PIONEER DJ DJM-750MK2 User manual

ORDER NO.
Pioneer DJ Corporation 6F, Yokohama i-Mark Place, 4-4-5 Minatomirai, Nishi-ku, Yokohama, Kanagawa 220-0012 Japan
2017 Pioneer DJ Corporation
DJM-750MK2
QRT1011
DJ MIXER
DJM-750MK2
THIS MANUAL IS APPLICABLE TO THE FOLLOWING MODEL(S) AND TYPE(S).
THIS SERVICE MANUAL SHOULD BE USED TOGETHER WITH THE FOLLOWING MANUAL(S).
Model Type Power Requirement Remarks
DJM-750MK2 LSYXJ AC 110 V to 240 V
DJM-750MK2 UXJCB AC 110 V to 240 V
DJM-750MK2 XJCN AC 220 V
Model Order No. Remarks
DJM-750MK2 QRT1012 SCHEMATIC DIAGRAM, PCB CONNECTION DIAGRAM, PCB PARTS LIST

2DJM-750MK2
12 3 4
A
B
C
D
E
F
12 3 4
SAFETY INFORMATION
This service manual is intended for qualified service technicians; it is not meant for the casual do-it-
yourselfer. Qualified technicians have the necessary test equipment and tools, and have been trained
to properly and safely repair complex products such as those covered by this manual.
Improperly performed repairs can adversely affect the safety and reliability of the product and may
void the warranty. If you are not qualified to perform the repair of this product properly and safely, you
should not risk trying to do so and refer the repair to a qualified service technician.
CAUTION
Since the fuse may be in the neutral of the mains supply, disconnect the mains to de-energize the phase conductors.

3
DJM-750MK2
56 7 8
56 7 8
A
B
C
D
E
F
CONTENTS
SAFETY INFORMATION.......................................................................................................................................................... 2
1. SERVICE PRECAUTIONS .................................................................................................................................................... 4
1.1 NOTES ON SOLDERING ............................................................................................................................................... 4
1.2 NOTES ON REPLACING ............................................................................................................................................... 4
1.3 SERVICE NOTICE.......................................................................................................................................................... 4
2. SPECIFICATIONS................................................................................................................................................................. 6
2.1 ACCESORIES ................................................................................................................................................................ 6
2.2 SPECIFICATIONS .......................................................................................................................................................... 6
3. BASIC ITEMS FOR SERVICE .............................................................................................................................................. 7
3.1 CHECK POINTS AFTER SERVICING ........................................................................................................................... 7
3.2 JIGS LIST ....................................................................................................................................................................... 7
3.3 PCB LOCATIONS ......................................................................................................................................................... 10
4. BLOCK DIAGRAM .............................................................................................................................................................. 11
4.1 OVERALL WIRING DIAGRAM ..................................................................................................................................... 11
4.2 BLOCK DIAGRAM ........................................................................................................................................................ 12
4.3 POWER BLOCK DIAGRAM ......................................................................................................................................... 13
5. DIAGNOSIS ........................................................................................................................................................................ 14
5.1 STARTUP SEQUENCE ................................................................................................................................................ 14
5.2 TROUBLESHOOTING.................................................................................................................................................. 16
[0] Prior confirmation.................................................................................................................................................. 17
[1] Start Trouble ......................................................................................................................................................... 17
[2] Abnormality display............................................................................................................................................... 18
[3] AUDIO INPUT....................................................................................................................................................... 19
[4] AUDIO OUTPUT................................................................................................................................................... 20
[5] DVS....................................................................................................................................................................... 21
[6] OLED .................................................................................................................................................................... 22
[7] CROSS FADER .................................................................................................................................................... 22
[8] USBA .................................................................................................................................................................... 23
5.3 POWER SUPPLY DIAGNOSIS INFORMATION........................................................................................................... 24
5.4 CONFIRMATION OF EACH INTERFACE CONNECTION ........................................................................................... 25
6. SERVICE MODE ................................................................................................................................................................. 26
6.1 TEST MODE................................................................................................................................................................. 26
6.2 ABOUT THE DEVICE................................................................................................................................................... 38
7. DISASSEMBLY ................................................................................................................................................................... 39
8. EACH SETTING AND ADJUSTMENT ................................................................................................................................ 52
8.1 NECESSARY ITEMS TO BE NOTED........................................................................................................................... 52
8.2 UPDATING OF THE FIRMWARE ................................................................................................................................. 53
8.3 METHOD OF WRITING SERIAL NUMBER ................................................................................................................. 54
8.4 METHOD OF DVS CONNECTION CONFIRMATION................................................................................................... 55
8.5 ITEMS FOR WHICH USER SETTING ARE AVAILABLE ............................................................................................. 57
9. EXPLODED VIEWS AND PARTS LIST............................................................................................................................... 58
9.1 PACKING SECTION ..................................................................................................................................................... 58
9.2 EXTERIOR SECTION .................................................................................................................................................. 60
9.3 CHASSIS SECTION ..................................................................................................................................................... 62
9.4 CONTROL PANEL SECTION....................................................................................................................................... 64

3
DJM-750MK2
56 7 8
56 7 8
A
B
C
D
E
F
CONTENTS
SAFETY INFORMATION.......................................................................................................................................................... 2
10. SCHEMATIC DIAGRAM...................................................................................................................................................... 4
10.1 OVERALL WIRING DIAGRAM ..................................................................................................................................... 4
10.2 MAIN ASSY (1/11)........................................................................................................................................................ 5
10.3 MAIN ASSY (2/11)........................................................................................................................................................ 6
10.4 MAIN ASSY (3/11)........................................................................................................................................................ 7
10.5 MAIN ASSY (4/11)........................................................................................................................................................ 8
10.6 MAIN ASSY (5/11)........................................................................................................................................................ 9
10.7 MAIN ASSY (6/11)...................................................................................................................................................... 10
10.8 MAIN ASSY (7/11)...................................................................................................................................................... 11
10.9 MAIN ASSY (8/11)...................................................................................................................................................... 12
10.10 MAIN ASSY (9/11).................................................................................................................................................... 13
10.11 MAIN ASSY (10/11).................................................................................................................................................. 14
10.12 MAIN ASSY (11/11).................................................................................................................................................. 15
10.13 PNLA ASSY (1/3) ..................................................................................................................................................... 16
10.14 PNLA ASSY (2/3) ..................................................................................................................................................... 17
10.15 PNLA ASSY (3/3) ..................................................................................................................................................... 18
10.16 AINB ASSY (1/7) ...................................................................................................................................................... 19
10.17 AINB ASSY (2/7) ...................................................................................................................................................... 20
10.18 AINB ASSY (3/7) ...................................................................................................................................................... 21
10.19 AINB ASSY (4/7) ...................................................................................................................................................... 22
10.20 AINB ASSY (5/7) ...................................................................................................................................................... 23
10.21 AINB ASSY (6/7) ...................................................................................................................................................... 24
10.22 AINB ASSY (7/7) ...................................................................................................................................................... 25
10.23 USBA ASSY, MICB ASSY and MTRM ASSY ........................................................................................................... 26
10.24 HPJK ASSY and HPJM ASSY.................................................................................................................................. 27
10.25 OLED ASSY and CHFD ASSY................................................................................................................................. 28
10.26 BFXB ASSY, PWSB ASSY and HPVR ASSY........................................................................................................... 29
10.27 SW POWER SUPPLY and CRFD ASSY .................................................................................................................. 30
10.28 VOLTAGES / WAVEFORMS ..................................................................................................................................... 31
11. PCB CONNECTION DIAGRAM ........................................................................................................................................ 37
11.1 MAIN ASSY ................................................................................................................................................................ 37
11.2 PNLA ASSY................................................................................................................................................................ 39
11.3 AINB ASSY................................................................................................................................................................. 41
11.4 USBA, MICB, HPJK, HPJM, OLED and MTRM ASSYS............................................................................................. 43
11.5 CHFD, BFXB, PWSB, HPVR and CRFD ASSYS ....................................................................................................... 45
11.6 SW POWER SUPPLY................................................................................................................................................. 47
12. PCB PARTS LIST.............................................................................................................................................................. 48

