation ≥100dB
(MAIN IN, 60W Out at 8Ω,1kΩ shorted, 1kHz)
Clipping power, 1kHz 220W
(Maximum continuous power per channel)
Dynamic Headroom at 8 ohms 4.2dB
Dynamic power
(Maximum short-term power per channel )
Damping factor ≥150
8ohms
4ohms
2ohms
180W (17dBw)
≥280W
≥480W
≥785W
Signal to noise ratio(refer 1W A-weighted) ≥≥100dB
Slew rate ≥≥20V/μsec
T.H.D and SMPTE I.M. ≤0.01%
(Distortion from 250mW to rated output)
IHF I.M. (CCIF IM) and T.I.M distortion ≤0.005%
(From 250mW to rated output))
Input impedance 20kΩ//680pF
Input sensitivity rate power into 8ohms) roF ( 1.38V
Power amp gain 29dB
Preamplifier Section
Input Impedance single-ended input 150k Ω //500pF
balanced input
120kΩ //100pF
Signal-to-Noise ratio 110dB ref 500mV
1-7
(A-weighted, line In, Pre-Out)
Rated distortion (THD)(20Hz –21kHz) ≤0.005%
Channel Separation
(1kHz 2V Line/balanced IN, 2V Pre-Out)
Input Sensitivity 320mV for 2V out
Input Overload Line input
Balanced input
Frequency response(5Hz-70KHz)
THD (SUB OUT) ≤0.01%
(2V CD in, 2V SUB out; 50Hz, 80kHz LPF)
THD (ZONE 2 OUT)
(2V CD IN, 1kHz, 80kHz LPF) ≤0.01%
≥110dB
≥10V
≥9 V
< +/-0.3dB
Outputs
Preamp output impedance 100 Ω
Zone2 output impedance 600 Ω
Controls
Treble ±5dB at 10kHz
Bass ±5dB at 100Hz
Pre-in ,Power AMP out,input 2V
Signal-to-Noise ratio, A-weighted 107dB ref 1 W out
(500mV CD in, SPK out, 8Ω, A weighted)
Rated distortion (THD)(20Hz –20kHz) ≤0.008%
Input sensitivity 450mV
(CD in, SPK out, at rated power, volume max.)
Channel Separation ≥100dB
(CD in, 20W out at 8Ω, 1kΩ shorted, 1kHz)
Frequency response Bd3.0-/+
PHYSICAL SPECIFICATIONS
Dimensions(W x H x D)
Net 17.2x5.3x15.2”(435x135x386mm)
Gross 17.2x5.8x17.2”(435x147x435mm)
Net Weight 51.8lbs(23.5kg)
Shipping Weight 68.3lbs(31.0kg)
2-1
SECTION 2
CABINET & MAIN CHASSIS
CONTENTS
EXPLODED VIEWS. ... . .. . . .. . . .. . ... . .. . . .. . . .. . ... . .. . . .. . . .. . ... . .. . . .. . . .. . ... . .. . . .. . . .. . ... . .. 2 -2
1. Cabinet and main frame section .. . . .. . . .. . ... . .. . . .. . . .. . ... . .. . . .. . . .. . ... . .. . . .. . . .. . ... . .. . . .. . 2 -2
2. Packing accessory section . .. ........... . . . . . . . .. ........... . . . . . . . ........... . . . . . . . ........... . . . . . . . 2-3
3. Exploded view parts list... . . . . . . . .. ........... . . . . . . . .. ........... . . . . . . . ........... . . . . . . . ........... . . 2- 4 , 5
EXPLODED VIEWS
1. Cabinet and main frame section
S010
S009
S008
C015
C016
C015
C017
S007
S006
S004
C013
C014
A005
S002
A004
C018
A003
S014
A006
A002
S011
C020
C019
C004
C022
S001
S018
T001
S013
A001
S017
C026
C024
S016
C023
C007
C025
C008
PR03
PR02
S016
PR01
C029
C028
C012
C009
C011
C027
PR06
R003
S013
S026
R006
PR04
R009
C010
S025
R007
PR05
R008
R010
R001
R002
R011
S001
R005
S015
R004
S023
PR10
PR12
S024
PR11
PR09
S005
S001
F006
F004
F013
F005
F007
F001
S001
F002
S002
F003
F008
S001
S021
S025
F009
C006
F011
F010
S020
S002
S003
S003
F012
S019
S004
C021
S019
S012
C001
S004
S004
C005
C002
S022
C003
PR08
PR07
S002
2-2
2. Packing accessory section
P006
P005
P003
P004
P016
P015
P014
P013
P012
P011
P010
P009
P008
P007
P002
P001
2-3
3. Exploded view parts list
REF.NO PART NO. DESCRIPTION Qty. REF.NO PART NO. DESCRIPTION Qty.
