Akai DPS-24 Service Manual

48V

A / B

LINE
/MIC

TRIM

RECORD
/EDIT
SELECT

ASSIGN

SELECT

INPUT 1

ON OFF

234567891011121

A BA BA BA BA BA BA BA BA BA BA B

123456789101112

0

+60

+600+600+600+600+600+600+600+600+600+600+60

+45

+45

+45

+45

+45

+45

+45

-15

-15

-15

-15

-15

SIGNAL / CLIP

SIGNAL / CLIP SIGNAL / CLIP SIGNAL / CLIP SIGNAL / CLIP SIGNAL / CLIP SIGNAL / CLIP SIGNAL / CLIP SIGNAL / CLIP SIGNAL / CLIP SIGNAL / CLIP SIGNAL / CLIP

23

1

123456789101112

567

13 14 15 16 17 18 19 20 21 22 23 24

-15

4567

8123

L / R 1 / 2 3 / 4 5 / 6 7 / 8

Q-CHANNEL

20Hz

L R

PAN

ON

SOLO SOLO SOLO SOLO SOLO SOLO SOLO SOLO SOLO SOLO SOLO SOLO

TRACK 1 / 13

2 / 14 3 / 15 4 / 16 5 / 17 6 / 18 7 / 19 8 / 20 9 / 21 10 / 22 11 / 23 12 / 24

20Hz

20kHz

20kHz

-

24dB

LOW

-

24dB

+

24dB

+

24dB

Q

SWEEP

23456789101112

GROUP 1 GROUP 2 GROUP 3 GROUP 4 GROUP 5 GROUP 6 GROUP 7 GROUP 8

-15

Q-STRIP
FUNCTION

20Hz

20kHz

-

HIGH

+45

-15

-15

812

456

FX / AUX 1 FX / AUX 2 FX / AUX 3 FX / AUX 4

PAN

PRE PRE PRE PRE EQ ON

FX / AUX 1 FX / AUX 2 FX / AUX 3 FX / AUX 4

24dB

+

24dB

FX RTN 1 FX RTN 2 FX RTN 3 FX RTN 4 L / R

LINE MICLINE MICLINE MICLINE MICLINE MICLINE MICLINE MICLINE MICLINE MICLINE MICLINE MIC

+45

+45

-15

-15

EFFECT / AUX SENDS

A B

LINE MIC

0

+45

+45

-15

34

78

MONITOR
LEVEL

MIN

!!SOLO!!

2-TRACK

MONO

NEAR

STUDIO CR

SELECT

TALK BACK

MASTER

MAX

CLIP

0
2
4
6
8
10
15
20
25
30
35
40
50
60

LR

TB
LEVEL

EXT

MAIN

SYNC

SCREEN

OFFSET

SHIFT

UNDO REDO PRE-ROLL AUTO

FADER BANK

INP

TRACKS

TRACKS

1-12

1-12

13-24

TO FROM IN OUT

OVER

REWIND FAST FORWARD STOP

5

5

F 1 F 2 F 3 F 4 F 5 F 6

HOURS MINS SECS FRAMES

BARS BEATS CLOCKS

SET

GROUP

USER

FX

BANK

AUTO LOCATE

GO TO

LOOP

MEMORY

ABORT

MIX SCENE

DISPLAY
 SELECT

V

.

TRACK CD-RDSP PATCHGRID

RECALLSTORE

ENTERCANCEL

WHEELININP MON

LOCK

RELEASE

CONTRAST

SETUPPROJECTFXAUTOMATEMIXEREDIT

789

456

123

-

JOG  SHUTTLE

Q 1

Q 2

Q 3

Q 4

Q 5

Q 6

CURSOR

ZOOM

+

0

OUT

DIGITAL PERSONAL STUDIO

SERVICE MANUAL

1

##

#

SAFETY INSTRUCTIONS

##

##

# INFORMATIONS

##

1. Parts identified by the } symbol are critical for saf ety.
Replace them only with the parts number specified.

2. In addition to safety, other par ts and assemblies are
specified for conformance with such regulations as those
applying to spurious radiation.
These must also be replaced only with the specified
replacements.
Examples : Noise blocking capacitors, noise blocking filters ,

etc.

3. Use specified internal wiring. Note especially :

1) Wires covered with PVC tubing

2) Double insulated wires

3) High voltage leads

4. Use specified insulating materials for hazardous live parts.
Note especially :

1) Insulation Tape

2) PVC tubing

3) Spacers (insulating barriers)

4) Insulation sheets for transistors

5) Plastic screws for fixing micro switches

5. When replacing AC primary side components (trans­formers, power cords, noise b locking capacitors , etc.), wrap
the ends of the wires securely around the terminals before
soldering.