4DJM-750MK2
12 3 4
A
B
C
D
E
F
12 3 4
1. SERVICE PRECAUTIONS
1.1 NOTES ON SOLDERING
1.2 NOTES ON REPLACING
1.3 SERVICE NOTICE
• For environmental protection, lead-free solder is used on the printed circuit boards mounted in this unit.
Be sure to use lead-free solder and a soldering iron that can meet specifications for use with lead-free solders for repairs
accompanied by reworking of soldering.
Do NOT use a soldering iron whose tip temperature cannot be controlled.
The part listed below is difficult to replace as a discrete component part.
It the failure of suspected that are listed in the table, replace whole ASSY.
ASSY Name Ref. No Parts No. Function Remarks
MAIN ASSY
IC1204 BD9328EFJ 12V =>1.25V DC/DC Converter IC with heat-pad
IC1205 TPS2557DRB Current Limit IC IC with heat-pad
IC1208NJM78M09DL1A 12V =>9V Regulator IC with heat-pad
IC1402 NJW4154GM1-A 12V =>-18V DC/DC Converter IC with heat-pad
IC1403BD9851EFV 12V =>±7.5V DC/DC Converter IC with heat-pad
IC1404 NJM78M15DL1A 18V =>15V Regulator IC with heat-pad
IC1405 NJM79M15DL1A -18V =>-15V Regulator IC with heat-pad
IC1406 NJM78M15DL1A 18V =>15V Regulator IC with heat-pad
IC1407 NJM79M15DL1A -18V =>-15V Regulator IC with heat-pad
IC1408NJM78M09DL1A 12V =>9V Regulator IC with heat-pad
IC1409 NJM78M15DL1A 18V =>15V Regulator IC with heat-pad
IC1410 UA78M05IKVURG39V =>5V Regulator IC with heat-pad
IC1411 UA78M33IKVUG39V =>3.3V Regulator IC with heat-pad
IC1412 UA78M05IKVURG39V =>5V Regulator IC with heat-pad
IC3001 D810K013DZKB400 DSPBGA
IC4001 AK4458VN DAC IC with heat-pad
Q46132SCR573DG Transistor Transistor with heat-pad
Q4614 2SAR573DG Transistor Transistor with heat-pad
Q4615 2SCR573DG Transistor Transistor with heat-pad
Q4616 2SAR573DG Transistor Transistor with heat-pad
AUDIO ASSY IC6001 AK5558VN ADC IC with heat-pad
This product is continuously monitoring abnormal voltages.
If abnormality is detected, power supply is immediately turned OFF.
Power supply abnormality is indicated by blinking the UTILITY(WAKE UP) LED
[cycle : 250 ms (lighting 125 ms/ light-off 125 ms)] .
UTILITY(WAKE UP) LED display other than the LED is lighting-off all, it will all be SW and VR free reaction.
Repair according to the diagnosis method of “5.3POWER SUPPLY DIAGNOSISINFORMATION.”
About voltage monitoring
This product includes user setting items. Check the settings before repairing.
Use the check sheet prepared in item 8.5 to transcribe the settings.
Setting contents are stored in the Flash ROM (IC2003) in the MAIN ASSY.
For confirming or changing setting contents, refer to “Changing the settings” of the Operationg Instructions.
Checking user setting contents
The contactless fader is mounted in the cross fader part of this product.
This has several times of durability comparing with conventional types.
As assembly of the fader part is required high precision, service parts are provided only as an assembly
(Part name is CROSS FADER ASSY (DXA2257)).
After replacing the part, make sure to acquire and save the maximum and minimum A/D values of [Cross fader setting
mode (CFDR SET)] in the test mode.
If this calibration is not conducted, normal start is not possible.
If MAIN ASSY is replaced, make sure to acquire and save the maximum and minimum A/D values of [Cross fader setting
mode (CFDR SET)] after the replacement.
About the replacing CROSS FADER ASSY
Display part of this product employs OLED. Exchange at the time of OLED failure, replace using OLED ASSY (DEA1065).
Matrix OEL is stick to Holder using double side tape. If trying to peel in the case of failing to paste,
fault will be caused due to the stress.
Service part supplies as ASSY who stuck Matrix OEL and Holder.
About the replacing OLED ASSY
C4638 and C4639 in the MAIN ASSY are locked with bond to prevent solder cracks caused by fall or vibration.
When any of them is replaced for repair, it must be locked with bond after the replacement.
Silicon Bond: GYA 1011
About the replacing Capacitor (C4638, C4639)

5
DJM-750MK2
56 7 8
56 7 8
A
B
C
D
E
F
Checking
LEDs
No polarity
C4 C5
Primary side of SW POWER SUPPLY remains voltage long time and the primary solder side can be seen.
So if you touch the primary solder side, it is possible to receive an electrical shock.
There is the red area below where you tend to receive an electrical shock.
Be sure to discharge the voltage of primary side to avoid receiving the electrical shock.
When discharging the above point, use the following discarge jig as needed.
While the charging voltage is left of both C4 and C5, either of checking LEDs turns on.
And if both of LED turns off, you can avoid receiving the electrical shock!!
DWR1548 (SW POWER SUPPLY) Primary side electrical shock
When replacing the Control Panel, replace using Control Panel (Service ASSY) : DEA1077
Control Panel supplies as Service ASSY who stuck Packing and double side tape for Lens because precision is
necessary of sticking of them.
About the replacing Control Panel
Electrical shock area of A-side.
Electrical shock area of B-side.
Circuit of "discharge JIG" is shown below.
• Resister is all 10kΩ(3W)
• Both of LED is LTL17KRH5D
When there is no above type LED, take measures the
following method.
• Step1: After the power is turned off,wait 2 minutes.
• Step2: Connect the Register Jig and leave the unit
as it is, for 10 seconds.

6DJM-750MK2
12 3 4
A
B
C
D
E
F
12 3 4
2. SPECIFICATIONS
2.1 ACCESORIES
2.2 SPECIFICATIONS
•Power cord (LSYXJ : ADG1244)
(UXJCB : DDG1108)
(XJCN : DDG1114)
•USB cable (DDE1128)
(XJCN : DRH1436)
• Operating instructions
(Quick start guide)
(LSYXJ : DRH1433)
(LSYXJ : DRY1270)
(UXJCB : DRH1434)
• License key card
(rekordbox dj, recordbox dvs)
• Warranty card*
*
The corresponding information is provided on the last page (UXJCB model).
Cautions
The license key cannot be reissured. Be careful not to losted it.
General – Main Unit
Power requirements............................. AC 110 V to 240 V, 50 Hz/60 Hz
Power consumption........................................................................ 40 W
Power consumption (standby)........................................................ 0.3W
Main unit weight ............................................................... 6.6 kg (14.6 lb)
Max. dimensions............... 320 mm (W) × 107.9 mm (H) × 387.9 mm (D)
(12.6 in. (W) × 4.2 in. (H) × 15.3in. (D))
Tolerable operating temperature........ +5 °C to +35 °C (+41 °F to +95 °F)
Tolerable operating humidity.................... 5 % to 85% (no condensation)
Audio Section
Sampling rate............................................................................... 48kHz
D/A converter................................................................................. 32-bit
Channel input A/D converter .......................................................... 32-bit
Other A/D converter ....................................................................... 24-bit
Frequency characteristic
LINE ......................................................................... 20 Hz to 20 kHz
S/N ratio (rated output)
PHONO.................................................................................... 87 dB
LINE .......................................................................................105 dB
MIC .......................................................................................... 79 dB
Total harmonic distortion (LINE— MASTER1)............................ 0.005 %
Standard input level / Input impedance
PHONO...................................................................... –52 dBu/47 kΩ
LINE.......................................................................... –12 dBu/47 kΩ
MIC .............................................................................. –57dBu/3kΩ
RETURN.................................................................... –12 dBu/47 kΩ
Standard output level / Load impedance / Output impedance
MASTER1........................................................ + 6 dBu/10 kΩ/300 Ω
MASTER2........................................................ + 2 dBu/10 kΩ/680 Ω
BOOTH............................................................ + 6 dBu/10 kΩ/300 Ω
SEND(when RETURN TYPE is "AUX").............. –6 dBu/10 kΩ/680 Ω
SEND(when RETURN TYPE is "INSERT")....... –12dBu/10 kΩ/680 Ω
PHONES.................................................. + 8dBu/32 Ω/10 Ωor less
Rated output level / Load impedance
MASTER1................................................................. +25 dBu/10 kΩ
MASTER2................................................................. +21 dBu/10 kΩ
Crosstalk (LINE)............................................................................ 82 dB
Channel equalizer characteristic
HI ............................................................... –26 dB to +6 dB (20 kHz)
MID .............................................................. –26 dB to +6 dB (1 kHz)
LOW ............................................................ –26 dB to +6 dB (20 Hz)
Microphone equalizer characteristic
HI ............................................................. –12 dB to +12 dB (10 kHz)
LOW ........................................................ –12 dB to +12 dB (100 Hz)
Input / Output terminals
PHONO input terminal
RCA pin jacks...........................................................................4 sets
LINE input terminal
RCA pin jacks...........................................................................4 sets
MIC input terminal (XLR/TRS)
XLR connector & 1/4” TRSjack..................................................1 set
RETURN Input terminals (TS)
1/4” TSjack................................................................................1 set
MASTER output terminal
XLR connector........................................................................... 1 set
RCA pin jacks ............................................................................ 1 set
BOOTH output terminal
1/4” TRSjack .............................................................................1 set
SEND output terminal (TS)
1/4” TSjack................................................................................1 set
PHONESoutput terminal
1/4” stereo phone jack ............................................................... 1 set
3.5mm stereo mini jack ............................................................ 1 set
USB terminal
Type A....................................................................................... 1 set
Power supply...5 V/2.1 A or less
B type ........................................................................................ 1 set
The specifications and design of this product are subject to change
without notice.
•

