Alesis D4 User manual

Alesis D4/D5 Drum Modules Service Manual i 02/19/03
ALESIS
D4/DM5 Drum Modules Service Manual
V1.00
10/17/95

Alesis D4/D5 Drum Modules Service Manual ii 02/19/03
PREFACE
This document is intended to assist the service technician in the operation, maintenance and repair of the
D4/DM5 Drum Modules. Together with the D4 and DM5 Reference Manuals, this document provides a
complete description of the functionality and serviceability of the D4 and DM5. Any comments or
suggestions you may have pertaining to the document are welcome and encouraged.
WARNINGS
TO REDUCE THE RISK OF ELECTRIC SHOCK OR FIRE, DO NOT EXPOSE THIS
PRODUCT TO WATER OR MOISTURE.
CAUTION
RISK OF ELECTRIC SHOCK
DO NOT OPEN
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.

Alesis D4/D5 Drum Modules Service Manual iii 02/19/03
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.

Alesis D4/D5 Drum Modules Service Manual iv 02/19/03
Table of Contents
PREFACE ..................................................................................... ii
WARNINGS .................................................................................. ii
SAFETY SUGGESTIONS ............................................................. iii
1.00 General Descriptions............................................................. 1
2.00 Power Supply ........................................................................ 2
2.10 Battery Backup ...............................................................................2
2.20 PUP Circuit .....................................................................................3
3.00 Digital Signal Paths ............................................................... 3
3.10 The 8031 ........................................................................................3
3.11 Reset .................................................................................3
3.12 Memory mapped I/O..........................................................4
3.13 Data Entry Knob And Footswitches ..................................4
3.14 Keypad Decoding ..............................................................4
3.15 MIDI ...................................................................................4
3.20 DM3AG ASIC .................................................................................4
3.21 Address Buss Decoding ....................................................5
3.30 Mask ROMS ...................................................................................6
4.00 Analog Signal Paths .............................................................. 6
4.10 D4 Audio Output.............................................................................6
4.11 D4 Headphone Output ......................................................6
4.20 D5 Audio Output.............................................................................6
4.21 D5 Headphone Output ......................................................7
4.30 Trigger Inputs .................................................................................7
4.30 Analog-Digital Conversion..............................................................7
5.00 Test Procedures.................................................................... 7
5.10 D4 Self Test....................................................................................8
5.20 D5 Self Test....................................................................................8
5.30 Further Testing ...............................................................................9
6.00 Updates and Corrections....................................................... 10
6.10 D4 Updates.....................................................................................10
7.00 Common Solutions ................................................................ 11
8.00 Service Parts Lists ................................................................ 12
8.10 D4 Service Parts List......................................................................12
8.20 D5 Service Parts List......................................................................14
9.00 D4 Software History .............................................................. 16
9.10 Version 1.01 ...................................................................................16
9.20 Version 1.02 ...................................................................................16
9.30 Version 1.03 ...................................................................................17
9.40 Version 1.04 ...................................................................................17
10.00 D5 Software History ............................................................ 18
10.10 Version 1.01 .................................................................................18
11.00 MIDI Implementation ........................................................... 19
12.00 Service Manual History ....................................................... 28
13.00 Schematics.......................................................................... 29
13.10 D4 Schematics .............................................................................29
13.20 D5 Schematics .............................................................................31
13.30 D5 Component I.D........................................................................34
INDEX ........................................................................................... 36

Alesis D4/D5 Drum Modules Service Manual 1 02/19/03
1.00 General Descriptions
The D4 is a rather simple unit to repair, as the component count has been greatly reduced by
the use of the DM3AG ASIC (Application Specific Integrated Circuit). The basic building blocks of the
unit are the 8031 micro controller (which handles all basic unit functions such as triggers , LCD output,
Keypad input, and MIDI I/O), sample generation circuits (ASIC, DAC, Analog switch, and output
filter/buffers), and some miscellaneous support circuits such as system reset, battery backup, etc.
The DM5 (Alesis product code D5) is extremely similar in design, with the one major difference
being the use of better DACs. This has required the addition of on extra IC {D56IFT ASIC} for the
purpose of converting parallel data to a serial format and generating clock signals for use with the new
DACs. In addition this IC consolidates several other functions previously performed by discreet logic
such as memory map decoding and handling the highest order Mask ROM addressing lines. Please
note that there are several main PC Board revisions, and some differences will be noticed from unit to
unit. Reference designators refer to the D4 unless in brackets {D5 reference} or otherwise noted.
Diagram 1

Alesis D4/D5 Drum Modules Service Manual 2 02/19/03
Diagram 2
2.00 Power Supply
The power supply begins with the 9V A.C. 750 mA transformer (Alesis P3 type). After being R.F.
filtered by C26, and passing through the power switch, the A.C. is rectified into -12V, and +12V by D1
{D10}, D2 {D11}, and C2/C3 {C111/C112}, C1 {C108}. Regulators supply the +5V and -5V needed to
run the unit. Note that the +12V raw supply (From D2) {D11} is used by the system reset circuit (see
section 3.11) and battery backup (section 2.10). The D4's +12V and - 12V lines are also used to power
the output op-amps via the PUP Circuit (section 2.20). +5V and -5V lines are used to power the PUP
circuit in the D5.
2.10 Battery Backup
The battery backup circuit is more complex than it first appears, as it requires a good system
reset (see section 3.11) to function properly. The actual backup circuit consists of the 3V battery, a
current testing resistor (R38) {R92}, a steering diode (D6) {D2}, a Diode/Transistor/Resistor
combination (D7, Q3, R24) {D1, Q6, R85} that acts as a steering diode, and filter capacitor C33 {C27}.
The D/T/R combination serves a duel purpose. Besides acting as a steering diode, it also ensures that
the supply voltage level of the SRAM is higher than the level of the data buss. This prevents data
corruption during normal operation.