C001
C002
C003
C004
C005
C006
C007
C008
C009
C010
C011 01-50312-00
C012 01-50311-00
C013 94-048001-2
C014
C015
C016
C017
C018
C019
C020
C021
C022
C023
C024
C025
C026
C027
C028
C029
01-50306-02 RAMP Board Assy 1 67-048024-0 Rear Panel（CCC） 1
01-50306-01 LAMP Board Assy 1
01-50305-00 Power Board Assy 1
01-50307-02 StandbyBoard(Buttom) Assy 1
01-50307-21 StandbyBoard(Top) Assy 1
01-50303-00 Connect Board Assy 1
01-50301-00 Balance Board Assy 1 77-048010-0
01-50309-00 PREM Board Assy 1 77-048011-0
Tone Board Assy 1
L Input Board Assy 1
Transformer label 2
68-048002-0 Shielding Box 2
Transformer rubber pad 4
Transformer 2
F001
F002
F003
F004
F005
F006
F007
F008
F009
F010
F011
F012
F013
18-53231-01
68-048001-1 HS Fixl Bar 4
75-048022-0 Bus Bar Washer 4
85-008001-1 Spacer Support 1
69-048013-0 Copper Spacer 2
69-048031-0 Copper Spacer-Screw 4
66-011011-0 Connectible Bracket 2
66-048004-0 Blance pcb Shielding 1
71-048010-0 Vol. Knob Assy 1
70-048011-0 M3 Fascia 2 1
01-50302-00 Encoder Board Assy 1
76-048010-0 Window lens 1
70-048013-0 Power Button 1
92-048001-0 Spring for Button 8
87-048002-0 Input Button Pad 7
70-048012-1 Input Button 7
01-50304-00 FPP Board Assy 1
70-048010-1 M3 Fascia 1 1
87-048003-0 Power Button Pad 1
R001
R002
R003
R004
R005
R006
R007
R008
R009
R010
R011
A01
2csiD lateM0-800100-66
4A raB suB1-010840-96
4B raB suB1-110840-96
4yssA tooF0-010840-38
1revoC CP0-210840-67
1telnI CA00-20170-71
1sneL DEL1-100800-67
1aicsafbuS1-300840-76
1revoC poT0-100840-76100T
A02
A03
A04
A05
A06
PR01
PR02
PR03
PR04
PR05
PR06
PR07
PR08
PR09
PR10
PR11
PR12
S001
S002
S003
S004
S005
S006
S007
S008
S009
S010
01-50308-02 SPK Board（R） 1
01-50308-01 SPK Board （L） 1
77-048001-0 Bindingpost Plug Red(C) 4
17-03001-03 HS Bindingpost Red Assy 4
17-03001-04 HS Bindingpost white Assy 4
Double step washer Red 10
Double step washer White 10
69-048016-0 Counternut 20
77-048002-0 Bindingpost Plug White(C) 4
11-01101-03 Power Switch 1
30-60480-00 RCA Shorting Plug 2
70-048005-0 Small Heatsink B 2
70-048004-0 Small Heatsink 2
66-005009-0 Tr. Clamping
78-005005-0 Insulated Cashion
69-048024-0 Copper Spacer-Screw 16
66-018005-0 Tem. SW. Clamper 2
69-048032-0 Copper Spacer 2
85-048001-0 Pcb Spacer 2
69-048027-0 PRE-BUSBAR L 1
69-048028-0 PRE-BUSBAR R 1
17-01001-16
17-01001-15
16-53013-00
70-048002-0 Module Base 2
70-048003-0 Module Cover 2
66-048001-0 Tr. Bracket 4
78-048004-0 Insulated Cashion 8
61-023208-0 Screws, BTB3×8 35
61-224512-1 Hex Screws 4×12 51
61-224508-1 Hex Screws 4×8 10
61-023206-0 Screws, BTB3×6 40
62-010802-0 Nut M8 2
63-020820-1
63-010816-0 Washers φ8 2
63-020616-0
61-226510-0 Hex Screws 6×10 8
64-208070-0 Bolts M8×70 2
HS RCA Red Assy 10
HS RCA White Assy 10
Pre. Module pcb Down 2
Pre. Module pcb Up 2
Spring Washers φ8
Spring Washers φ6
lenaP raeR1-400840-761sissahC2-200840-76 （C） 1
lenaP raeR2-410840-764knistaeH0-100840-07 （AH） 1
16
16
2
8
2-4
REF.NO PART NO. DESCRIPTION Qty. REF.NO PART NO. DESCRIPTION Qty.