7
DJM-750MK2
56 7 8
56 7 8
A
B
C
D
E
F
3. BASIC ITEMS FOR SERVICE
3.1 CHECK POINTS AFTER SERVICING
3.2 JIGS LIST
1 Check the firmware version in Test mode. The version of the firmware must be latest.
Update firmware to the latest one, if it is not the latest.
2Confirm whether the customer complain has
been solved. If the problem pointed out by the
customer occurs with a specific source or
operation, input that specific source then perform
that specific operation for checking.
The customer complain must not be reappeared.
Audio and operations must be normal.
3Check the analog audio input (each channel, MIC,
RETURN).
( CDJ player, analog player and MIC to analog
connection )
Audio and operations must be normal.
4 Check the analog audio output (MASTER 1/2,
BOOTH, SEND)( CDJ player to analog connection)
Audio and operations must be normal.
6 Check the each operation (KEY, SW, VR, fader,
etc.) and indicator.
That it works properly in Test mode check.
8Check the DVS.PC application is operating normally, audio and operations must be normal of
each channel.
9 Check the user settings. It is in the contents before repairs.
7 Check the connection of each interface
USB A terminal
USB B terminal
5Check the headphone output (1/4” jack, mini jack). Noise and audio must be normal.
10 Check the appearance of the product. No scratches or dirt on its appearance after receiving it for service.
To keep the product quality after servicing, confirm recommended check points shown below.
Distortion
Noise
Volume too low
Volume too high
Volume fluctuating
Sound interrupted
See the table below for the items to be checked regarding audio.
Item to be checked regarding audio
No. Procedure Check points
Check the lighting of USB connection indicator by inserting a USB memory.
It is properly recognized in PC.
Jigs List
Jig Name Part No. Purpose of use / Remarks
USB cable GGP1193For PC connection, Accessories
Serial number writing software GGS1198Used in the writing of serial number to be performed
after the MAIN ASSY replacement.
Refer to “ 8.3METHOD OF WRITING SERIAL
NUMBER ”.
License-key card for Service GGP1522
GGP1523
For activation of rekordbox dj
For activation of rekordbox DVS
Lubricants List
Name Lubricants No. Remarks
Sillcon Bond GYA1011 Used to do bond locking of C4638 and C4639 in the
MAIN ASSY.

8DJM-750MK2
12 3 4
A
B
C
D
E
F
12 3 4
SEVICE CHECK SHEET
TEST MODE
MODE CHECK
CONTENTS OPERATIION POINT MODDE TITLE INDICATION POINT STATE CHECK
Version Version OLED SYSTEM Ver.
SH-B Ver.
SH-A Ver.
BOOT Ver.
PANEL Ver.
PANEL-B Ver.
DSP P Ver.
DSP D Ver.
LED all light-OFF ALL CLEAR OLED About 1 second indication (at the start of mode)
LED all light-ON ALL SET All LED, OLED "ALL SET" indication for about 1 second
(all LEDs light-ON, OLED mode is started)
KEY operation KEY TESTOLED
DUB ECHO LED / OLED Light-ON when KEY is pressed / "CFX 1" indication
SWEEP LED / OLED Light-ON when KEY is pressed / "CFX 2" indication
NOISE LED / OLED Light-ON when KEY is pressed / "CFX 3" indication
FILTER LED / OLED Light-ON when KEY is pressed / "CFX 4" indication
CUE CH1 LED / OLED Light-ON when KEY is pressed / "CUE 1" indication
CUE CH2 LED / OLED Light-ON when KEY is pressed / "CUE 2" indication
CUE CH3LED / OLED Light-ON when KEY is pressed / "CUE 3" indication
CUE CH4 LED / OLED Light-ON when KEY is pressed / "CUE 4" indication
CUE MASTER LED / OLED Light-ON when KEY is pressed / "CUE MST" indication
SEND/RETURN ON/OFF LED / OLED Light-ON when KEY is pressed / "S/R ON" indication
BEAT DOWN ( ) No LED / OLED — / "BEAT <" indication
BEAT UP ( ) No LED / OLED — / "BEAT >" indication
TAP No LED / No OLED Because it is used for mode transition
AUTO/TAP No LED / OLED — / "AUTO" indication
UTILITY LED / OLED Light-ON when KEY is pressed / "UTILITY" indication
FX FREQUENCY LOW LED / OLED Light-ON when KEY is pressed / "FREQ L" indication
FX FREQUENCY MID LED / OLED Light-ON when KEY is pressed / "FREQ M" indication
FX FREQUENCY HI LED / OLED Light-ON when KEY is pressed / "FREQ H" indication
EFFECT ON/OFF LED / OLED Light-ON when KEY is pressed / "EFX ON" indication
SW operation SW TESTOLED
INPUT SELECT CH1 USB CH1 Level Meter LED [12dB] light-ON
LINE [9dB] light-ON
PHONO [6dB] light-ON
RETURN AUX [3dB] light-ON
INPUT SELECT CH2 USB CH2 Level Meter LED [12dB] light-ON
LINE [9dB] light-ON
PHONO [6dB] light-ON
RETURN AUX [3dB] light-ON
INPUT SELECT CH3USBCH3Level Meter LED [12dB] light-ON
LINE [9dB] light-ON
PHONO [6dB] light-ON
RETURN AUX [3dB] light-ON
INPUT SELECT CH4 USB CH4 Level Meter LED [12dB] light-ON
LINE [9dB] light-ON
PHONO [6dB] light-ON
RETURN AUX [3dB] light-ON
CH FADER Assign CH1 Assign A CH1 Level Meter LED [–24dB] light-ON
THRU [–18dB] light-ON
Assign B [–12dB] light-ON
CH FADER Assign CH2 Assign A CH2 Level Meter LED [–24dB] light-ON
THRU [–18dB] light-ON
Assign B [–12dB] light-ON
CH FADER Assign CH3Assign A CH3Level Meter LED [–24dB] light-ON
THRU [–18dB] light-ON
Assign B [–12dB] light-ON
CH FADER Assign CH4 Assign A CH4 Level Meter LED [–24dB] light-ON
THRU [–18dB] light-ON
Assign B [–12dB] light-ON
MIC OFF CH1 Level Meter LED [0dB] light-ON
ON [–3dB] light-ON
TALK OVER [–6 dB ] light- ON
HEAD PHONESMONO SPLIT CH2 Level Meter LED [–6dB] light-ON
STEREO [–9dB] light-ON
SND/RTN RETURN IN 1/4"TSJACK Master Level Meter Lch LED [15dB] light-ON
USB Master Level Meter [CLIP] light-ON
SND/RTN TYPE AUX Master Level Meter Lch LED [12dB] light-ON
INSERT [9dB] light-ON
EQ CURVE ISOLATOR CH2 Level Meter LED [0dB] light-ON
EQ [–3dB] light-ON
CH FADER CURVE Left CH3Level Meter LED [0dB] light-ON
MID [–3dB] light-ON
Right [–6dB] light-ON
CROSS FADER CURVE Left CH4 Level Meter LED [0dB] light-ON
MID [–3dB] light-ON
Right [–6dB] light-ON
Channel Select SW CF.B Master Level Meter Lch LED [–24dB] light-ON
CF.A [–15dB] light-ON
MIC [–9dB] light-ON
1[–6dB]light-ON
2[–3dB] light-ON
3[0dB] light-ON
4[3dB] light-ON
MASTER [6dB] light-ON
Effect Select SW DELAY Master Level Meter Lch LED [–24dB] light-ON
ECHO [–15dB] light-ON
PING PONG [–9dB] light-ON
SPIRAL [–6dB] light-ON
REVERB [–3dB] light-ON
TRANS[0dB] light-ON
FLANGER [3dB] light-ON
PITCH [6dB] light-ON
ROLL [9dB] light-ON
VINYL BRAKE [12dB] light-ON
HELIX [15dB] light-ON