Alesis D4/D5 Drum Modules Service Manual 3 02/19/03
As mentioned before, the reset circuit is extremely important to battery backup. While covered
more extensively in later sections, it should be noted here that it ties into backup system at the SRAM's
chip enable line (pin 20) via Q4, and ensures that all access to the SRAM is shut off during power up,
and power down. In the case of the D5, reset is tied in through the D56IFT ASIC and Q5.
Any time any part of the backup circuit (including the SRAM) is changed, battery current should
be checked. This is accomplished by measuring the voltage across R38 {R92}. Specification for this is
1mV<VR76<8mV. Most units are in the range of 1mV to 2mV. Values outside of the normal range
usually indicate a problem, and should be troubleshot.
2.20 PUP Circuit
The PUP (quiet Power UP) circuit is designed to prevent the unit from making noise during
power up. The circuit utilizes the RESET line (section 3.11) to control the power supply lines to U42
{U2}, which is the final active stage before the outputs. The circuit essentially consists of a switchable
regulator. Q12 {Q2} and Q14 {Q4} regulate the + and - analog supplies respectively. Q10, Q11, and
Q13 {Q1, Q3} are used to switch the regulating transistors on and off depending on the state of the
RESET line.
3.00 Digital Signal Paths
3.10 The 8031
The 8031 MPU is the heart of the D4/D5's control
section. It handles everything from keypad input and MIDI
I/O, to triggers. Note that the 8031 data buss serves a
dual purpose. This buss multiplexes between low order
addresses (1st 8 bits), and data. Latch U4 {internal to
56IFT ASIC} is used to hold the low order address half,
during 8031 read and write cycles. The (U5) {U15} is
used to hold 8031 program information. The SRAM (U6)
{U16} holds system variables, as well as user parameter
data. Z1 {Z1} provides the 12MHz 8031 clock. MIDI I/O is
handled through the 8031's built in RXD (Read Serial
Data), and TXD (Transmit Serial Data) ports. Piezo input
is handled through the regular 8031 I/O ports. Keypad
decoding, DM3AG ASIC control, and LCD output are
handled through memory mapped I/O (see section 3.12).
3.11 Reset
The reset circuit is perhaps the most singly
important circuit in the D4/D5. Failures in the reset circuit
can cause symptoms ranging from loss of battery backup
to a complete machine lock up. The circuit utilizes the
positive raw supply voltage to determine when the supply
voltage is high enough for the regulators to function
properly. Diagram Error! Bookmark not defined. shows
the sequence of events during power up. When the raw
supply voltage reaches approximately 7.2V, Q1 {Q11}
switches on, pulling the base of Q2 {Q7} low and shutting it off. This allows C32 {C106} to charge via
R23 {R126}. Once C32 {C106} reaches roughly 3V, U7 {U27A} (pins 10 and 11) switches states,
Diagram 3

Alesis D4/D5 Drum Modules Service Manual 4 02/19/03
completing the reset process. The reverse process occurs anytime the raw supply falls below 7.2V.
This ensures that all functions that might cause data corruption are not functioning when the power
supply is unstable.
3.12 Memory mapped I/O
In order to easily control the vast number of hardware functions that the 8031 needs to access, a
system of memory mapped I/O is used. The basic idea is to make hardware functions appear to the
8031 as unused memory locations. That way all that the software has to do is write to a memory
location in order to send that information to a specific device such as the LCD, or ASIC. In the case of
the D5 many of the map decoding functions are incorporated into the D56IFT ASIC, reducing the parts
count relative to the D4.
74HC138 (U12) {D56IFT} performs the majority of the work in this circuit. Two things are
required before U12 becomes active. 1> A15 must be low (i.e. the 8031 is accessing the lower 32K of
address space). 2> The 8031 WRite line must be active (the 8031 is performing a memory write). A15
is used to directly control which function (memory or I/O) is active.
Once U12 is enabled, addresses A12-A14 are decoded by it, and the latch corresponding to the
value of the decoded address is strobed. At this point, data on the 8031 data buss is "written" into the
latch.
3.13 Data Entry Knob And Footswitches
The data entry knob and footswitches are read via the memory mapped latch U11 {U22}. This
allows the 8031 to directly read any changes in the status of these inputs.
3.14 Keypad Decoding
The keypad is handled through a simple polling matrix implemented through the memory
mapped latches U10 and U11 {U20, U22}. Each row is tested by the 8031, one at a time, via U10
{U20}. Any closed switches are read into U11 {U22}, and passed along to the 8031 for interpretation.
3.15 MIDI
The MIDI hardware is a standard implementation. MIDI out/thru begins at the 8031's TXD port
(pin 11) and is buffered with two inverters of U7 {U27}.
MIDI in consists mostly of the opto isolator (U8) {U23}, protection diode D4 {D6}, pullup R18
{R128}, and threshold resistor R19 {R129}.
3.20 DM3AG ASIC
The DM3AG ASIC is a complex LSI device, specifically designed for the purpose of playing
percussion samples. Obviously, the internal workings of such a device are beyond the scope of this
manual, however, a brief description of the important pins follows.

Alesis D4/D5 Drum Modules Service Manual 5 02/19/03
NAME PIN#(s) Function
MD0-MD7 27-34 8031 Data Buss Input.
CLOCK 37 Asic Clock Input (8MHz in SR-16).
DAC0-DAC16 42-51, 53-60 Output to DAC.
A0-A19 3-17, 19-23 Mask Address Buss
D0-D7 61-68 Mask Rom Data Buss
SNH0 39 Output Sample and Hold Control
SNH1 40 " " " " "
SNHIN 41 Output Sample and Hold
Inhibit.
STRES 26 Instruction reset strobe.
STB 25 Instruction latch strobe.
3.21 Address Buss Decoding
Due to the fact that we are pushing the ASIC beyond it's original design, a little extra hardware
was required to accomplish the design goals of the D4. Two limitations needed to overcome. 1> The
address space directly accessible wasn't enough for all of the samples. 2> The ASIC clock speed was
increased from earlier designs to 12MHz, making extra communication from the 8031 more difficult.
This solution to these problems takes the form of an asynchronous decoder. The purpose of the
decoder is to act as an extra set of address lines to ensure that only one Mask ROM is enabled at any
given time.
Diagram 5
Diagram 2

