Alesis DEQ230 User manual

Confidential Alesis Service Manual 8-31-0103-A
ALESIS
DEQ230 (ME2)
Service Manual
P/N: 8-31-0103-A
The information in this document contains privileged and confidential information. It is
intended only for the use of those authorized by Alesis. If you are not the authorized,
intended recipient, you are hereby notified that any review, dissemination, distribution or
duplication of this document is strictly prohibited. If you are not authorized, please
contact Alesis and destroy all copies of this document. You may contact Alesis at
[email protected].
Copyright ©2002 Alesis Distribution, LLC
ATTENTION!
THIS DOCUMENT CONTAINS SENSITIVE
PROPRIETARY INFORMATION. ALL
RECIPIENTS MUST HAVE A CURRENT NON-
DISCLOSURE AGREEMENT ON FILE WITH
ALESIS DISTRIBUTION, LLC.
DO NOT DISTRIBUTE THIS DOCUMENT IN
ELECTRONIC FORM

Confidential Alesis Service Manual 8-31-0103-A
Preface
This document is intended to assist the service technician in the operation, maintenance
and repair of the Alesis device. Together with the User Reference Manual, this
document provides a complete description of the functionality and serviceability of the
Device. Any comments or suggestions you may have pertaining to the document are
welcome and encouraged.
READ THIS!
In addition to any purchase price that Alesis may charge as consideration for Alesis selling or otherwise
transferring this service manual (“Manual”) to you, if you are not a service and repair facility (“Service
Center”) authorized by Alesis in writing to be an authorized Service Center, Alesis sells or transfers the
Manual to you on the following terms and conditions:
Only Service Centers authorized by Alesis in writing are authorized to perform service and repairs covered
by an Alesis warranty (if any), and transfer of the Manual to you does not authorize you to be an authorized
Service Center. Therefore, if you perform, or if the Manual is used to perform, any service or repairs
on any Alesis product or part thereof, any and all warranties of Alesis as to that product and any
service contract with Alesis for that product shall be voided and shall no longer apply for such
product, even if your services or repairs were done in accordance with the Manual.
All service or repairs done by you or with reference to the Manual shall be solely your responsibility, and
Alesis shall have no liability for any such repairs or service work. All such service or repairs are
performed at the sole risk of the person performing the service or repairs. You agree that all such
work will be performed in a competent, professional and safe manner at all times and to indemnify and
fully hold Alesis and its successors and assigns harmless in the event of any failure to so perform.
Your purchase of the Manual shall be for your own ultimate use and shall not be for purposes of resale or
other transfer.
As the owner of the copyright to the Manual, Alesis does not give you the right to copy the Manual, and
you agree not to copy the Manual without the written authorization of Alesis. Alesis has no obligation to
provide to you any correction of, or supplement to, the Manual, or any new or superseding version thereof.
Alesis shall have the right to refuse to sell or otherwise transfer repair parts or materials to you in its sole
discretion. You shall not use, sell or otherwise transfer spare or replacement parts supplied by Alesis to
you (i) to repair or be used in products manufactured for or by third parties or (ii) to any third parties for
any purpose.
You shall not make any warranties or guarantees with respect to the products of Alesis or the use thereof on
behalf of Alesis or in your own name.
The foregoing describes the entire understanding related to sale or transfer of the Manual to you, and no
other terms shall apply unless in a writing signed by an authorized representative of Alesis.
All Trademarks are property of their respective companies.

Confidential Alesis Service Manual 8-31-0103-A
Warnings
TO REDUCE THE RISK OF ELECTRIC SHOCK OR FIRE, DO NOT EXPOSE
THIS PRODUCT TO WATER OR MOISTURE.
The arrowhead symbol on a lightning flash inside a triangle is intended to
alert the user to the presence of un-insulated "dangerous voltage" within
the enclosed product which may be of sufficient magnitude to constitute a
risk of electric shock to persons.
The exclamation point inside a triangle is intended to alert the user to the
presence of important operating, maintenance and servicing instructions in
the literature which accompanies the product.
REPAIR BY ANY PERSON OR ENTITY OTHER THAN AN AUTHORIZED
ALESIS SERVICE CENTER WILL VOID THE ALESIS WARRANTY.
PROVISION OF THIS MANUAL DOES NOT AUTHORIZE THE RECIPIENT
TO COMPETE WITH ANY ALESIS DISTRIBUTOR OR AUTHORIZED
REPAIR SERVICE CENTER IN THE PROVISION OF REPAIR SERVICES OR
TO BE OR MAKE REPAIRS AS AN AUTHORIZED SERVICE CENTER.
ALL REPAIRS DONE BY ANY ENTITY OTHER THAN AN AUTHORIZED
ALESIS SERVICE CENTER SHALL BE SOLELY THE RESPONSIBILITY OF
THAT ENTITY, AND ALESIS SHALL HAVE NO LIABILITY TO THAT
ENTITY OR TO ANY OTHER PARTY FOR ANY REPAIRS BY THAT ENTITY.