9
DJM-750MK2
56 7 8
56 7 8
A
B
C
D
E
F
TEST MODE
MODE CHECK
CONTENTS OPERATIION POINT MODDE TITLE INDICATION POINT STATE CHECK
Volume operation VOL TESTOLED
Group 1
CH1 TRIM CH1 Level Meter LED "– " : Lights OFF — "+9" : Full Illuminate
CH2 TRIM CH2 Level Meter LED "– " : Lights OFF — "+9" : Full Illuminate
CH3TRIM CH3Level Meter LED "– " : Lights OFF — "+9" : Full Illuminate
CH4 TRIM CH4 Level Meter LED "– " : Lights OFF — "+9" : Full Illuminate
MIC HI Master Level Meter Lch LED "–12 " : Lights OFF — "+12" : Full Illuminate
MIC LOW Master Level Meter Rch LED "–12 " : Lights OFF — "+12" : Full Illuminate
Group 2
CH1 HI CH1 Level Meter LED "–26/– " : Lights OFF — "+6" : Full Illuminate
CH2 HI CH2 Level Meter LED "–26/– " : Lights OFF — "+6" : Full Illuminate
CH3HI CH3Level Meter LED "–26/– " : Lights OFF — "+6" : Full Illuminate
CH4 HI CH4 Level Meter LED "–26/– " : Lights OFF — "+6" : Full Illuminate
CFX PARAMETER Master Level Meter Lch LED "MIN" : Lights OFF — "MAX" : Full Illuminate
HEAD PHONESMIXING Master Level Meter Rch LED "CUE" : Lights OFF — "MASTER" : Full Illuminate
Group 3
CH1 MID CH1 Level Meter LED "–26/– " : Lights OFF — "+6" : Full Illuminate
CH2 MID CH2 Level Meter LED "–26/– " : Lights OFF — "+6" : Full Illuminate
CH3MID CH3Level Meter LED "–26/– " : Lights OFF — "+6" : Full Illuminate
CH4 MID CH4 Level Meter LED "–26/– " : Lights OFF — "+6" : Full Illuminate
HEAD PHONESLEVEL Master Level Meter Lch LED "– " : Lights OFF — "0" : Full Illuminate
EFFECT LEVEL/DEPTH Master Level Meter Rch LED "MIN" : Lights OFF — "MAX" : Full Illuminate
Group 4
CH1 LOW CH1 Level Meter LED "–26/– " : Lights OFF — "+6" : Full Illuminate
CH2 LOW CH2 Level Meter LED "–26/– " : Lights OFF — "+6" : Full Illuminate
CH3LOW CH3Level Meter LED "–26/– " : Lights OFF — "+6" : Full Illuminate
CH4 LOW CH4 Level Meter LED "–26/– " : Lights OFF — "+6" : Full Illuminate
MASTER LEVEL Master Level Meter Lch LED "– " : Lights OFF — "0" : Full Illuminate
BOOTH MONITOR Master Level Meter Rch LED "– " : Lights OFF — "0" : Full Illuminate
Group 5
CH1 COLOR CH1 Level Meter LED "LOW" : Lights OFF — "HI" : Full Illuminate
CH2 COLOR CH2 Level Meter LED "LOW" : Lights OFF — "HI" : Full Illuminate
CH3COLOR CH3Level Meter LED "LOW" : Lights OFF — "HI" : Full Illuminate
CH4 COLOR CH4 Level Meter LED "LOW" : Lights OFF — "HI" : Full Illuminate
SND/RTN LEVEL Master Level Meter Lch LED "MIN" : Lights OFF — "MAX" : Full Illuminate
Fader operation FDR TESTOLED
CH1 FADER CH1 Level Meter LED "0" : Lights OFF — "10" : Full Illuminate
CH2 FADER CH2 Level Meter LED "0" : Lights OFF — "10" : Full Illuminate
CH3FADER CH3Level Meter LED "0" : Lights OFF — "10" : Full Illuminate
CH4 FADER CH4 Level Meter LED "0" : Lights OFF — "10" : Full Illuminate
CROSS FADER Master Level Meter Lch LED "A" : Lights OFF — "B" : Full Illuminate
Level Meter
indication
LED TESTOLED
CH1 CUE CH1 Level Meter Press CUE light-ON one by one from the bottom (pressed 11 times)
CH2 CUE CH2 Level Meter Press CUE light-ON one by one from the bottom (pressed 11 times)
CH3CUE CH3Level Meter Press CUE light-ON one by one from the bottom (pressed 11 times)
CH4 CUE CH4 Level Meter Press CUE light-ON one by one from the bottom (pressed 11 times)
MASTER CUE Master Level Meter Lch LED Press CUE light-ON one by one from the bottom (pressed 11 times)
FREQUENCY LOW Master Level Meter Rch LED + CLIP LED Press CUE light-ON one by one from the bottom (pressed 12 times)
Device check DEVICE OLED
DSP SDRAM SDRAM OLED CHK
OK
NG
UPDATE PORT UPDPORT OLED CHK
OK
NG
UPDATE PORT NG CH1 Level Meter PNL_MODE : [–24dB] light-ON
A-PNL_MOSI : [–18dB] light-ON
A-PNL_MISO : [–12dB] light-ON
A-PNL_CLK : [–9dB] light-ON
A-PNL_CTRL : [–6dB] light-ON
A-PNL_INT : [–3dB] light-ON

10 DJM-750MK2
12 3 4
A
B
C
D
E
F
12 3 4
3.3 PCB LOCATIONS
MAIN ASSY
A
SW POWER SUPPLY
N
HPJK ASSY
F
CRFD ASSY
O
BFXB ASSY
J
Cross Fader ASSY
(DXA2257)
HPJM ASSY
G
L
PNLA ASSY
B
AINB ASSY
C
MICB ASSY
E
MTRM ASSY
K
HPVR ASSY
M
CHFD ASSY
I
• Control Panel Section • Chassis Section
Front
(Top view)(Bottom view)
OLED ASSY
H
PWSB ASSY
USBA ASSY
D
OLED ASSY
(DEA1065)
NOTES: Parts marked by “NSP” are generally unavailable because they are not in our Master Spare Parts List.
The mark found on some component parts indicates the importance of the safety factor of the part.
Therefore, when replacing, be sure to use parts of identical designation.
Mark No. Description Part No.
LIST OF ASSEMBLIES
NSP 1..MOTHER ASSY DWM2653
2..MAIN ASSY DWX3997
2..USBA ASSY DWX3998
2..OLED ASSY DWX4010
NSP 1..AUDIO ASSY DWM2654
2..AINB ASSY DWX3999
2..MICB ASSY DWX4000
2..HPJK ASSY DWX4001
2..HPJM ASSY DWX4002
1..PNLA ASSY DWX3996
NSP 1..SUB ASSY DWM2655
2..CHFD ASSY DWX4003
2..BFXB ASSY DWX4004
2..MTRM ASSY DWX4005
2..PWSB ASSY DWX4006
2..HPVR ASSY DWX4007
1..SW POWER SUPPLY DWR1548
NSP 1..CRFD ASSY DWX3258
Mark No. Description Part No.