SYMBOLS FOR PRIMARY DESTINATION

Unit destinations are indicated with letters as shown below.

Symbols Principal Destinations

A U.S.A
B England
E Europe
J Japan

V
X1
X4

MAKE YOUR CONTRIBUTION TO PROTECT THE
ENVIRONMENT

Used batteries with the ISO symbol for recycling as
well as small accumulators (rechargeable batteries),
mini-batteries (cells) and starter batteries should not
be thrown into the garbage can.
Please leave them at an appropriate depot.

PRECAUTIONS FOR LITHIUM BATTERY

The lithium battery may explode when
[OBSERVE THE FOLLOEING WHEN REPLACING]

Germany
Japan
Universal Area

incorrectly replaced.

6. Make sure that wires do not contact heat producing parts
(heat sinks, oxide metal film resistors, fusible resistors,
etc.).

7. Check that replaced wires do not contact sharp edged or
pointed parts.

8. Also check areas surrounding repaired locations.

9. Make sure that foreign objects (screws, solder droplets,
etc.) do not remain inside the set.

SAFETY CHECK AFTER SERVICING

After servicing, make measurements of leakage-current or
resistance in order to determine that exposed parts are
acceptably insulated from the supply circuit. The leakage­current measurement should be done between accessible
metal parts (such as chassis, ground terminal, microphone
jacks, signal input/output connectors, etc.) and the earth ground
through a resistor of 1500 ohms paralleled with a 0.15 µF
capacitor, under the unit’s normal working conditions.
The leakage-current should be less than 0.5 mA rms AC. The
resistance measurement should be done between accessible
exposed metal parts and power cord plug prongs with the
power switch (if included) “ON”. The resistance should be
more than 2.2 M ohms.

• Replace with the same make and type or equivalent recom
mended by manufacturer.

• Place battery in correct polarity.

• Do not short the terminals.

• Do not charge battery.

• Do not dispose of battery in fire.

SERVICE MANUAL

2

I. SPECIFICATIONS

Specifications

Power Supply AC 120V 60Hz (US, Canada), 220-240V 50Hz (Europe) 110W
Operating Temperature 10 - 35° C
Operating Humidity 10% - 60% (without condensation)
Dimensions (mm) 726 (W) x 190 (H) x 579 (D) max. (with LCD tilted down)
Weight 17.8kg (without drive)
Display 320 x 240 dots STN graphic LCD with back light
Sampling Rate 96kHz, 48kHz, 44.1kHz, 32kHz
Quantization Bit 24 bit/16 bit Linear
Recording Media Internal IDE Harddisk
Recording Time With 10Gbyte Harddisk drive (24bit)

FS=96kHz Approx. 9 hrs. 55 min. (12 tracks x 49 min. 45 sec.)
FS=48kHz Approx. 19 hrs. 50 min. (24 tracks x 49 min. 45 sec.)
FS=44.1kHz Approx. 21 hrs. 35 min. (24 tracks x 54 min. 10 sec.)
FS=32kHz Approx. 29 hrs. 50 min. (24 tracks x 1 hour 14 min.)

Frequency Response

FS=96kHz 10Hz - 44kHz +0/-2dB
FS=48kHz 10Hz - 22kHz +0/-2dB
FS=44.1kHz 10Hz - 20kHz +0/-2dB

FS=32kHz 10Hz - 15kHz +0/-2dB
ADC 24bit 128-times oversampling, enhanced dual bit delta/sigma modulation
DAC 24bit 8-times oversampling, advanced segment delta/sigma modulation
Dynamic Range 104dB or more (30kHz LPF, FS=44.1kHz)
Distortion Ratio 0.003% or less (1kHz, 44.1kHz)
Channel Crosstalk 80dB or less (10kHz referenced, 100 ohms terminated)
Wow & Flutter Below measurable level
Analog Audio Input Inputs A

1 - 4ch 6.3mm Stereo Phone/XLR Combo Jack - balanced

Phantom Power provided (switchable) for XLR connection

5 - 12ch 6.3mm Stereo Phone/XLR Combo Jack - balanced

Inputs B

1 - 12ch 6.3mm Stereo Phone Jack - balanced

Hi-Z 12ch 6.3mm Phone Jack - unbalanced

ADC In 6.3mm Stereo Phone Jack - balanced

AUX In 6.3mm Stereo Phone Jack - balanced

2-Track RCA - unbalanced
Input Level Mic mode -62 - -2dBu (+16dBu max. balanced, 1kHz)