Alesis D4/D5 Drum Modules Service Manual 6 02/19/03
Two bits are required for each sample read (6 Mask ROMs, 0-5). This, plus the fact that there
are sixteen voices available means that 32 bits total are required for each "sample output cycle".
Latches U14-U17 provide the storage area needed to hold all 32 "extra" address bits (which are
provided by the software via memory mapped I/O [see section 3.12]). Binary counters U19-U20 are
used to synchronize the decoding process. U13 is used to decode which latch the current voice's bit
pair will come from, while U18 is used to mask the bit pair itself from the other outputs of the current
latch. U30 does the actual decoding of the bit pair, providing the single Chip Enable needed to access
the desired sample. Note that 1/2 of U43 is used as a one shot multivibrator to extend the time that the
CLear line of the binary counters (U19-U20) is held low slightly longer than SNH0 is low. This is to
ensure that the 8031 has time to communicate necessary parameters to the ASIC before the decoder
starts it's processing.
Since the D5 uses much larger Mask ROMs, this type of decoding scheme is not necessary. The
D56IFT ASIC contains all the extra hardware needed to handle extra address lines not dealt with in the
DM3AG ASIC.
3.30 Mask ROMS
The Mask ROMs contain the all of the sample information. The 18 bit address buss allows for 2
megabytes per Mask ROM. Since Mask ROMs rarely fail, most problems in this area will consist of
opens or shorts along the data and address busses. Mask Roms in the D5 have a 20 bit address buss
(thus only 2 are needed).
4.00 Analog Signal Paths
4.10 D4 Audio Output
Output from the DAC is routed to the four individual output (Main and Aux, Left and Right) by an
analog switch (U39). Output selection is controlled directly by the DM3AG ASIC. Each output section
consists of an output sample capacitor (C96-C99), and a buffer/anti aliasing filter amplifier (U42,
associated resistors and capacitors).
4.11 D4 Headphone Output
The left and right headphone outputs are a sum of the main and aux outputs sent though a pair
of X10 inverting amplifiers. The output impedance is fixed by the sum of the op-amps output
impedance, and R141/R142 in parallel with C34/C35, at roughly 150Ω. This makes the headphone outs
more compatible with 600Ωpro headphones than the 8Ωconsumer variety.
4.20 D5 Audio Output
The outputs of the '4319 DACs are buffered and low pass filtered by U2 (and surrounding
resistors and capacitors) before being routed to the outputs via A.C. coupling capacitors {C11, C3, C35,
C31}. Note that only the main outs run through the volume potentiometer just before being sent to the
outputs. Output impedances are fixed at roughly 300Ω. C1, C2, C29, and C30 provide R.F. filtering at
the outputs.

Alesis D4/D5 Drum Modules Service Manual 7 02/19/03
4.21 D5 Headphone Output
Headphone outputs are taken from the main out lines after the volume potentiometer. These
signal are passed through a gain stage (approximately X10) consisting of U5 and it's associated
circuitry. The signal is R.F. filtered {C42, C43} before passing on to the output jack. Note that supply
lines to U5 are taken from the raw +/-12V. This is to provide the maximum possible amount of
headroom to this output. A lower output impedance than the D4 provides for a little extra current when
using 8Ω"consumer" headphones.
4.30 Trigger Inputs
The trigger input circuitry is much simpler than it might first appear. Note that due to the fact that
the trigger inputs are the same, only "typical" designations appear on the D4 schematic. A chart of
actual part designations appears below the trigger input circuit on the schematic. The input from JT1 is
noise filtered by CT0 and CT1. The two sections of an LM339 act as a differential buffer amplifier,
providing isolation for the input signal. CT2 provides further filtering and smoothing. The signal is then
sent to the analog switches U22 {U11} (trigger ins 1-6) and U23 {U13} (trigger ins 7-12) where it is
multiplexed with the other trigger inputs before analog to digital conversion. Trigger input selection is
handled by the 8031 via memory mapped I/O (see section 3.12) latch U10 {U20} (TRG A0-TRG A4).
The D5s trigger input circuitry is virtually identical to that of the D4. Note that on the D5 schematics all
triggers are shown separately.
4.30 Analog-Digital Conversion
Successive approximation is an empirical approach to the process of analog to digital
conversion. The idea is to divide the process into short, manageable sections. Each significant binary
weight (starting with the Most Significant Bit) is taken in turn, thus requiring only 8 comparisons to
achieve a final value. U2 {U18} is used to buffer the 8031 output ports. These signal are summed
through the binary weighted resistor network consisting of R1-R5 and the resistor SIP R7 {R104-R114,
R137}. This signal is compared to the filtered and shaped trigger input signal. The result of this
comparison is sent back to the 8031. Once the 8031 has obtained a value for all 8 bits, it stores the
final result in memory for further processing, and continues with the next trigger input. Note that when
the 8031 examines the states of the trigger inputs, it doesn't use a specific amplitude to trigger on,
rather it looks for a large change in amplitude over a short period of time. This helps to prevent false
triggering from the other drums in the kit.
5.00 Test Procedures
The D4 contains a number of built in "hidden" routines to assist with troubleshooting and repair
of the D4. These routines include:
$Self Test-Initiates internal diagnostics routines. (Power up while holding the "MIDI" and
"DRUMSET" buttons simultaneously. Use the "MIDI" button to advance to the next test.)
$Reinitialization-Clears memory and resets software parameters to initial values. (Power up
while holding "OUTPUT" and "VOICE" simultaneously.)
$Check Version-Shows current software version. (Select "DRUM SET" Mode. Press
"CURSOR RIGHT" and "CURSOR LEFT" simultaneously.)