Confidential Alesis Service Manual 8-31-0103-A
Safety Suggestions
Carefully read the applicable items of the operating instructions and these safety
suggestions before using this product. Use extra care to follow the warnings written on
the product itself and in the operating instructions. Keep the operating instructions and
safety suggestions for reference in the future.
1. Power Source. The product should only be connected to a power supply which is described either in
the operating instructions or in markings on the product.
2. Power Cord Protection. AC power supply cords should be placed such that no one is likely to step on
the cords and such that nothing will be placed on or against them.
3. Periods of Non-use. If the product is not used for any significant period of time, the product's AC
power supply cord should be unplugged from the AC outlet.
4. Foreign Objects and Liquids. Take care not to allow liquids to spill or objects to fall into any openings
of the product.
5. Water or Moisture. The product should not be used near any water or in moisture.
6. Heat. Do not place the product near heat sources such as stoves, heat registers, radiators or other heat
producing equipment.
7. Ventilation. When installing the product, make sure that the product has adequate ventilation.
Improperly ventilating the product may cause overheating, which may damage the product.
8. Mounting. The product should only be used with a rack which the manufacturer recommends. The
combination of the product and rack should be moved carefully. Quick movements, excessive force or
uneven surfaces may overturn the combination which may damage the product and rack combination.
9. Cleaning. The product should only be cleaned as the manufacturer recommends.
10. Service. The user should only attempt the limited service or upkeep specifically described in the
operating instructions for the user. For any other service required, the product should be taken to an
authorized service center as described in the operating instructions.
11. Damage to the Product. Qualified service personnel should service the unit in certain situations
including without limitation when:
a. Liquid has spilled or objects have fallen into the product,
b. The product is exposed to water or excessive moisture,
c. The AC power supply plug or cord is damaged,
d. The product shows an inappropriate change in performance or does not operate normally, or
e. The enclosure of the product has been damaged.

Confidential Alesis Service Manual 8-31-0103-A
General Troubleshooting
While this manual assumes that the reader has a fundamental understanding of electronics
and basic troubleshooting techniques, a review of some of techniques may help.
° Visual Inspection -A short visual inspection of the unit under test will often
yield results without the need of complex signal analysis (burnt, or loose
components are a dead giveaway).
° Self Test -Alesis products that utilize microprocessor control contain built in test
software which exercises many of the units' primary circuit functions. Self test
should always be done following any repair to ensure basic functionality.
° Environmental Testing -Applying heat and cold (heat gun/freeze spray) will
often reveal thermally intermittent components (Clock crystals, I.C.s, and
capacitors are particularly prone to this type of failure).
° Burn in Testing -Leaving a unit running overnight often reveals intermittent
failures such as capacitors that begin to leak excess current after a significant
amount of time.
° Cable Checks -Wiggling cables can reveal intermittent failures such as loose
cables or poorly soldered headers. Remember to check power supply cables as
well.
° Flexing the PC Board -Poor solder joints and broken traces can often be found
by pressing the PC Board in various places.
° Tapping Components -Sometimes tapping on a component (particularly
crystals) will cause it to fail.
° Power Down/up -Turning the unit off and back on rapidly several times may
reveal odd reset and/or power supply failures.
° Reset Threshold -A Variac (variable transformer) can be used to check reset
threshold levels. This can be particularly useful in helping customers with low
line problems.
° Compressors -Using a compressor/limiter is often helpful when attempting to
solve low level noise problems, as well as assisting with DAC adjustments.
° Sweep Tests -Sweep generators are very useful in checking the frequency
response envelopes of anti-aliasing filters.
° Piggybacking -Piggybacking I.C.s is particularly useful when troubleshooting
large sections of logic. This is especially true when working with older units.
° Assembly/Disassembly Organization -When removing assemblies, organize
screws and clips with the assemblies that they were removed from. Organizer
trays save a lot of time during re-assembly since similar screws and clips will not
be mixed with each other.