11
DJM-750MK2
56 7 8
56 7 8
A B C
D
E
F
4. BLOCK DIAGRAM 4.1 OVERALL WIRING DIAGRAM
!
!
CN1802
CKS6476-
1
NC
2
OLED1_VKH
3
V+15OLED
4
V+3R3OLED
5
V+3R3OLED
6
OLED_RST
7
OLED_CS
8
OLED_ADDR
9
OLED_CLK
10
OLED_MOSI
11
GNDD
12
GNDD
CN4001
AKM1274-
1
GNDREF
2
AD_CRS_FADER
3
V+3R3REF
CN1003
CKS3870-
1
V+3R3_REF_L
2
CH1_FD
3
CH2_FD
4
CH3_FD
5
CH4_FD
6
CRS_FD
7
GND_REF_L
8
GNDD
9
B-PNL_INT
10
A-PNL_INT
11
B-PNL_CTRL
12
A-PNL_CTRL
13
V+5E
14
GNDD
15
B-PNL_MISO
16
GNDD
17
B-PNL_CLK
18
GNDD
19
B-PNL_MOSI
20
GNDD
21
GNDD
22
A-PNL_MISO
23
GNDD
24
A-PNL_MOSI
25
GNDD
26
A-PNL_CLK
27
GNDD
28
GND_REF
29
V+3R3REF
CN1002
CKS3865-
1
GNDD
2
V+1R25D_CONT
3
VA_CONT
4
PWR_ON
5
CPU_MUTE
6
V+3R3D_CONT
7
PNL_MODE
8
FAULT_DET
9
B_RST
10
ACOFF_DET
11
MVR_MUTE
12
PWR_SW
13
GND_OLED
14
GNDD_LED
15
V+3R3OLED
16
GNDD_LED
17
V+15OLED
18
GNDD_LED
19
GND_OLED
20
GNDD_LED
21
V+5LED
22
V+9LED
23
V+5LED
24
V+9LED
CN1004
VKN2050-
1
ADAT_MIC
2
GNDD
3
ADAT_CH1
4
GNDD
5
CH1_SEL
6
GNDD
7
ADAT_CH2
8
GNDD
9
CH2_SEL
10
GNDD
11
MCLK_ADC
12
GNDD
13
BICK_ADC
14
GNDD
15
LRCK_ADC
16
GNDD
17
V+3R3D_CLK
18
V+3R3D_CLK
19
GNDD
20
GNDD
21
xRST_ADC
22
GNDD
23
ADAT_CH3
24
GNDD
25
CH3_SEL
26
GNDD
27
ADAT_CH4
28
GNDD
29
CH4_SEL
30
GNDD
31
ADAT_RETURN
32
GNDD
33
RTN_IN
34
GNDD
35
B_ADDA_SDA
36
GNDD
37
B_ADDA_SCL
38
GNDD
39
GNDD
40
GNDD
CN1005
AKM1281-
1
GNDA
2
V-15A_IN
3
GNDA
4
V+15A_IN
5
GNDA
6
GNDA
7
V+5A
8
GNDA
9
V+3R3A
10
GNDA
CN1006
AKM1274-
1
GNDD
2
PWR_SW
3
GNDD
CN4601
KM200NA3E
1
HP_Lmini
2
GNDA_HP
3
HP_Rmini
CN4602
KM200NA3
1
HP_L
2
GNDA_HP
3
HP_R
CN2502
AKM1281-
1
GNDF_USBC
2
USBC_DP
3
USBC_DM
4
GNDD_USBC
5
GNDD_USBC
6
V+5R2D_VBUS
7
V+5R2D_VBUS
8
V+5R2D_VBUS
9
GNDD_USBC
10
GNDD_USBC
CN5001
VKN1811-
1
GNDD
2
GNDD
3
GNDD
4
B_ADDA_SCL
5
GNDD
6
B_ADDA_SDA
7
GNDD
8
RTN_IN
9
GNDD
10
ADAT_RETURN
11
GNDD
12
CH4_SEL
13
GNDD
14
ADAT_CH4
15
GNDD
16
CH3_SEL
17
GNDD
18
ADAT_CH3
19
GNDD
20
xRST_ADC
21
GNDD
22
GNDD
23
V+3R3D_CLK
24
V+3R3D_CLK
25
GNDD
26
LRCK_ADC
27
GNDD
28
BICK_ADC
29
GNDD
30
MCLK_ADC
31
GNDD
32
CH2_SEL
33
GNDD
34
ADAT_CH2
35
GNDD
36 CH1_SEL 37 GNDD 38 ADAT_CH1 39GNDD 40 ADAT_MIC
KM200NA10L
CN5002
1
GNDA
2
V-15A_IN
3
GNDA
4
V+15A_IN
5
GNDA
6
GNDA
7
V+5A
8
GNDA
9
V+3R3A
10
GNDA
13P-1.25FJ
CN5003
1
GNDA_MIC
2
GNDA_MIC
3
GNDA_MIC
4
GNDA_MIC
5
GNDA_MIC
6
V-15A_IN
7
GNDA_MIC
8
V+15A_IN
9
GNDA_MIC
10
GNDA_MIC
11
GNDA_MIC
12
MIC_ADC_IN
13
GNDA_MIC
13R-1.25FJ
CN6502
1
GNDA_MIC
2
GNDA_MIC
3
GNDA_MIC
4
GNDA_MIC
5
GNDA_MIC
6
V-15A_IN
7
GNDA_MIC
8
V+15A_IN
9
GNDA_MIC
10
GNDA_MIC
11
GNDA_MIC
12
MIC_ADC_IN
13
GNDA_MIC
CN6501
AKM7101-
1
GNDA_MIC
2
MIC_TRIM_OUT
3
GNDA_MIC
4
GNDA_MIC
5
GNDA_MIC
6
GNDA_MIC
7
GNDA_MIC
8
GNDA_MIC
9
GNDA_MIC
10
MIC_TRIM_IN
11
GNDA_MIC
CN6601
KM200NA3L
1
HP_L
2
GNDA_HP
3
HP_R
CN6701
KM200NA3LE
1
HP_Lmini
2
GNDA_HP
3
HP_Rmini
CN7901
AKN7067-
1
GNDA_MIC
2
MIC_TRIM_OUT
3
GNDA_MIC
4
GNDA_MIC
5
GNDA_MIC
6
GNDA_MIC
7
GNDA_MIC
8
GNDA_MIC
9
GNDA_MIC
10
MIC_TRIM_IN
11
GNDA_MIC
CN1801
CKS3852-
1
OLED_XCS
2
OLED_ADDR
3
GNDD
4
OLED_MOSI
5
GNDD
6
OLED_CLK
7
GNDD
8
OLED_RST
9
GNDD
10
V+3R3OLED
11
V+15OLED
CN8901
KM200NA3
1
2
3
CN1601
AKM1281-
1
GNDF_USBC
2
USBC_DP
3
USBC_DM
4
GNDD_USBC
5
GNDD_USBC
6
V+5R2D_VBUS
7
V+5R2D_VBUS
8
V+5R2D_VBUS
9
GNDD_USBC
10
GNDD_USBC
CN7008
VKN1255-
1
V+9LED
2
V+5LED
3
V+9LED
4
V+5LED
5
GNDD_LED
6
GND_OLED
7
GNDD_LED
8
V+15OLED
9
GNDD_LED
10
V+3R3D_OLED
11
GNDD_LED
12
GND_OLED
13
POWER_SW
14
MVR_MUTE
15
ACOFF_DET
16
SHB_RST
17
FAULT_DET
18
M16_PNL_MODE
19
V+3R3D_CONT
20
CPU_MUTE
21
V+12SW_CONT
22
V+12A_CONT
23
V+1R25D_CONT
24
GNDD
CN7004
VKN1242-
1
OLED_xCS
2
OLED_ADDR
3
GNDD_OLED
4
OLED_MOSI
5
GNDD_OLED
6
OLED_SCL
7
GNDD_OLED
8
OLED_xRST
9
GNDD_OLED
10
V+3R3D_OLED
11
V+15OLED1
CN7602
KM200NA3L
1
GNDD_REF_L
2
CRS_FADER
3
V+3R3D_REF_L
CN7006
VKN1260-
1
V+3R3REF
2
GNDD_REF
3
GNDD
4
SHA_M16_CLK
5
GNDD
6
SHA_M16_MOSI
7
GNDD
8
SHA_M16_MISO
9
GNDD
10
GNDD
11
SHB_M16_MOSI
12
GNDD
13
SHB_M16_CLK
14
GNDD
15
SHB_M16_MISO
16
GNDD
17
V+5E
18
SHA_M16_CTRL
19
SHB_M16_CTRL
20
SHA_M16_INT
21
SHB_M16_INT
22
GNDD
23
GNDD_REF_L
24
CRS_FD
25
CH4_FADER
26
CH3_FADER
27
CH2_FADER
28
CH1_FADER
29
V+3R3D_REF_L
CN7001
VKN1237-
1
V+3R3D_REF_L
2
HP_LEVEL
3
HP_MIX
4
GNDD_REF_L
5
KEY_SEG6_PNL
6
KEY_GRID3
CN7012
VKN1248-
1
V+3R3D_REF_L
2
CH1_FADER
3
CH2_FADER
4
CH3_FADER
5
CH4_FADER
6
CROSS_FADER
7
GNDD_REF_L
8
KEY_GRID0
9
KEY_GRID1
10
KEY_GRID2
11
KEY_GRID3
12
KEY_GRID4
13
KEY_GRID5
14
KEY_SEG3_PNL
15
KEY_SEG4_PNL
16
KEY_SEG5_PNL
17
GNDD_REF_L
CN7003
VKN1250-
1
GNDD
2
KEY_SEG8_PNL
3
KEY_SEG6_PNL
4
KEY_SEG5_PNL
5
KEY_SEG4_PNL
6
KEY_SEG3_PNL
7
KEY_GRID7
8
KEY_GRID3
9
GNDD
10
TIME_ENC_0
11
TIME_ENC_1
12
GNDD_REF_L
13
GNDD_REF_L
14
BFX_LEVELDEPTH
15
BFX_CH_SEL
16
V+3R3D_REF_L
17
LED_SEG7
18
LED_GRID0_BFXB
19
GNDD_LED
CN7701
VKN1279-
1
GNDD
2
KEY_SEG8_PNL
3
KEY_SEG6_PNL
4
KEY_SEG5_PNL
5
KEY_SEG4_PNL
6
KEY_SEG3_PNL
7
KEY_GRID7
8
KEY_GRID3
9
GNDD
10
TIME_ENC_0
11
TIME_ENC_1
12
GNDD_REF_L
13
GNDD_REF_L
14
BFX_LEVELDEPTH
15
BFX_CH_SEL
16
V+3R3D_REF_L
17
LED_SEG7
18
LED_GRID0_BFX
19
GNDD_LED
CN7601
VKN1248-
1
GNDD_REF_L2
2
KEY_SEG5_PNL
3
KEY_SEG4_PNL
4
KEY_SEG3_PNL
5
KEY_GRID5
6
KEY_GRID4
7
KEY_GRID3
8
KEY_GRID2
9
KEY_GRID1
10
KEY_GRID0
11
GNDD_REF_L1
12
CRS_FADER
13
CH4_FADER
14
CH3_FADER
15
CH2_FADER
16
CH1_FADER
17
V+3R3D_REF_L
CN8101
VKN1237-
1
KEY_GRID3
2
KEY_SEG5_PNL
3
GNDD_REF_L
4
HP_MIX
5
HP_LEVEL
6
V+3R3D_REF_L
USB B
HP
LR
(TS)
JA5901 JA5902
RETURN
DKN1654- DKN1652-
LR
JA4601 JA4602
SEND
DKN1652- DKN1652-
(TS)
PHONO
DKB1090-
LINE
CH1 CH2 CH3CH4
L
R
JA5101
(XLR/TRS)
DKB1090-
JA5301
DKB1090-
JA5501
DKB1090-
JA5701
MIC
DKN1622-
JA6601
PHONES
JA2001
DKN1237-
JA1601
DKB1118-
LR L
JA4201
DKB1093-
R
MASTER1
JA4203
MASTER2
JA4402JA4401
BOOTH
DKB1120-
DKN1653- DKN1653-
(TRS)
LR
JA4202
DKB1093-
XKN3017-
HPmini
JA6701
MXS4057-
JA6501
DKB1124-
1/4 PHONE
L
R
L
R
L
R
PHONO PHONO
LINE LINE
PHONO
LINE
designation.
with same parts (safety regulation authorized) of identical
mark found on some component parts should be replacedThe
( )
(A-TYPE)
USB CONNECTOR
L=125mmPF03PP-B12
1mm pitch
FFC REVERSE
L=45mm
DDD1810-
B to B
L=135mm
DDA1079-
L=100mm
PF10PP-S10
L=90mm
DDD1550-
FFC SAME
0.5m m pitch
B to B
1mm pitch
FFC SAME
L=245mm
DDD1805-
1mm pitch
FFC SAME
L=325mm
DDD1806-
105
L=50mm
PF03PP-B05
L=190mm
DDD1808-
FFC SAME
1mm pitch
DDD1809-
1mm pitch
L=205mmFFC REVERSE
FFC SAME
L=50mm
DDD1807- L=100mmPF03PP6B10 L=125mmPF03PP-B12
CN1001
DKN1666-
CN2
V+12 V+12 V+12
V+12A
V+12E
GNDA GNDA
GNDD GNDD
standby
V+12 V+12 V+12 V+12A V+12E GNDA GNDA GNDD GNDD standby
! !
L
N
CN1
!
LIVE
NEUTRAL
L=183mm
DDC1025-
L=190mm
DKP3988-
1 2 3 4 5 6 7 8 9
10
1 2 3 4 5 6 7 8 9
10
A
A A
1/11- 11/11
MAIN ASSY
(DWX3997)
FHPJK ASSY
(DWX4001)
DUSBA ASSY
(DWX3998)
EMICB ASSY
(DWX4000)
GHPJM ASSY
(DWX4002)
ICHFD ASSY
(DWX4003)
HOLED ASSY
(DWX4010)
JBFXB ASSY
(DWX4004)
KMTRM ASSY
(DWX4005)
B B B
1/3- 3/3
PNLA ASSY
(DWX3996)
AINB ASSY
(DWX3999)
LPWSB ASSY
(DWX4006)
MHPVR ASSY
(DWX4007)
NSW POWER SUPPLY
(DWR1548)
OCRFD ASSY
(DWX3258)
C
C C
1/7- 7/7
4. BLOCK DIAGRAM
CRFD ASSY because only ASSY replacement,
PCB CONNECTION DIAGRAM is not mentioned.