Alesis D4/D5 Drum Modules Service Manual 8 02/19/03
5.10 D4 Self Test
The self test consists of several separate routines to check different parts of the D4s circuitry. To
initiate the self test hold "MIDI" and "DRUMSET" while powering up the unit.
The tests include (in order):
√RAM: Tests each location in memory for accuracy. The is not memory destructive.
√ROM: Generates a checksum of all ROM locations and compares it to the correct value stored in
the ROM. The chances of this test failing to identify a true ROM failure are extremely low.
√LEDs: Sequentially lights all LEDs beginning with the upper left corner.
√MIDI: Tests MIDI I/O functions. (A MIDI cable MUST be connected between the D4's MIDI IN and
OUT for the test to operate correctly.)
√Level Check Test: Tests Main and aux output levels.
√Triggers: Test individual triggers (See D5 self test procedures for details)
√Buttons: Tests front panel buttons.
√DAC Adjustment: While listening to the main outs, adjust the DAC trimpot for minimum distortion.
5.20 D5 Self Test
The D5 has two self test modes which allow the running of diagnostic tests on the digital
circuitry. In Individual Test mode, one can select particular tests to run. In All Test mode, the D5 runs all
of the tests in series.
To enter Individual Test mode:
- Power up the unit while holding down the DRUMSET and GROUP buttons. Use the Value Dial to
select which test to run (each test is described below). Press STORE to execute the test. When the test
is complete, you can either select another test to run or exit Individual Test mode by simultaneously
pressing MIX and OUTPUT.
To enter All Test mode:
- Power up the unit while holding down the DRUMSET and MIDI buttons.
Individual Test Descriptions:
1. ROM Test. If the unit passes, the D5 will display "Passed ROM Test" and exit the test automatically.
If the unit fails, the D5 will display "Failed ROM Test!" and won't exit the test. In this case, the user
must press OUTPUT to exit.
2. RAM Test. If the unit passes, the D5 will display "Passed RAM test" and exit the test
automatically. If the unit fails, the D5 will display "Failed RAM test!" and won't exit the test. In this
case, the user must press OUTPUT to exit.
3. LED Test (Individual). Lights up each LED individually. The D5 automatically exits this test after all
LEDs have been lighted.
4. LCD TEST. Lights up all the LCD pixels. Press OUTPUT to exit the test.
5. Switch and Encoder Test. Checks all of the buttons and the rotary encoder. The user must press
every button and rotate the encoder in both directions in order for the test to pass. After pressing all
the buttons, the user should simultaneously press the left and right Cursor buttons. If at this point all
of the buttons have been pressed (i.e., the unit passed), then the D5 will simply exit. If instead not
all of the buttons have been pressed, the D5 will display "Fail Switch Test". The user can either
restart the test (by pressing STORE) or exit the test (by pressing OUTPUT).
6. MIDI In/Out Test. Before running this test the user must connect a MIDI cable from the MIDI Out to
the MIDI In. If the unit passes, the D5 will display "Passed MIDI I/O" and exit the test. If the unit

Alesis D4/D5 Drum Modules Service Manual 9 02/19/03
fails, the D5 will display "Failed MIDI I/O!" and won't exit the test. In this case, the user must press
OUTPUT to exit.
7. Output Test. This tests the four output channels by playing a trio of drum sounds through them.
Pressing the STORE button starts the test. It starts with the Main Left channel. Pressing the
OUTPUT button cycles through the Main and Aux channels, and then exits the test.
8. Trigger Test. This tests the twelve trigger inputs by playing a sound through the MAIN LEFT output,
and triggering a trigger input. A cable must be connected from the MAIN LEFT output to one of the
12 Trigger Inputs, in order from 1 to 12 Pressing the STORE button starts the test. Once the test
has been started, connect a cable from the MAIN LEFT output to the Trigger 1 input ONLY! Do NOT
connect the output to all 12 triggers simultaneously! When the test has started, the LCD will display
the message, "Testing Trig 1". At this point, plug the cable from the MAIN LEFT output into Trigger
Input 1. Soon after, the display should change to "Testing Trig 2". If the display does not change, or
displays the message "Fail Trig 1", then the test has failed for this trigger input. Pressing the
OUTPUT will skip to the next trigger if an error occurs. Once the display shows "Testing Trig 2",
unplug the cable from the Trigger 1 input, and plug it into the Trigger 2 input. The display should
then show "Testing Trig 3". Repeat the process until all 12 triggers have been tested.
5.30 Further Testing
Because of the extensive self test capabilities of the D4/D5 very little extra testing is necessary.
It is always a wise policy to listen to the unit (both through the headphones and via the main and aux
outs) for any signs of distortion. Trigger inputs can be tested using a piezo element (such as the type
commonly used for establishing front panel velocity) wired to a 1/4" jack. MIDI can be further tested
using a sequencer or SYS-EX storage device (SYS-EX is probably more accurate as it allows data
travel to be sent as well as received). As always, it is a good idea to shake the fully reassembled unit to
ensure that no loose components are inside.

Alesis D4/D5 Drum Modules Service Manual 10 02/19/03
6.00 Updates and Corrections
6.10 D4 Updates
Revision C and higher boards require no updates as of this manual release. The remainder of
this section applies to all Revision A and B PCBs unless otherwise noted.
Revision A PCBs will contain many odd jumpers. These were installed at the factory and should
not be of too much concern to the technician.
Revision A & early revision B PCBs have gray ribbon cables between the main and front panel
PCBs. These were found to be unreliable and should be replaced with standard SIL cables
(ALPARTNO 4-19-7511). These same PCBs will also have black headers where the gray cable
attaches. These headers should also be replaced for the same reason.
Add 20pF between left side of D3 and right side of R12. Note that this may already exist on the
bottom of the board. This update filters out audio noise that occurs when the data wheel is in certain
positions.
R153 should be changed from 200k to 100k and the trimpot from 250k to 50k on revision A
PCBs only (later revisions have already incorporated this change). This changes the range of the DAC
adjust circuitry. On some early units the DAC may not be adjusted correctly due to the fact that the
range is not large enough
R9 should be changed to 100Ωfrom 470Ω. This speeds up the response of the output sample
and hold circuitry resulting in a timbrely brighter output.