SERVICE MANUAL
6325 31.5 40 50 80080 100 125 160 200 400250 315 500 630 1k 1.25K 2.5k1.6k 2k 5k3.15K 4k 6.3k 8k 16k12.5k10k 20k 31.525 12550 3640 80 100 160 200 315400250 1.6k800500 630 1.25k
1k 2k 2.5k 3.15k 5k 4k 10k6.3k 8k 12.5k 16k 20k
MODEL:DEQ-230
SPECIFICATION
Audio Input
Input Connectors: 2 Impedance-Balanced 1/4”TRS
Jacks
Nominal Input Level: -10dBV (-15dBFS)
Maximum Input Level: +5Dbv (1.78Vrms)
Input Impedance: 10kΩ
Audio Output
Ourput Connectors: 2 Impedance-Balanced 1/4”TRS
Jacks
Nominal Output Level: -10dBV (-15dBFS)
Maximum Output Level: +5Dbv (1.78Vrms)
Output Impedance: 220Ω
Audio Performance
Signal To Noise Ratio: >96 dB A-Weighted, Analog In
toAnalogOut
THD+N: <0.007%,Analog In to Analog
Key features:
• Up/down data buttons that serve dual purpose—to
increment/decrement gain on a selected frequency
band or to select a preset curve from memory
• Two independent channels of 30-bands of 12dB boost
or cut on 1/3-octave center frequencies
• 13-LED resolution of boost or cut per frequency band
• Standard 1-U rack mount chassis
• Analog inputs and outputs with digital internal processing
• 20-20kHz frequency response (+0/-1dB), 0.008% THD,
dynamic range: 103dB (A-weighted)
• Easy-to-use / easy-to-understand user interface
• Individual signal and clip indicator LEDs per channel
• At least 25 user-definable and 25 recallable preset curves
(preset 0 should be “bypass” or “flat” curve)
• Single bypass button affecting both channels
simultaneously
• Channel A-B link button
D:\SERVICE\DEQ-230.DOC
Out
Frequency Response: 22-22kHz±0.50dB, Analog In
ToAnalogOut
Power Consumption: 15 Watts Max (90-230 VAC /
50-60Hz)
Mechanical:
Size: 1.75” Hx 19.0” Wx 5” D
Rack Spaces: 1 Space
Weight: 3.0 1bs. (1.4kg)

DISASSEMBLY PROCEDURES
1. REMOVAL OF TOP COVER / FRONT PAREL (Fig1)
(A) TAKE OUT THE 3PC SCREWS FROM WHICH
THE REAR PAREL.
(B) TAKE OUT THE 3PC SCREWS FROM WHICH
THE TOP PAREL.
(C) TAKE OUT THE 3PC SCREWS FROM WHICH
THEBOTTOMCHASSIS.
Fig.1
2. REMOVAL OF MAIN P.C.B (Fig2)
(A) REMOVE THE 4PC NUT OF 1/4” CONNECTORS.
(B) REMOVE CABLE CONNECTOR
D:\SERVICE\DEQ-230.DOC
Fig.2

DISASSEMBLY PROCEDURES
3.REMOVAL OF FRONT PAREL P.C.B (Fig.3)
(A.) REMOVE THE 3PC OF SUB-PANEL.
Fig.3
D:\SERVICE\DEQ-230.DOC

WIRING DIAGRAM
(US/EU/UK/AUS NZ)
D:\SERVICE\DEQ-230.DOC

Packing Diagram (US/EU/AK/AUS/NZ)

D:\SERVICE\DEQ-230.DOC
Exploded View (US/AU/UK/AUS/NZ)