12 DJM-750MK2
12 3 4
A
B
C
D
E
F
12 3 4
4.2 BLOCK DIAGRAM
IC3001
DSP
D810K013DZKB400
McASP1
McASP1
IC6001
ADC
AK5558VN
IC5903
ADC
IC4001
DAC
AK4458VN
IC3003
EMIF(B)
McASP0 UHPI(S)
McASP2
IC2501
USBA UCOM
R5S72690RW266FP
USB
IC1205
USB-A HSSW
TPS2557DRB
USB-A
IC2505
MFi IC
H337S3959
SPI(M)
SPI(S)
IC2003
FLASH(16Mb)
GPIOI2C
IC2004
74LCX244FT
SSI0
IC2001
USBB UCOM
R5S72690RW266FP
USB-B
USB
BSC(M) SSI0
SPI(M)
SPI(M)
IC7001
PANEL UCOM
R5F364AENFA-U0
SPI(S)
SPI(S)
SPI(M)
SPI(S)
LED
KEY
VR
OLED
CRS/CH
FADER
IC5904
ADC
Other control
A/D
SPI(M)
GPIO
GPIO
McASP1
16bit
HPI 16bit
HPI 16bit
AD
MUTE
STBY
etc...
LINE
PHONO
CH1
LINE
PHONO
CH2
LINE
PHONO
CH3
LINE
PHONO
CH4
MIC
RETURN
MASTER1
MASTER2
BOOTH
SEND
HP
HP_mini
USB
36
37
32
33
42
43
38
39
28
29
22
23
17
18
21
22
9
10
11
12
3
4
7
8
59
60
63
64
38
39
37
36
1
2
9
2 9
TDM_OUT
TDM_IN
6
7
5
4
(BFXB,CHFD,
CRFD,HPVR,
OLED)
MAIN ASSY
A
MICB ASSY
E
AINB ASSY
C
PNLA ASSY
B
USBA ASSY
D
HPJM ASSY
G
HPJK ASSY
F
DYWXXXX
AK5359ET
AK5358AET
SDRAM(128M)
A3V28S40JTP60
Power suuply control
Voltage monitoring

13
DJM-750MK2
56 7 8
56 7 8
A B C
D
E
F
4.3 POWER BLOCK DIAGRAM
MAIN ASSY
A
OLED ASSY
HMICB ASSY
E
AINB ASSY
C
PNLA ASSY
B
USBA ASSY
D
BFXB ASSY
J
HPVR ASSY
M
CRFD ASSY
CHFD ASSY
I
SW POWER
SUPPLY
N
DDWX4004X4004
DWX39973997
DWX39963996
LIVE
NEUTRAL
DWR14581458
AC
INLET
DKP3988
IC1001
DWX39993999
IC2001
USBB_UCOM
IC1206
High side SW
IC7001
PANEL_UCOM
IC2501
USBA_UCOM
IC3001
DSP
V+1R25D5D
V+1R25D5D
V+3R3D
V+3R3D
V+1R25D5D
V+3R3D
V+5E V+12E
IC1203
V+3R3D
V+12SW
IC1204
V+1R25D V+12SW
IC1202
V+5D V+12SW
IC1207
V+3R3REF
V+5LED
IC1201
V+12SW
IC1205
High side SW
V+5R2D_VBUS
IC1403
V+7R5HP
V- 7R5HP
V+12SW_OPAPA
IC1401
V+12SW_OPA
V+18A
IC1402
V+12SW_OPA
V- 18A
V- 18A_INA_IN
IC1408
V+12A
V+9ADDA
IC1410
V+5A
IC1411
V+3R3A
IC1412
V+5A_REF
IC1405
V- 15A_O
IC1407
V- 15A_IN
IC1409
V+15OLED
IC1404
V+15A_O
IC1406
V+15A_IN
IC1208
V+9LED V+12SW
V+9LED
V+5LED
V+15OLED
V+3R3OLEDED
V+3R3REF
DWX4003X4003
V+3R3A
V+5A
V+15A_IN V- 15A_IN
-
V+5R2D_VBUS
DWX4000X4000
-
V+15A_IN
V- 15A_IN
DWX4010X4010
V+15OLED
V+3R3OLED
V+3R3REF
V+3R3REF
DWX4007X4007
V+3R3REF
DXA2257DXA2257
V+3R3REF
V+3R3OLEDED
V+12E
V+12SW
V+12A
IC7003
V+5E
V+ 5E
V+3R3E
V+3R3E
V+3R3REF
Q1401
IC35093509
V+12SW
V+3R3D_CLKD_CLK
DWX39983998
1
5
V+3R3D_CLKD_CLK
32 2,36,7
13
13
1
3
1
3
1
3
5
1
1
1
3
3
2
2
3
3
7,83
5
4
2
3
2
3
32
51
1
5
1
3
8,12
9
11
5
4
CN1801
CN7004
CN6502
CN5002
CN5001
CN1004
CN5002
CN1005
CN1601
CN2502
CN2
CN1001
CN7001
CN8101
CN7012
CN7601
CN7003
CN7701
CN7602
CN4001
CN1003
CN7006
CN1002
CN7008

14 DJM-750MK2
12 3 4
A
B
C
D
E
F
12 3 4
5. DIAGNOSIS
5.1 STARTUP SEQUENCE
GPIO
SPI HPI
Reset canceled M16_xRST [HIGH]
CPU_MUTE ON [HIGH]
V+12SW_CONT [HIGH]
V+1R25D_CONT [HIGH]
V+3R3D_CONT [HIGH]
V+12A_CONT [HIGH]
V+15D_OLED_CONT [HIGH]
OLED_xRST [HIGH]
Reset canceled SHB_RST [HIGH]
B-PNL_INT [HIGH]
Handshake request
Handshake response & Key notice
DSPPANEL_UCOM USBB_UCOM USBA_UCOM
V+12E ON
V+5E ON
[PANEL_CLK] ON
BOOT
V+3R3EON
[CPU_MUTE] ON
V+3R3D_CONT
[V+3R3D] ON
[V+3R3OLED] ON
[V+5D] ON
[V+3R3REF] ON
[V-15A_IN] ON
V+12SW_CONT
[ V+12SW] ON
[V+12SW_OPA] ON
[V+12A] ON
[V-15A] ON
[V-7R5HP] ON
[V+5A] ON
[V+3R3A] ON
V+1R25D_CONT
[V+1R25D] ON
V+12A_CONT
V+15D_OLED_CONT
[V+15A] ON
[V+15OLED] ON
[V+7R5HP] ON
[USB_CLK] ON
[DSP_CLK] ON
OLED_RST
1stBOOT
VR, KDY Reading
Initialization Start
(Normal mode)
[USB_FA] ON
Continued on next page
Contents of Hardware Contents of Software
Clock GeneratorPOWER SUPPLY