Alesis D4/D5 Drum Modules Service Manual 11 02/19/03
7.00 Common Solutions
The following table presents solutions to the most common problems that we have seen. Please
be aware that this does mean that every possible scenario is covered here. There is always the
possibility that other "odd" failures may lead to the same symptom. This table should help about 90% of
the time.
NOTE: Due to the fact that the D5 has not been in the field long enough to establish a separate service
history, a separate troubleshooting table will have to wait for future revisions of this manual. While the
following applies specifically to the D4, it is likely that similar symptoms will lead to similar solutions in
the D5.
Described Defect Probable Cause Solution
Unit Dead. Faulty power switch. Replace and retest.
Faulty D1. Replace and retest.
Faulty A.C. Adapter. Replace and retest.
C26 shorted. Replace and retest.
Faulty 7805 regulator. Replace and retest.
Unit locked up. Faulty D1 or D2. Replace and retest.
Faulty 8031. Replace and retest.
Faulty SRAM. Replace and retest.
C32 leaking. (reset cap). Replace and retest.
Only boxes in display. Faulty D1 or D2. Replace and retest.
Faulty LCD. Replace and retest.
Faulty LCD Cable. Replace and retest.
Intermittent reset. Faulty D1.-This can be determined by
checking the voltage at the cathode. If the
peak voltage is less than 9V then the diode
is defective.
Troubleshoot and repair as necessary.
C32 (reset cap). Replace and retest.
No battery backup. Q3 or Q4 shorted. Troubleshoot and repair as necessary.
C33 shorted. Replace and retest.
Faulty SRAM. Replace and retest.
Dead Battery. Troubleshoot and repair as necessary.
Poor solder or missing component on D6. Troubleshoot and repair as necessary.
Trigger failure. Crashed-(check MIDI and external trigger
setups for missing pages).
Troubleshoot and repair as necessary.
Faulty or wrong Q6-9. Troubleshoot and repair as necessary.
Faulty U21. Replace and retest.
Faulty 8031. Replace and retest.
Audio Distortion. Poor connection/bad cable at J5. Troubleshoot and repair as necessary.
Faulty D2. Replace and retest.
Faulty DAC. Replace and retest.
Faulty ASIC. Replace and retest.
Faulty PUP circuit. Troubleshoot and repair as necessary.
No MIDI In. Faulty opto-isolator. Replace and retest.
Faulty 8031. Replace and retest.
No MIDI Out. Faulty U7. Replace and retest.
Faulty 8031. Replace and retest.
Data wheel not working correctly. Faulty shaft encoder. Replace and retest.
Cable at J3 faulty or loose. Troubleshoot and repair as necessary.
No button function/LEDs after repair. J2 or J1 header backwards (up to rev Bs). Key towards front
All trademarks property of their respective companies.

Alesis D4/D5 Drum Modules Service Manual 12 02/19/03
8.00 Service Parts Lists
8.10 D4 Service Parts List
GROUP DESCRIPTION ALPARTNO QTYPER POSITION PCB MANUFACT NOTES
ASS PCB, D4 MAIN ASSY 8-20-0022 1 MAIN BOARD ASSEMBLY
ASS PCB, D4 KEYPAD ASSY 8-20-0023 1 FRONT PANEL (KEYPAD) BOARD ASSEMBLY
CAB 14 PIN DIL 200mm 4-18-0415 1 J4-LCD
CAB 3 PIN SIL 175mm 4-19-0103 1 J6-PHONES PCB
CAB 3 PIN SIL 75mm 4-19-0104 2 J3-ENCODER PCB,J5-VOL PCB
CAB 10 PIN SIL 75mm 4-19-7511 2 J1-KEYPAD PCB,J2-KEYPAD PCB
CAP 0.47 MF ELEC 50V 1-07-1474 12 C4-15 MAIN
CAP 2200 MF ELEC 16V 1-08-2200 3 C1-3 MAIN
CER 1000 PF CERDISC 1-02-0102 1 C31 MAIN
CER 0.01 MF CERDISC 1-02-0103 14 C17,18,44,46,48,50,52,54,59,60,62,63,65,66 MAIN
CER 0.1 MF CERDISC 1-02-0104 39 C16,19,20,23-28,30,30,32-42,55-57,68-76,100,101,102,104,105 MAIN
CER 150 PF CERDISC 1-02-0151 31 C29,43,45,47,49,51,53,58,61,64,67,77,79,80,82,83,85,87,88,90,91,94,95,106-113 MAIN
CER 20 PF CERDISC 1-02-0200 4 C21,22,78, (REV D) C114 MAIN
CER 5000 PF CERDISC 1-02-0502 8 C81,84,86,89,96-99 MAIN
FIL 0.01 MF FILM 1-20-0103 1 C103 MAIN
HDR 03 PIN SIL (SHROUDED) 4-14-0003 6 J3,J5,J6,ENCODER PCB,PHONE PCB,VOL PCB
HDR 10 PIN SIL (SHROUDED) 4-14-0010 4 J1,J2,KEYPAD PCB (2)
HDR 14 PIN DIL 4-14-0014 1
HDW 6-32x1/4 PPB 5-00-0003 2 HEATSINKS MAIN
HDW M3x7mm PHILSLOT 5-00-0020 9 CASE MAIN
HDW 6-32x1/2 STANDOFF 5-02-0003 2 HEATSINKS MAIN
HDW SOLDER LUG 9-03-1036 17 MAIN
HDW RETAINER STRIP 11x200mm 9-13-1019 4 FRONT PANEL
HDW FOAM STRIP 6.5x180mm 9-23-1014 4 FRONT PANEL
HDW FOAM STRIP 6.5x100mm 9-23-1017 4 RACK EAR
IC 7805 +5 V REG TO220 2-11-7805 1 MAIN NAT
IC 7905 -5 V REG TO220 2-11-7905 1 MAIN NAT
IC 74HC138 DEMUX 2-14-0138 3 U12,13,30 MAIN NAT/TI
IC 74HC153 DUAL 4-I/P MUX 2-14-0153 1 U18 MAIN TI
IC 74HC161 BINARY COUNTER 2-14-0161 2 U19,20 MAIN TI
IC 74HC541 OCTAL BUFFER 2-14-0541 2 U2,11 MAIN TI
IC 74HC573 3-STATE LATCH 2-14-0573 1 U4 MAIN TI
IC 74HC574 OCTAL FF 2-14-0574 6 U9,10,14-17 MAIN TI
IC 74HC04 HEX INVERTER 2-14-7404 1 U7 MAIN TI
IC 74HC74 DUAL D FF 2-14-7474 1 U43 MAIN TI
IC 8Kx8 SRAM 58128 2-17-0129 1 U6 MAIN HYUNDAI
IC 27C512 EPROM 2-19-0512 1 U5 MAIN SIG
IC 80C31 MPU 2-20-8031 1 U3 MAIN SIG
IC TLO84 4 OP AMP 2-21-0084 2 U21,42 MAIN TI
IC NE5532N DUAL OP AMP 2-21-5532 1 U41 MAIN SIG
IC LM311 ANALOG COMP 2-22-0311 1 U1 MAIN TI
IC LM339 QUAD COMP 2-22-0339 6 U24-29 MAIN TI
IC 4051 ANALOG SWITCH 2-23-4051 2 U22,23 MAIN ST/HAR/RCA/SIG/PHIL
IC 4052 ANALOG SWITCH 2-23-4052 1 U39 MAIN HAR/PHIL
IC 6N138 OPTO ISO 2-24-0138 1 U8 MAIN TI/SIEMANS
IC PCM54HP 16-BIT DAC 2-25-0054 1 U38 MAIN BURR-BROWN
IC MASK ROM D1 CHIP 1 2-27-0003 1 U36 MAIN TOSH
IC MASK ROM D1 CHIP 2 2-27-0004 1 U35 MAIN TOSH
IC MASK ROM D2 CHIP 1 2-27-0007 1 U34 MAIN TOSH
IC MASK ROM D2 CHIP 2 2-27-0008 1 U33 MAIN TOSH
IC MASK ROM D4-1 2-27-0013 1 U32 MAIN TOSH
IC MASK ROM D4-2 2-27-0014 1 U31 MAIN TOSH
IC DM3ET0 ASIC 2-27-0015 1 U37 MAIN AMI
JAC 5 PIN DIN JACK 4-00-0001 2 MAIN
JAC 1/4 CLIFF (MONO) 4-02-0001 17 MAIN
JAC 1/4 CLIFF (STER) 4-03-0001 1 MAIN
JAC 3.5mm BAR JACK (P3) 4-16-0002 1 J7 MAIN
GROUP DESCRIPTION ALPARTNO QTYPER POSITION PCB MANUFACT NOTES