Line mode -47 - +13dBu (+31dBu max. balanced, 1kHz)
Hi-Z -68 - -8dBu (+10dBu max. unbalanced, 1kHz)
ADC In +4dBu (+22dBu max. balanced, 1kHz)
AUX In +4dBu (+22dBu max. balanced, 1kHz)
2-Track -14dBu (+4dBu max. unbalanced, 1kHz)

Impedance Mic mode 3k ohms (1 - 12ch)

Line mode 12k ohms (1 - 12ch)
Hi-Z 1M ohms
ADC In 10k ohms
AUX In 10k ohms
2-Track 15k ohms

Analog Audio Output Stereo Out 6.3mm Stereo Phone - balanced

Main (monitor) 6.3mm Stereo Phone - balanced
Nearfield (monitor) 6.3mm Stereo Phone - balanced
Studio Out 6.3mm Stereo Phone - balanced
Direct Out 6.3mm Stereo Phone - balanced
AUX Sends 1 - 4 6.3mm Stereo Phone - balanced

SERVICE MANUAL

3

Output Level Stereo Out +4dBu (+22dBu balanced max., 20k ohms load)

Main (monitor) +4dBu (+22dBu balanced max., 20k ohms load)
Nearfield (monitor) +4dBu (+22dBu balanced max., 20k ohms load)
Studio Out +4dBu (+22dBu balanced max., 20k ohms load)
Direct Out +4dBu (+22dBu balanced max., 20k ohms load)
AUX Sends 1 - 4 +4dBu (+22dBu balanced max., 20k ohms load)

Impedance Stereo Out 1k ohms - balanced

Main (monitor) 1k ohms - balanced
Nearfield (monitor) 1k ohms - balanced
Studio Out 1k ohms - balanced
Direct Out 1k ohms - balanced
AUX Sends 1 - 4 1k ohms - balanced

Stereo Phones Output x 2, 6.3mm Stereo Phone Jack - adjustable

Max. Output 155mW/32 ohms
Digital Audio Input x 1, RCA (SPDIF) 2-channels assignable
x 1, MP Light Pipe (adat/SPDIF) 8-channels/2-channel assignable

Digital Audio Output x 1, RCA (SPDIF) Master Output

x 1, MP Light Pipe (adat/SPDIF) 8-channels assignable/Master Output
Wordclock x 1, BNC - In/Out
Foot switch x 1, 6.3mm Phone Jack
MIDI x 3, 5 pin DIN - IN, OUT, THRU
ASCII Keyboard x 1, 6 pin Mini-DIN
Accessories 3-prong Power Cable

Internal Disk Mounting Kit

Operator’s Manual
Options IB-24LTC - SMPTE/EBU LTC Interface Board

IB-24ADT - 16-channel adat Interface Board w/adat Sync

IB-24SCSI - SCSI Interface Board

*0dBu = 0.775Vrms

The specifications are subject to change without prior notice.

SERVICE MANUAL

4

II. DISASSEMBLY

In case of trouble, etc., necessitating dismantling, please dismantle in the order shown in the illustrations . Reassemb le in the
reverse order.

1. Removal of the FRONT PANEL BLOCK

ZS-378447
ST BID40X10STL BNI

ZS-378447
ST BID40X10STL BNI

ZS-331182
BT BID30X08STL BNI

ZS-331182
BT BID30X08STL BNI

ZS-331182
BT BID30X08STL BNI

SERVICE MANUAL

5

ZS-331182
BT BID30X08STL BNI

ZS-331182
BT BID30X08STL BNI

2. Removal of the BOTTOM COVER

ZS-331182
BT BID30X08STL BNI

ZS-331182
BT BID30X08STL BNI

SERVICE MANUAL

6

III. PRINCIPAL PARTS LOCATION

PC CONTROL BLK

PC OPERATION R BLKPC FADER BLK

PC OPE-DIST BLK

PC JOG BLK

PC OPERATION L BLK

PC PRE-AMP BLK PC INPUT B BLK

PC CPU BLK

PC AUX IN

PC INPUT A BLK

PC MOTHER BLK

PC LED PAN BLK

PC POWER BLK

PC FILTER BLK

PC PAN ENC BLK

POWER SW BLK

PC HP-HIZ BLK

PC ADDA BLK

SERVICE MANUAL

SW POWER BLK

7

IV. SUPPLEMENTARY INFORMATION

1. Test Mode

While pressing the SHIFT button, press the CANCEL button to enter the DEBUG PAGE. To leave the DEBUG
page, press the MAIN SCREEN button. Return to the DEBUG PAGE from any TEST MODE by pressing the
CANCEL button while the SHIFT button is being pressed.

1-1. F1 (BUFFERS)

For confirmation of DISK BUFFERS LEVEL.