15
DJM-750MK2
56 7 8
56 7 8
A
B
C
D
E
F
GPIO
SPI HPI
Reset canceled A_RST [HIGH]
B-A_INT[HIGH]
Handshake request
Handshake response
Reset canceled MFI_RST [HIGH]
Boot complete notice
Program Load
Load complete
Reset canceled DSP_RST [HIGH]
AUDIO_CLK ON
Handshake request (AAAA)
Handshake response (5555)
AUDIO output
starts at 6 seconds
after reset cancel
Handshake request (BBBB)
Handshake response (7777)
MUTE cancel at
6 seconds after
boot complete
MUTE OFF command
CPU_MUTE OFF [LOW]
1 second after
mute cancel
USB A start command
V5USB_EN[HIGH]
DSPPANEL_UCOM USBB_UCOM USBA_UCOM
Initialization Finish
(Nomal mode)
Starting Normal mode
Starting Normal mode
1stBOOT
MFI_RESET
HSSW ON
[AUDIO_CLK] ON
ADDA Reset canceled
[V+5USB] ON
[CPU_MUTE] OFF
Initialization Start
(Nomal mode)
Initialization Start
(Normal mode)
Initialization Finish
(Normal mode)
From the previous page
Contents of Hardware Contents of Software
Clock GeneratorPOWER SUPPLY

16 DJM-750MK2
12 3 4
A
B
C
D
E
F
12 3 4
5.2 TROUBLESHOOTING
Table of Contents in Troubleshooting
About [Observation Point etc.]
[0] Prior confirmation
[0-1] Confirming inner wire
[0-2] Prior confirmation of power supply
[1] Start troubles
[1-1] Power supply doesn't turn ON. UTILITY
(WAKE UP) is not blinking
[2] Abnormality display
[2-1] MAIN ASSY D2001 is not blinking.
(Lighting state, light-off state)
[2-2] MAIN ASSY D2501 is not blinking.
(Lighting state, light-off state)
[2-3] MAIN ASSY D3001 is not blinking.
(Lighting state, light-off state)
[3] AUDIO INPUT
[3-1] LINE, PHONO cannot be inputted
[3-2] MIC is not inputted
[3-3] RETURN is not inputted
Diagnosis/waveform confirmation-point numbers described
in this section correspond to the numbers on the schematic
diagrams and PCB connection diagrams.
In addition, classify the ASSY in the first alphabet.
[4] AUDIO OUTPUT
[4-1] MASTER1/MASTER2 is not outputted
[4-2] BOOTH is not outputted
[4-3] SEND is not outputted
[4-4] PHONESis not outputted
[5] DVS
[5-1] USB is not recognized
[6] OLED
[6-1] OLED is not lighting
[7] CROSS FADER
[7-1] CROSS FADER operations is abnormal
[7-2] CROSS FADER doesn't operate
[8] USBA
[8-1] Connected devices are not recognized
[8-2] SEND/RETURN is not possible
Output diagnosis = CH1 LINE input
Setting of Switches and Volumes
Troubleshooting
Table
Diagnosis
Point Diagnosis ASSY
[1] [M**]
[P**]
MAIN ASSY
PNLA ASSY
(DWX3997)
(DWX3996)
[2] [M**] MAIN ASSY (DWX3997)
[3]
[M**]
[A**]
[A**]
MAIN ASSY
AINB ASSY
MICB ASSY
(DWX3997)
(DWX3999)
(DWX4000)
[4]
[M**]
[A**]
[A**]
MAIN ASSY
HPJK ASSY
HPJM ASSY
(DWX3997)
(DWX4001)
(DWX4002)
[5] [M**] MAIN ASSY (DWX3997)
[6]
[M**]
[P**]
[M**]
MAIN ASSY
PNLA ASSY
OLED ASSY
(DWX3997)
(DWX3996)
(DWX4010)
[7] [C**]
[C**]
CRFD ASSY
CHFD ASSY
(DWX3258)
(DWX4003)
[8] [M**] MAIN ASSY (DWX3997)
IN/OUT MEASUREMENT
CH INPUT CH INPUT LEVEL
INPUT
FREQUENCY (Hz)
OUTPUT
TERMINATION
REMARKS
IN LINE CH1/2/3/4 0dBV 1k -
IN PHONO CH1/2/3/4 -40dBV 1k -
IN MIC MIC -40dBV 1k -
IN RETURN RETURN 0dBV 1k -
IN USBUSB 1/2/3/4 0dBFS1k -
OUT MASTER 1/2 CH1/LINE 0dBV 1k 10k Ω
OUT BOOTH CH1/LINE 0dBV 1k 10k Ω
OUT SEND CH1/LINE 0dBV 1k 10k Ω
OUT HP/HP mini CH1/LINE 0dBV 1k 32Ω
SWITCH / VOLUME SETTING SWITCH / VOLUME SETTING
TRIM : CENTER CH CUE : OFF
ALL EQ : CENTER MASTER CUE : ON
CH FADER : MAX CROSS FADER ASSIGN : CENTER
MIC LEVEL : CENTER EQ CURVE : EQ
MIC SW : OFF CH FADER CURVE : CENTER
MASTER LEVEL : CENTER CROSS FADER CURVE : CENTER
BOOTH MONITOR : CENTER SEND/RETURN : 1/4" JACK
PHONESVOLUME : CENTER RETURN TYPE : INSERT
HP MONO/STEREO : STEREO SEND/RETURN LEVEL : CENTER
HP MIXING : CENTER
UTILITY SETTING
At the time of diagnosis should
be to the factory reset and factory
default setting.

17
DJM-750MK2
56 7 8
56 7 8
A
B
C
D
E
F
[0] Prior confirmation
[1] Start Trouble
NO. Cause Diagnosis point Confirmation item Treatment Reference
1
Inner wire not inserting,
disconnection,
contact point failure
Related point Confirm that wiring materials are
inserted firmly.
Check the wire for disconnection.
If not inserted, insert firmly.
If disconnected, replace wire.
4.1
OVERALL WIRING
DIAGRAM
[0-1] Confirming inner wire
1
Abnormality of the
power supply of
failure point
Power supply
of the doubted
IC etc.
Check the power supply used for the
points to be diagnosed.
If abnormality is found, locate the power supply
using the power supply map and conduct the repair.
4.3
POWER BLOCK
DIAGRAM
5.3
POWER SUPPLY
DIAGNOSIS
INFORMATION
[0-2] Prior confirmation of power supply
NO. Cause Diagnosis point Confirmation item Treatment Reference
V+12E power supply abnormality or PANEL_UCOM (IC7001) start error may be the cause. In the case of blinking,
refer to "5.3POWER SUPPLY DIAGNOSISINFORMATION."
1
Power supply
abnormal /
Wire abnormal
MAIN ASSY
IC1001 5pin
M1
Check the V+12E power supply. - If V+12E can be checked, go to [2].
- If V+12E cannot be confirmed there is a
possibility of failure of the SW POWER SUPPLY
(DWR1548) or failure of the wires. Replace parts.
4.3
POWER BLOCK
DIAGRAM
2
Power supply
abnormal
MAIN ASSY
IC1001 4pin
M2
Check the V+5E power supply. - If V+5E can be checked, go to [3].
- If V+5E cannot be confirmed there is a possibility of
failure of the IC1001.
Check condition of the solder/replace parts.
4.3
POWER BLOCK
DIAGRAM
3
RESET signal
abnormal
PNLA ASSY
IC70035pin
P18
Check the V+3R3E signal. - If V+3R3E can be checked, go to [4].
- If V+3R3E cannot be confirmed there is a possibility of
failure of the IC7003.
Check condition of the solder/replace parts.
-
4
16MHz CLK
abnormal
PNLA ASSY
X7001 3pin
P1
Check the 16M_CLK signal
(at 1.65 V center, 16 MHz oscillation
waveform).
- If output signal can be checked, go to [5].
- If output signal cannot be confirmed there is a
possibility of failure of the Crystal(X7001) Block.
Check condition of the solder/replace parts.
-
5
PANEL_UCOM reset PNLA ASSY
IC7002 1pin
P19
Confirm that M16_xRST signal
becomes HIGH.
- If the output signal doesn't become HIGH, there is a
possibility of failure of the IC7002.
Check condition of the solder/replace parts.
-
6PANEL_UCOM
failure
PNLA ASSY If it does not improve in the above.
There is a possibility of failure of the PANEL_UCOM
(IC7001).
Check condition of the solder/replace parts.
-
[1-1] Power supply doesn't turn ON. UTILITY (WAKE UP) is not blinking
NO. Cause Diagnosis point Confirmation item Treatment Reference
waveform P1