Alesis D4/D5 Drum Modules Service Manual 13 02/19/03
ME 1N4148 SIGNAL DIODE 2-00-4148 11 D3,4,6-14 MAIN
ME 1N4003 DIODE 2-01-4003 2 D1,2 MAIN
ME 1N5231B ZENER DIODE 2-02-5231 1 D5 MAIN MOT ONLY- NO SUBS
ME 1N5236B ZENER DIODE 2-02-5236 2 D15,16 MAIN MOT ONLY- NO SUBS
ME MPS2369 TRANS 2-03-2369 2 Q4,5 MAIN MOT
ME 2N4401 NPN TRANS 2-03-4401 10 Q1-3,6-12 MAIN NAT
ME 2N4403 PNP TRANS 2-03-4403 3 Q13-15 MAIN NAT
ME LED (RED) SOT-23 3-02-0004 10 KEY
ME DPDT SWITCH (QS) 6-02-0002 1 MAIN
ME PIEZO 7-00-0001 1 KEY
ME 12 MHz CER RES 7-01-0003 1 Z1 MAIN
ME LITH BAT (PANA 3V) 7-05-0003 1 B1 MAIN PANASONIC
ME DATA ENCODER 8-00-1008 1
ME LCD MODULE 9-44-1111 1
MTL RACK EAR 150mm 9-58-1007 2
MTL XTRUDED FRONT PANEL 9-03-1058 1
MTL CASE BOTTOM 150mm 9-03-1059 1
MTL CASE TOP 150mm 9-03-1060 1
PCB PCB, MAIN REV D 9-40-1057 1 (INCLUDES VOL PCB,DATA PCB,HDPH PCB)
PCB PCB, KEY REV B 9-40-1058 1
PLS LCD BEZEL 9-13-1018 1
PLS BUTTON TREE UPPER 9-15-0046 1
PLS LED LENSE 9-15-0047 10
PLS LCD FRAME 9-15-0048 1
PLS VOLUME KNOB 9-15-0049 1
PLS DATA KNOB 9-15-0050 1
PLS SWITCH XTENDER 9-15-0051 1
PLS BUTTON FRAME 9-15-0055 1
PLS BUTTON TREE LOWER 9-15-0063 1
PLS RUBBER KEYPAD 9-23-1025 1
PLS DATA KNOB RUB SLEEVE 9-23-1026 1
POT 50K TRIMPOT 0-08-0502 1 R154 MAIN
POT 5KA SINGLE 0-09-1015 1 R155 MAIN
RES 100 1/8W 5% 0-00-0101 4 R9,141,142,148 MAIN
RES 1K 1/8W 5% 0-00-0102 16 R8,18,21,24-26,38,50,103,111,109,113,114,116,124,145 MAIN
RES 10K 1/8W 5% 0-00-0103 17 R10,19,22,52,53,115,117-120,121-123,125,130,133,140 MAIN
RES 10K 1/8W 5% 0-00-0103 36 R57-59,61-63,65-67,69-71,73-75,77-79,80,81,83,84-86,88,89,91-94,96,97-100,131 MAIN (RT 2-4)
RES 100K 1/8W 5% 0-00-0104 5 R4,46,47,147,153 MAIN
RES 1M 1/8W 5% 0-00-0105 5 R23,110,112,128,129 MAIN
RES 120K 1/8W 5% 0-00-0124 1 R51 MAIN
RES 1.3K 1/8W 5% 0-00-0132 8 R30-37 MAIN
RES 150 1/8W 5% 0-00-0151 4 R39-42 MAIN
RES 2K 1/8W 5% 0-00-0202 2 R20,54 MAIN
RES 20K 1/8W 5% 0-00-0203 12 R56,60,64,68,72,76,82,87,90,95,101,102 MAIN
RES 200K 1/8W 5% 0-00-0204 3 R3,146,152 MAIN
RES 220 1/8W 5% 0-00-0221 9 R14-17,43-45,106,107 MAIN
RES 2.7K 1/8W 5% 0-00-0272 1 R6 MAIN
RES 300K 1/8W 5% 0-00-0304 1 R150 MAIN
RES 390K 1/8W 5% 0-00-0394 1 R2 MAIN
RES 3.9M 1/8W 5% 0-00-0395 1 R151 MAIN
RES 470 1/8W 5% 0-00-0471 5 R11,12,27-29 MAIN
RES 5.1K 1/8W 5% 0-00-0512 8 R13,48,49,55,104,108,132,143 MAIN
RES 51K 1/8W 5% 0-00-0513 3 R5,126,127 MAIN
RES 8.2K 1/8W 5% 0-00-0822 1 R105 MAIN
RES 820K 1/8W 5% 0-00-0824 1 R1 MAIN
RES 910 1/8W 5% 0-00-0911 1 R149 MAIN
RES 22K 9 PIN SIP 0-06-2239 2 R7,139 MAIN
SOC 28 PIN DIP 0.6 4-06-0028 3 U5,6,38 MAIN
SOC 40 PIN DIP 0.6 4-06-0040 1 U3 MAIN
SOC 68 PIN ASIC SOC 4-12-0068 1 U37 MAIN
8.20 D5 Service Parts List
Grp ALPartNo Description Qnt y PCB Ref. Designator Manufact. Comments
ASY 9-79-0157 ASSY PCB MAIN D5 1
ASY 9-79-0158 ASSY PCB FRONT PANEL D5 1