PARTS LIST
(US/EU/UK/AUS NZ)
NO. PARTS NAME PARTS NO. Q'TY
1 SCREW SC0306AICI 9
2 TOP COVER MT133010101 1
3 CUSHION RUBBER RU1304401 4
4 RACK EAR MT130440201 2
5 FRONT PANEL PT133000101 1
6 LENS NP613ALE01 1
7 BOTTOM CHASSIS MT133030101 1
8 MAIN P.C.B TWPC01C07401 1
9 SUB-PANEL MT1304401 3
10 ASSY FRONT PAREL PCB 9-79-0262 1
11 LED FRAME PT1304301 10
12 RUBBER KEYPAD RU1310601 2
13 CABLE CONNECTOR 4-18-1000 1
14 STICKER BARCODE 7-50-0161 1
15 RUBBER KEYPAD RU131060201 1
16 STICKER WARNING 7-52-0040 1
D:\SERVICE\DEQ-230.DOC

Confidential Alesis Service Manual 8-31-0103-A
Functionality Test
These tests combine checks for EEPROM, LED and Switches.
1) Press the LINK/EXIT and BYPASS buttons on the Known Good ME2 Front
Panel Sub-Assembly and hold these buttons during Step 2. When started in this
manner, the unit will enter Factory Test Mode.
2) Plug the P3 type Alesis Power Supply into a power source and the barrel jack
into the DUT Power In jack.
Verify that the front panel LEDs show normal power up message, “DEQ”
on the left side and “230” on the right side. After this message “TEST”
should display briefly on the left side.
Problems with this inspection indicates that the unit has not entered
Factory Test Mode. Unplug the unit and repeat steps 1 and 2.
3) As soon as the DUT enters Factory Test Mode, the EEPROM is checked.
Verify that the seven segment display DOES NOT read “EE”. The
display should read “00”.
Problems with this inspection indicate that the EEPROM has failed
internal diagnostics.
Failure of this inspection indicate that the DUT cannot continue further
testing.
4) Press Band Button 1. This button is located on the far left hand side of the unit,
underneath the column marked “25”. This button runs the LED COLUMN TEST.
Verify that columns begin to light in order.
Verify that each column lights in order without skipping any columns.
Verify that all the LEDs in a common column light at the same time, and
that two columns are NEVER on at the same time. Verify that when
LEDs in a column are lit, that all the LEDs turn on.
Problems with no response to Band Button 1 indicate Band Button 1 is
faulty and the test has FAILED. Problems with LED inspection indicate
test has FAILED.
Failure of this inspection indicate that the DUT cannot continue further
testing.

Confidential Alesis Service Manual 8-31-0103-A
Front Panel Sub Assembly Test CON’T
5) Press Band Button 2. This button is located on the far left hand side of the unit,
underneath the column marked “31”. This button runs the LED ROW TEST.
Verify that rows begin to light in order.
Verify that each row lights in order without skipping any rows. Verify that
all the LEDs in a common row light at the same time, and that two rows
are NEVER on at the same time. Verify that when LEDs in a row are lit,
that all the LEDs in that row turn on.
Problems with no response to Band Button 2 indicate Band Button 2 is
faulty and the test has FAILED. Problems with LED inspection indicate
test has FAILED.
Failure of this inspection indicate that the DUT cannot continue further
testing.
6) Press Band Button 3. This button is located on the far left hand side of the unit,
underneath the column marked “40”. This button runs the software revision
check.
Verify that the seven-segment display changes.
Verify that the seven-segment display shows the current software revision
number.
Problems with incorrect software revision number indicate that the
incorrect software is being loaded into the DUT, and the test has FAILED.
Problems with no response to Band Button 3 indicate Band Button 3 is
faulty and the test has FAILED.
Failure of this inspection indicate a serious problem with current
firmware for production. The DUT cannot continue further testing, and
the Alesis Engineers listed at the top of this document should be asked for
current software or current version of this document before continuing
production.