S011
S012 62-050302-0 PEM NUT-PCB M3×0.5
S013
S014
S015
S016
S017
S018
S019
S020
S021
S022
S023
S024
S025
S026
P001
P002
P003
P004
P005
P006
P007
P008
P009
P010
P011
P012
P013
P014
P015
P016
61-023212-0 Screws, BTB3×12 2
16
61-223506-1 Hex Screws w/Tooth washer 24
61-223514-0 Hex Screws 3×14 16
61-023106-0 Screws, STB3×6 4
61-373506-0 Machine Screws M3×6 14
63-010408-0 Spring Washers φ4 2
62-010402-0 Nut M4 2
61-024108-0 Screws, STB4×8 4
63-020411-0 Washers φ4 2
62-010302-1 Nut M3 6
61-023506-1 Screws, MB3×6 16
61-062206-1 Screws, BTF2×6 8
61-062108-1 Screws, STF2×8 4
61-023508-0 Screws, MB3×8 10
61-022206-0 Screws, BTB2×6 8
Packing List
88-048001-0 Shipping Box 1
1xoB tfiG0-200840-88
89-048001-0 Polyfoam-Bottom 1
89-048002-0 Polyfoam-Cap 1
87-048004-0 Non-woven-cloth Bag 1
1gabyloP0-100500-09
88-043003-0 Accessories Box 1
30-45030-11 Instruction Nanual 1
30-45030-02 Instruction Nanual 1
30-45030-03 Instruction Nanual CCC 1
89-048003-0 Little Polyfoam A 1
30-28601-00 Batteries CR2025 1
30-10300-00 Remote Control 1
1teehS xoB0-400340-88
1C droC CA00-05201-51
15-10125-00 AC Cord AH
15-10250-03 AC Cord CCC 1
30-17200-01 Remote Control ZR3 1
89-048004-0 Little Polyfoam B 1
30-22100-00 Batteries AA 2
2-5
SECTION 3
ELECTRICAL CONTENTS
ELECTRICALTROUBLESHOOTING GUIDE
1. Power check flow
2. Preamp operation flow
DETAILS AND WAVEFORMS ON SYSTEM TEST AND DEBUGGING
1. SYSTEM 11MHz CLOCK
2. AT89C51 reset signal
3. Volume control DATA and CLOCK
4. REC(ZONE) select DATA and CLOCK
5. Input select DATA and CLOCK
BLOCK DIAGRAMS
1. POWER DISTRIBUTE DIAGRAM
2. PREAMP SIGNAL PATH
3. SYSTEM CONTROL PATH
CIRCUIT DIAGRAMS
1. POWER AMPLIFIER BOARD Circuit DIAGRAM
2. PREAMP BOARD Circuit DIAGRAM
3. STANDBY AND SPEAKER BOARD Circuit DIAGRAM
4. ENCODER AND CONNECT BOARD Circuit DIAGRAM
5. FRONT PANEL BOARD Circuit DIAGRAM
6. BALANCE INPUT BOARD Circuit DIAGRAM
7. POWER BOARD Circuit DIAGRAM
PRINTED CIRCUIT DIAGRAMS
1. Preamp Main board(PREM)
2. Preamp LCH input board(PREL)
3. Preamp tone control board(PRET)
4. Power supply board(PSU)
5. Balance amplifier board(BAL)
6. Connect board(CON)
7. Encoder board(ENC)
8. Speaker board(SPK)
9. Front pannel board(FPP)
10. Standby board Bottom(STBB)
11. Standby board top(STBT)
3-2
3-2,3
3-4,5
3-6
3-6
3-6
3-7
3-7
3-8
3-9
3-9
3-10
3-11
3-12
3-12
3-13
3-14
3-15
3-16
3-17
3-18
3-19
3-19
3-20
3-20
3-21
3-22
3-23
3-23
3-23
3-24
3-25
3-26
3-1
ELECTRICAL TROUBLESHOOTING GUIDE
1.Power Check Flow
Power switch on
Amber LED ON?
NO
5V is Right ?
NO
Check S1 and its cable
Check F901
Check the standby Transformer
Check IC1 on the standby board
YES
Press the standby button
Hear the relay’s click?
YES
NO
YES
Check the MCU on the keyboard
Check U84 and Q82
Check the D81
Check the MCU on the keyboard
Check Q91 Q92 and OP91
Check if the main transformers
has been plugged in
+/-70V
un-regulated power supply
is correct?
YES
+/-20V
power supply is correct?
YES
+/-18V
power supply is correct?
NO
NO
NO
Check F902 and F903
Check the main transformer
Check B603 B604 B703 B704
Check D602 D603 D702 D703
Check PSU PCB
Check R648 R649 R748 R749
Check B605 B705
Check IC603 IC604 IC703 IC704
Check the PCB track
Check the sockets and plugs
Check 1Q21 1Q22 2Q21 2Q22
A
YES
3-2
A
+72V
power supply is correct?
YES
-72V
power supply is correct?
YES
12V on the
preamp relayis correct?
NO
NO
NO
Check R646 R647 R746 R747 R622
Check B606 B706
Check Q609 Q610 Q611
Check the PCB track
Check R623
Check Q612 Q613
Check Q990 Q991
Check D990 D991
YES
THE END
3-3
2.Preamp operation flow
Power on
Amber LED change to
blue?
YES
Wate for 10 second
Hear the relay’s click?
NO
NO
Check FPP board
Check 24V relay suply
Check U113,U108,U213,U208
Check HCLK,HDATA,FUNC signal
YES
Press listen,mode,biamp key
to change input and out put
mode
Relay respond properly?
YES
NO
Input 2V RMS 1K sinewave,turn
volume to 0dB,measure
preoutput level and THD
Level=2V±0.1V ?
YES
B
NO
THD>0.01%?
YES
Check U101,U201,U106,U206
NO
Check U105,U205,U104,U107,U204,U207
Check VOL_ CLK,STB,DATA(L/R) signal
Check VOLA signal and 1Q28
Check Q103,Q203,Q101,Q102,Q201,Q202
3-4
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