Alesis D4/D5 Drum Modules Service Manual 14 02/19/03
ASY 9-79-0159 ASSY LCD D5 1
CAB 4-18-1627 CABLE DIL 16-PIN 210MM .1 CTR M-F M4 1
CAB 4-18-2020 CABLE 20-PIN DIL 200mm RIBBON 1
CAB 4-19-1331 CABLE SIL 8-PIN 225MM 2MM (REV B) 1
CAP 1-08-0101 CAP 10 uF ELEC 16V 10 C3,4,7,11,24,27,31,35,109,110
CAP 1-08-0105 CAP 1.0 uF ELEC 16V 12 C40,47,48,56,61,62,70,73,80,87,88,95
CAP 1-08-0228 CAP 2200 uF ELEC 16V 3 C108, 111, 112
DIO 2-01-4003 DIODE POWER 1N4003 2 D10, 11
DIO 2-02-5231 DIODE ZENER 1N5231B 1 D12
HDR 4-14-0116 HEADER 16-PIN DIL 0.1 SHROUDED 1 J11
HDR 4-14-1120 HEADER 20-PIN DIL SHROUDED O.1 1 J22
HDR 4-15-1008 HEADER 8-PIN SIL 2MM CTR (SHROUDED) 1
HDR 4-14-0020 HEADER 20-PIN DIL 0.1 XR/CL 1
HDR 4-15-1008 HEADER 8-PIN SIL 2MM CTR (SHROUDED) 1
HDW 5-00-0020 SCREW M-3 x 7mm PHIL SLOT 11
HDW 5-02-0009 HEATSINK M3x20 D4 2 ATTACH TO U28, 29
HDW 5-04-0009 WASHER M3 SPLITLOCK 2
IC 2-24-0138 IC 6N138 OPTO ISO HEWLETT 1 U23
IC 2-27-0039 IC ASIC D56IFT D5/D6 (64PQFPRECT) 1 U12
IC 2-31-0064 IC SOFTWARE EPROM D5 1 MAIN U15 MARSHAL
IC 2-11-7805 REG 7805 +5V TO220 NATIONA 1 U29
IC 2-11-7905 REG 7905 -5V TO220 NATIONA 1 U28
JAC 4-02-0001 JACK 1/4 MONO CLIFF 17 J1-5, 7-10, 12-18, 21
JAC 4-00-0001 JACK 5-PIN DIN (MIDI) 2 J19, 20
JAC 4-16-0002 JACK 3.5MM BARREL (P3) 1 J23
JAC 4-02-0005 JACK CLIFF STEREO (J/SKT S2/BBB BLK PC -A/S 12.5mm) 1
LED 3-02-0012 LED GRN T1 HP HLMP1540 10
LED 3-02-0016 LED BACKLIGHT (GRN) Q2 6
LIT 7-51-1169 CHART SOUND D5 1
LIT 7-51-1170 CHART QUICK SET-UP D5 1
LIT 7-51-1175 MANUAL REFERENCE D5 1
ME 7-05-0003 BATTERY 3V LITHIUM PANASONIC 1 B1
ME 7-01-0009 CRYSTAL 12 MHz 1 Z1
ME 7-00-0001 PIEZO KYOCERA 1
MIS 9-23-1017 STRIP FOAM (SIDE) 7x95mm D4 4
MIS 9-00-1011 ENCODER DATA (ALPS EC11B 15mm w/o SWITCH) 1
MIS 9-23-1014 STRIP FOAM (F/P) 7 x 185mm 4
MTL 9-03-1059 CASE BOTTOM 150MM D4 1
MTL 9-03-1060 CASE TOP 150MM D4 1
MTL 9-58-1007 PANEL SIDE/RACK EAR 150mm 2
MTL 9-03-1036 LUG SOLDER PCB MNT 17
MTL 9-03-0005 EXTRUSION F/P D5 1
MTL 9-03-1165 CLIP STRIP RETAINER 8
PCB 9-40-1174 PCB D5 MAIN 1
PCB 9-40-1215 PCB FRONT PANEL D5 1
PCB 9-40-1219 PCB HEADPHONE D5 1
PLS 9-15-1078 BUTTON POWER Q2/S4/M4 1
PLS 9-15-1117 EXTENDER SWITCH Q2 1
PLS 9-10-0003 BEZEL FRONT PANEL A D5 1
PLS 9-10-0004 BEZEL FRONT PANEL B D5 1
PLS 9-10-0006 BEZEL FRONT LCD D5 1
PLS 9-13-0020 STRIP RETAINER 20mm D5 2
PLS 9-13-0130 STRIP RETAINER 130mm D5 2
PLS 9-15-0087 KNOB DATA M4 1
PLS 9-15-1112 KNOB STANDARD Q2 1
POT 0-09-1022 POT 10KA DUAL CONTROL X2 1
RES 0-05-0020 RES 2 OHM 1/2W 10% 1 R73
RUB 9-23-1061 KEYPAD RUBBER D5 1
Grp ALPartNo Description Qnt y PCB Ref. Designator Manufact. Comments
SMC 1-50-0103 CAP 0.01 uF NPO 1206 12 C41,50,51,58,63,66,71,76,81,89,91,97
SMC 1-50-0104 CAP 0.1 uF NPO 1206 41 C5,6,8,16,17,25,26,28,37,39,42-44,49,52,53,55,57,60,64,67,68,72,75,77,79,84,90,92,93,96,98-107
SMC 1-50-0152 CAP 1500 PF NPO 1206 50V 8 C12, 13, 15, 18, 22, 23, 33, 34
SMC 1-50-0220 CAP 22 PF NPO 1206 2 C82, 83
SMC 1-50-1500 CAP 150 PF NPO 1206 12 C38, 45, 46, 54, 59, 65, 69, 74, 78, 85, 86, 94
SMC 1-51-0015 CAP 0.001uF 1206 2 C29, 30