Confidential Alesis Service Manual 8-31-0103-A
Front Panel Sub Assembly Test CON’T
7) In order, press Band Button 4 through Band Button 60.
Verify that when the button is held, that the column above the
button lights, that the number corresponding to the button is shown in the
seven-segment display, and that when the button is held, that the LEDs
that are on do not flicker.
Verify that when the seven-segment display shows the button number,
that the display does not flicker, and that all the LEDs for the appropriate
number are lit, and that no extra segments are lit.
Problems with no response or flickering LEDs indicates poor or failed
switch, and the test has FAILED. If there seems to be a problem with the
numbers displayed in the seven-segment display, then the display has also
FAILED.
Failure of this inspection indicate that the DUT cannot continue further
testing.
8) Press the DOWN button.
Verify that the Channel Asignal AND clip LEDs light, and that
when the button is held, that the LEDs that are on do not flicker.
Problems with no response or flickering LEDs indicates poor or failed
switch, OR failed LED. Be sure to verify that BOTH LEDs turn on at the
same time. Either type of problem indicate the test has FAILED.
Failure of this inspection indicate that the DUT cannot continue further
testing.
9) Press the UP button.
Verify that the Channel B signal AND clip LEDs light, and that
when the button is held, that the LEDs that are on do not flicker.
Problems with no response or flickering LEDs indicates poor or failed
switch, OR failed LED. Be sure to verify that BOTH LEDs turn on at the
same time. Either type of problem indicate the test has FAILED.
Failure of this inspection indicate that the DUT cannot continue further
testing.

Confidential Alesis Service Manual 8-31-0103-A
Front Panel Sub Assembly Test CON’T
10) Press the BYPASS button.
Verify that the Bypass LED lights, and that when the button is held, that
the LED does not flicker.
Problems with no response or flickering LEDs indicates poor or failed
switch, OR failed LED. Either type of problem indicate the test has
FAILED.
Failure of this inspection indicate that the DUT cannot continue further
testing.
11) Press the LINK button.
Verify that the Link LED lights, and that when the button is held, that the
LED does not flicker.
Problems with no response or flickering LEDs indicates poor or failed
switch, OR failed LED. Either type of problem indicate the test has
FAILED.
Failure of this inspection indicate that the DUT cannot continue further
testing.

Confidential Alesis Service Manual 8-31-0103-A
Front Panel Sub Assembly Test CON’T
12) Press the STORE button.
Verify that the Channel A signal AND Channel B signal LEDs turn on,
and that when the button is held, that the LEDs that are on do not flicker.
Problems with no response or flickering LEDs indicates poor or failed
switch, OR failed LED. Be sure to verify that BOTH LEDs turn on at the
same time. Either type of problem indicate the test has FAILED.
Failure of this inspection indicate that the DUT cannot continue further
testing.
13) Press the POWER button.
Verify that the unit turns OFF.
Problems with this inspection indicate that the Power button has
FAILED.
Failure of this inspection indicate that the DUT cannot continue further
testing.
14) Press the POWER button.
Verify that the unit turns ON.
Problems with this inspection indicate that the Power button has
FAILED.
Failure of this inspection indicate that the DUT cannot continue further
testing.
15) Unplug the power supply to the DUT. Then unplug all other cabling to the DUT.
This is the end of the Front Panel Sub-Assembly electrical test.

Confidential Alesis Service Manual 8-31-0103-A
Assembly QC
The manufacturer is responsible for QC during the assembly of the unit, including all
procedures to ensure that the final unit is clean and free of marks, scratches, and
smudges.
Before the cover is screwed on
The following suggested check is intended as a rough guide for inspecting the unit before
securing the cover of the unit:
1) Check all components for quality such as scratches, marks, deformities in the
metal work, etc. Check the front lens for scratches, smudges, debris, and other
defects which might cause imperfect viewing of the LEDs behind it.
2) Check all PCB mounting screws. All audio jacks should be secured to the rear
panel with BOTH a washer AND nut.
3) Check all cabling for correct orientation and placement. Make sure the cabling is
secure and will not rattle when the unit is moved or turned upside down
4) Check the fit of all mechanical parts for gaps between pieces that
should fit tightly together.
5) Check sub-panel assembly for proper interaction with the front panel
such as switch mechanical operation and lens fit. Make sure the lens has been
properly glued and does not extend beyond the front panel.
6) Check the silkscreen on the front and rear of the unit for correctness of color and
content against the latest design. Make sure that all artwork is clear and correctly
aligned.
7) Quickly plug the unit into an Alesis P3 type power supply to ensure LEDs light
and proper startup screen appears. While the LEDs are on, check to make sure
that the front lens is clear and working as anticipated.
After the cover has been screwed on
The following suggested check is intended as a rough guide for inspecting the unit after
securing the cover of the unit:
1) Check all components for quality such as scratches, marks, deformities in the
metal work, etc. Check the front lens for scratches, smudges and other defects
which might cause imperfect viewing of the LEDs behind it.
2) Check for all the external screws. Item count to be provided by manufacturer.
3) Check the fit of all mechanical parts for gaps between pieces that
should fit tightly together.
4) Rotate the unit in all directions and listen for any lose parts which may rattle
inside the box. Listen to make sure the cabling has been properly secured.
5) Check to make sure that the proper serial number has been attached to the unit.
6) Clean the unit from all debris and marks caused by handling the unit.