1-2. F3 (PANEL)

For confirmation of FADER TOUCH SENSE operation.

F1/F2 (RED TRACK LEDS)
To check whether red LED operation is correct or not.
The RECORD/EDIT SELECT LED, SIGNAL CLIP LED will light up in red.
All other LEDs will light.

F3/F4 (GREEN TRACK LEDS)
To check whether green LED operation is correct or not.
The RECORD/EDIT SELECT LED, SIGNAL CLIP LED will light up in green.
NOTE: After LED CHECK, even when the DEBUG mode has been escaped from, all LED indicators will go
out and only renewed modes will light up in order.

1-3. F4 (AUDIO)

The input AUDIO signal will be output to dircet according to display indicator specification. The main

purpose of this function is for factory testing.

1-4. F2 (MIX DSP) F6 (PATCH)

Not operational at V1.0.

2. PANEL OPERATION TEST MODE

This mode is operated by the OPERATION CPU and is not affected by the CPU circuit of the CPU PCB. This test
mode will operate even if the CPU PCB is not operating properly. Turn the power on while pressing down the
REWIND, FAST FORWARD, STOP and PLAY buttons.
This mode can be used to confirm correct operation of the SWITCH, FADER VR, MONITOR VR, JOG, SHUTTLE
and ENCODER. However, A/B SW, LINE/MIC SW, TRIM, TB LEVEL, PHONE LEVEL are omitted.

NOTE: FADER operation directly after power has been input cannot be tested.

3. OTHER HIDDEN MODES

3-1 With the SHUTTLE knob turned fully to the right, turning the power on will immediately access the VERSION

UP mode via the USB.

3-2 With the SHUTTLE knob turned fully to the left, turning the power on will boot up the system without

running a hard disc check.
This mode is convenient when the system will not startup because of hard disc data.

3-3 With the SHUTTLE knob turned 1/4 to the left, turning the power on will check hard disc content and start up

the system in PROJECT initial settings. Normally the DPS24 starts up in the last PROJECT created. This
mode is convenient when there is a problem with the last PROJECT data and the system won't start up.

SERVICE MANUAL

8

4. JIG PC BOOT DPS24 (PART No. BA-771030J)
JIG PC BOOT is used for BOOT BLOCK recovery and for CPU circuit testing etc.
Insert in SLOT 1 on the OPTION BOARD. Make sure the power is off before inserting. The JIG PC BOOT will not
work in any other slot besides SLOT 1.
When the DPS24 power is turned on, the SELF CHECK function will operate to check each CHIP. If a fault is found
somewhere, FAILED will appear and operation will stop.
FAILED will appear when nothing after MIDI SPDIF, WCLK, ASCII are connected, but this is not an indication of
faulty operation.

5. OS BOOT BLOCK RECOVERY PROCEDURE

Insert the PC JIG BOOT into SLOT 1. Make sure the power is off before inserting. The JIG PC BOOT will not w ork
in any other slot besides SLOT 1.

1. When the DPS24 power is turned on, the SELF CHECK function will operate to check each CHIP. After confir-

mation, the screen will normally be returned to.

2. Press the SETUP button, then the F6(OS) button.

3. Press the F2/F3/F4 (upgrade from EPROM) button.

4. Press the F6(YES) button.

5. Press the F6(OK) button.

6. OS UPDATE PROCEDURE

• OS UPDATE FROM CD-ROM

You can update the OS from the built-in CD-ROM drive. Please use a CD-ROM that contains the OS for the
DPS24.
You can create the OS disc by using your PC's CD-R/W function to write the “DPS24.bin file” onto an ISO 9660
CD-ROM disc.

1. Turn the DPS24 on and insert the OS disc

2. Press the SETUP button, then the F6(OS) button.

3. Set “Update from” to “CD” with Q1 knob.

4. Press the F5/F6 (UPGRADE) button.

5. Confirm the displayed OS version. If not displayed, repeat the procedure.

6. If the correct version is displayed, press the F6(YES) button.

7. Press the F6 (OK) button.

8. Reboot the DPS24.

• OS UPDATE FROM USB

The OS update can be made from the PC via the USB port.
You must have the "OS Loader software for DPS24".
The following files are required for the update:
dps24usb.sys (USB set up file)
dps24usb.inf (USB set up file)
usbrom.exe (USB transmission software)
dps24.bin (OS file for DPS24)
These files must be placed in the same folder. (eg. c:\DPS24)

Installing the USB drivers:

1. Connect USB cable between DPS24 and PC.

2. Power up the PC and let it complete the boot up process.

3. Power up the DPS24.

SERVICE MANUAL

9