18 DJM-750MK2
12 3 4
A
B
C
D
E
F
12 3 4
[2] Abnormality display
1
USBA_CLK abnormal MAIN ASSY
IC2501 84pin
M20
Check the USBA_CLK (at 1.65 V center,
13.33 MHz oscillation waveform).
- If output signal can be checked, go to [2].
- If output signal cannot be confirmed there is a
possibility of failure of the Crystal(X2002) Block.
- Check condition of the solder/replace parts.
2
USBB_UCOM to
USBA_UCOM
RESET communication
failure
MAIN ASSY
IC2501 88pin
M19
Confirm that A_RST becomes HIGH. - If A_RST HIGH can be confirmed, go to [3].
- If A_RST HIGH cannot be confirmed,
check the
communication line between
USBB_UCOM and
USBA_UCOM.
-
-
-
3
USBA_UCOM to
FLASH communication
failure
MAIN ASSY - USBA_UCOM(IC2501) to SW IC(IC2004) to
FLASH(IC2003) communication line may have
abnormality.
Check condition of the solder/replace parts.
- Still if symptoms do not improve, replace the PC
board.
[2-2] MAIN ASSY D2501 is not blinking. (Lighting state, light-off state)
1
DSP CLK abnormal MAIN ASSY
IC3002 2pin
M22
Check the DSP_PLL
(at 1.65 V center, 24.576MHz
oscillation waveform).
- If output signal can be checked, go to [2].
- If output signal cannot be confirmed there is a
possibility of failure of the Crystal(X3502) Block .
- Check condition of the solder/replace parts.
2
USBB_UCOM to
DSP RESET
communication failure
MAIN ASSY
IC2001 193pin
M21
Confirm that DSP_RST becomes
HIGH.
- Check the communication line between USBB_
UCOM and USBA_UCOM.
-
-
-
3
USBB_UCOM to
DSP communication
(HPI) failure
MAIN ASSY
M23
- USBB_UCOM(IC2001) to DSP(IC3001) HPI
communication line may have abnormality.
- Check condition of the solder/replace parts.
- Still if symptoms do not improve, replace the PC
board.
[2-3] MAIN ASSY D3001 is not blinking. (Lighting state, light-off state)
As OLED ASSY abnormality display doesn't exist, check the conditions using the three LEDs above the MAIN ASSY.
Each IC may have a communication error.
1
USBB_CLK abnormal MAIN ASSY
IC2001 84pin
M15
Check the USBB_CLK
(at 1.65 V center, 13.33 MHz
oscillation waveform).
- If output signal can be checked, go to [2].
- If output signal cannot be confirmed there is a
possibility of failure of the Crystal(X2002) Block.
- Check condition of the solder/replace parts.
2
PANEL_UCOM to
USBB_UCOM
RESET communication
failure
MAIN ASSY
IC2001 88pin
M14
Confirm that B_RST becomes HIGH. - If B_RST HIGH can be confirmed, go to [3].
- If B_RST HIGH cannot be confirmed, check the
communication line between
PANEL_UCOM and USBB_UCOM.
-
-
-
3
USBB_UCOM to
FLASH communication
failure
MAIN ASSY
M10
M9
M8M7
M10M9
M8M7
- USBB_UCOM(IC2001) to SW IC(IC2004) to
FLASH(IC2003) communication line may have
abnormality.
Check condition of the solder/replace parts.
- Still if symptoms do not improve, replace the PC
board.
[2-1] MAIN ASSY D2001 is not blinking. (Lighting state, light-off state)
NO. Cause Diagnosis point Confirmation item Treatment Reference
NO. Cause
Diagnosis point Confirmation item Treatment Reference
NO. Cause
Diagnosis point Confirmation item Treatment Reference
M20
waveform
M15
waveform
M22
waveform

19
DJM-750MK2
56 7 8
56 7 8
A
B
C
D
E
F
[3] AUDIO INPUT
0
Prior confirmation
PC, LINE, PHONO
changeover switch
Each CH TRIM
CH level meter
Confirm that position is correct.
When you enter the audio, check the
CH level meter is lighting.
- In the case that CH level meter is lighting
=>OUTPUT may be faulty.
Go to [ 4 ] AUDIO OUTPUT
- In the case that CH level meter is not lighting =>go to [1]
Operating
Instructions
1
Parts failure AINB ASSY
CH*_L+/L-,
CH*_R+/R-
[Confirming the input before ADC]
Check the audio signals (sine wave)
via relevant signal route.
[Confirming the input after ADC]
Check the audio signals (other than
sticking to LOW or HIGH) via relevant
signal route.
[Confirming the input after ADC]
Check the audio signals (other than
sticking to LOW or HIGH) via relevant
signal route.
- In the case that audio signal doesn't exist
=>There is a possibility of failure of the analog circuit.
Check condition of the solder/replace parts.
- In the case that audio signal exists =>go to [2]
- In the case that audio signal doesn't exist
=>There is a possibility of failure of the wires.
Replace wires.
- In the case that audio signal exists
=>There is a possibility of failure of the DSP(IC3001).
Replace MAIN ASSY.
- In the case that audio signal doesn't exist
=>There is a possibility of failure of the wires.
Replace wires.
- In the case that audio signal exists
=>There is a possibility of failure of the DSP(IC3001).
Replace MAIN ASSY.
-
-
2
Parts failure AINB ASSY
ADAT_CH*
CN5001(CH1) 38pin
CN5001(CH2) 34pin
CN5001(CH3) 18pin
CN5001(CH4) 14pin
A8
A9
A19
- In the case that signal is sticking
=>There is a possibility of failure of the CH1-4 ADC
and peripheral circuit.
Check condition of the solder of ADC and
peripheral circuit/replace parts.
- In the case that audio signal exists =>go to [3].
[3-1] LINE, PHONO cannot be inputted
0
Prior confirmation
MIC LEVEL TRIM
MASTER level
meter
Confirm that position is correct .
When you enter the audio, check the
MASTER level meter is lighting.
- In the case that MASTER level meter is lighting
=>OUTPUT may be faulty.
Go to [ 4 ] AUDIO OUTPUT
- In the case that MASTER level meter is not lighting
=>go to [1]
Operating
Instructions
1
Parts failure MICB ASSY
beforeTRIM
[Confirming the input]
Check the audio signals (sine wave)
via relevant signal route.
- In the case that audio signal doesn't exist
=>
There is a possibility of failure of previous analog circuit.
Check condition of the solder/replace parts.
- In the case that audio signal exists =>go to [2]
-
A20
2
Parts failure AINB ASSY
after TRIM
IC5904 2pin
[Confirming the input]
Check the audio signals (sine wave)
via relevant signal route.
- In the case that audio signal doesn't exist
=>
There is a possibility of failure of previous analog circuit
or failure of the connector parts between AINB ASSY
and MICB ASSY.
Check condition of the solder/replace parts.
- In the case that audio signal exists =>go to [3]
-
A15
3
Parts failure AINB ASSY
CN5001 40pin
[Confirming the input after ADC]
Check the audio signals (other than
sticking to LOW or HIGH) via relevant
signal route.
- In the case that signal is sticking
=>There is a possibility of failure of the MIC_ADC
(IC5904) and peripheral circuit. Check condition of the
solder of ADC and peripheral circuit/replace parts.
-
A16
[3-2] MIC is not inputted
0
Prior confirmation
•
1/4”JACK
select switch
•
SEND/RETURN_
ON/OFF
switch
•
SEND/RETURN_
LEVEL
- Confirming that switch becomes
[
1/4”JACK ]
- Confirming that SEND/RETURN_
ON/OFF switch becomes ON
- Confirming that SEND/RETURN_
LEVEL is other than MIN
- In the case that CH level meter is lighting
=>OUTPUT may be faulty.
Go to [ 4 ] AUDIO OUTPUT
- In the case that CH level meter is not
lighting =>
go to [1]
Operating
Instructions
1
Parts failure AINB ASSY
RETURN_L/R
[Confirming the input]
Check the audio signals (sine wave)
via relevant signal route.
- In the case that audio signal doesn't exist
=>
There is a possibility of failure of previous analog circuit.
Check condition of the solder/replace parts.
- In the case that audio signal exists =>go to [2]
-
A12
2
Parts failure AINB ASSY
ADAT_RETURN
CN5001 10pin
[Confirming the input after ADC]
Check the audio signals (other than
sticking to LOW or HIGH) via relevant
signal route.
- In the case that audio signal doesn't exist
=>
There is a possibility of failure of the RETURN_ADC
(IC5903) and peripheral circuit.
Check condition of the solder of the ADC and
peripheral circuit/replace parts.
- In the case that audio signal exists =>go to [3]
-
A13
3
Parts failure/
Connection failure
MAIN ASSY
ADAT_RETURN
CN1004 31pin
[Confirming the input after ADC]
Check the audio signals (other than
sticking to LOW or HIGH) via relevant
signal route.
-
M58
[3-3] RETURN is not inputted
NO. Cause Diagnosis point Confirmation item Treatment Reference
NO. Cause
Diagnosis point Confirmation item Treatment Reference
NO. Cause
Diagnosis point Confirmation item Treatment Reference
3
Parts failure/
Connection failure
MAIN ASSY
ADAT_CH*
CN1004(CH1) 3pin
CN1004(CH2) 7pin
CN1004(CH3) 23pin
CN1004(CH4) 27pin
-
M56
waveform A8
waveform A19
waveform A19
[Confirming the input after ADC]
Check the audio signals (other than
sticking to LOW or HIGH) via relevant
signal route.
- In the case that audio signal doesn't exist
=>There is a possibility of failure of the wires.
Replace wires.
- In the case that audio signal exists
=>There is a possibility of failure of the DSP(IC3001).
Replace MAIN ASSY.
4
Parts failure/
Connection failure
MAIN ASSY
ADAT_MIC
CN1004 1pin
-
M57 waveform A16
waveform A12
waveform A13
waveform A13
waveform A16
waveform A15
waveform A20
waveform A9
* Please input RETURN also to Lch even when diagnosing Rch.