Confidential Alesis Service Manual 8-31-0103-A
Final Assembly QC
Items Required
1 ME2 Assembled Unit (DUT)
1 P3 type Alesis Power Supply
1 CD Player with CD (can be of any music or just test tones)
2 RCA to ¼” PHONE PLUG Cables
2 ¼” PHONE to ¼” PHONE Cables
1 Pair of powered audio monitors such as Alesis M1 Active (8N or 8M)
Assembly
1) Connect CD Player Left Out to DUT Channel A IN using RCA to ¼” PHONE
PLUG Cable.
2) Connect CD Player Right Out to DUT Channel B IN using RCA to ¼”
PHONE PLUG Cable.
3) Connect DUT Channel A OUTto one Alesis M1 Active speaker using ¼”
PHONE to ¼” PHONE Cable.
3) Connect DUT Channel B OUT to one Alesis M1 Active speaker using ¼”
PHONE to ¼” PHONE Cable.
4) Connect IEC power cabling for Alesis M1 Active speakers and turn the
speakers on. Adjust input trim knob to detent (center).
5) DUT is ready for testing. Continue with Power Test.
Power Test
1) Plug the P3 type Alesis Power Supply into a power source and the barrel jack
into the Rear Panel Power In jack.
Verify that the front panel LEDs show normal power up message, “DEQ”
on the left side and “230” on the right side.
Verify that the LEDs do not flicker and are of a consistent brightness.
Problems with this inspection indicates that the front panel sub-assembly
has been incorrectly connected to the rear panel sub-assembly. Open the
unit and inspect the cabling. If the cabling seems faulty or incorrectly
installed, correct the problem and repeat the Power Test. If the cabling
seems okay, then one of the sub-assemblies is damaged and that this
inspection has FAILED.
Failure of this test indicates that this DUT cannot continue testing.
2) Unplug the power supply. Continue with Functionality Test if DUT has not failed.

Confidential Alesis Service Manual 8-31-0103-A
Functionality Test
These tests combine checks for Audio, LED and Switches.
1) Press the LINK/EXIT and BYPASS buttons on the DUT and hold these buttons
during Step 2. When started in this manner, the unit will enter Factory Test Mode.
2) Plug the P3 type Alesis Power Supply into a power source and the barrel jack
into the DUT Power In jack.
Verify that the front panel LEDs show normal power up message, “DEQ”
on the left side and “230” on the right side. After this message “TEST”
should display briefly on the left side.
Problems with this inspection indicates that the unit has not entered
Factory Test Mode. Unplug the unit and repeat steps 1 and 2.
3) When in Factory Test Mode, the unit will bypass audio so that the unit can be
checked for audio integrity. Press Play on the CD player.
Verify that the audio passes through the unit and can be heard on the
Alesis M1 Active speakers.
Problems with this test could be the result of incorrect audio cabling,
speaker setup, or CD Player operation. If these are not the case, then the
unit has FAILED.
Failure of this test indicates that this DUT cannot continue testing.
4) Press Band Button 1. This button is located on the far left hand side of the unit,
underneath the column marked “25”. This button runs the LED COLUMN TEST.
Verify that columns begin to light in order and that the LED pattern is in
working order as in the Front Panel Sub Assembly Test.
Verify that the lens is free of scratches, and that the LEDs have a
consistent and clear appearance.
Problems with no response to Band Button 1 indicate Band Button 1 has
mechanical fit problem and the test has FAILED. Problems with LED
inspection indicate test has FAILED.
Failure of this inspection indicate that the DUT cannot continue further
testing.
5) Press Band Button 2. This button is located on the far left hand side of the unit,
underneath the column marked “31”. This button runs the LED ROW TEST.
Verify that rows begin to light in order and that the LED pattern is in
working order as in the Front Panel Sub Assembly Test.