Alesis D4/D5 Drum Modules Service Manual 15 02/19/03
SMC 1-51-0156 CAP 0.015uF 1206 2 C1, 2
SMI 2-27-0015 ASIC DM3 ETO (SMD) 1 U8
SMI 2-67-5168 IC 8K x 8 SRAM (LH5168N-10L) 1 U16
SMI 2-70-8032 IC 80C31 PQFP SMD 1 U19
SMI 2-71-0084 IC TL084 QUAD OPAMP SMD 2 U2, 25
SMI 2-71-5532 IC NE5532 DUAL OPAMP SMD 1 MAIN U5
SMI 2-76-4319 IC AKM4319 DAC 2 U1, 3
SMI 2-77-0030 IC MASK ROM D5-1 1 U9
SMI 2-77-0043 IC MASK ROM D5-2 1 U7
SMI 2-64-0541 IC 74HC541 OCTAL BUFFER SM 2 U18, 22
SMI 2-64-0574 IC 74HC574 OCTAL D FF SMD 2 U20, 26
SMI 2-64-7414 IC 74HC14 HEX INVERTER 1 U27
SMI 2-72-0311 IC LM311 ANALOG COMP SMD 1 U24
SMI 2-72-0339 IC LM339 ANALOG COMP SMD 6 U4,6,10,14,1721
SMI 2-72-4051 IC CD4051 ANALOG MUX SMD 2 U11, 13
SMM 2-50-4148 DIODE SIGNAL 1N4148 SMD 9 D1-9
SMM 2-51-4401 TRANS 2N4401 NPN SMD 10 Q1, 4-12
SMM 2-51-4403 TRANS 2N4403 PNP SMD 2 Q2, 3
SMR 0-10-0102 RES 1K OHM 1/8W 5% 1206 8 R6, 25-27, 84, 131, 135, 141
SMR 0-10-0103 RES 10K OHM 1/8W 5% 1206 49 R5,19-23,39,40,44-46,52-57,62-64,66-69,71,72,75-77,79,81-83,87-90,92,95-99,101-103,129,133,146
SMR 0-10-0104 RES 100K OHM 1/8W 5% 1206 3 R113, 130, 145
SMR 0-10-0105 RES 1M OHM 1/8W 5% 1206 2 R91, 126
SMR 0-10-0124 RES 120K 1/8W 1206 1 R132
SMR 0-10-0202 RES 2K OHM 1/8W 5% 1206 4 R24, 28-30
SMR 0-10-0203 RES 20K OHM 1/8W 5% 1206 20 R7,12,14,16,17,31,34,38,43,50,51,61,65,70,74,80,86,93,94,100
SMR 0-10-0204 RES 200K OHM 1/8W 5% 1206 1 R112
SMR 0-10-0221 RES 220 OHM 1/8W 5% 1206 14 R3,4,32,33,122-125,127,139,140,143,147,148
SMR 0-10-0222 RES 2.2K OHM 1/8W 5% 1206 2 R138, 142
SMR 0-10-0223 RES 22K OHM 1/8W 5% 1206 14 R104-109, 115-121, 137
SMR 0-10-0272 RES 2.7K OHM 1/8W 5% 1206 1 R134
SMR 0-10-0393 RES 39K OHM 1/8W 5% 1206 8 R8-11, 13, 15, 18, 35
SMR 0-10-0394 RES 390K OHM 1/8W 5% 1206 1 R111
SMR 0-10-0470 RES 47 OHM 1/8W 5% 1206 2 R48, 49
SMR 0-10-0471 RES 470 OHM 1/8W 5% 1206 6 R47, 58-60, 78, 128
SMR 0-10-0472 RES 4.7K OHM 1/8W 5% 1206 6 R1, 2, 36, 42, 85, 144
SMR 0-10-0512 RES 5.1K OHM 1/8W 5% 1206 1 R136
SMR 0-10-0513 RES 51K OHM 1/8W 5% 1206 3 R37, 41, 114
SMR 0-10-0824 RES 820K 1/8W 1206 1 R110
SOC 4-06-0028 SOCKET 28-PIN DIP 0.6 1
SWT 6-02-0002 SWITCH DPDT 1 SW1

Alesis D4/D5 Drum Modules Service Manual 16 02/19/03
9.00 D4 Software History
9.10 Version 1.01
9/15/91
First production release. Changed the offensive drumset names found in version 1.00.
9.20 Version 1.02
12/13/91
1 A triggering bug existed when using two or more drum pads that would cause a pad hit to be
ignored when a neighboring pad had been struck hard immediately before it. This would usually occur on
the second hit of a two pad flam, or on the first hit to a tom pad during a drum-roll on the snare.
2 The trigger TYPE parameter has been replaced with three new parameters. These are the cross-
talk suppression parameter XTALK, the post-trigger decay/recovery time parameter DCAY, and the noise
floor threshold parameter NOISE. To accommodate these new parameters, a new page has been added
under the EXT TRIG functions.
3 The trigger inputs now have an adjustable VCURVE parameter on the first page under EXT TRIG.
(Where TYPE was.) This parameter selects one of seven pad-force to midi velocity response curves to
suit different playing techniques.
4 The diagnostics routine's ram test is now non-destructive.
5 The signal threshold for the diagnostics trigger self-test has been lowered to keep units from
failing unnecessarily in repair.
6 The note number assignment of trigger 9 has been changed on most preset drumsets from 039 D#1
(handclap) to 057 A2 (crash cymbal 2).
7 The dynamic voice allocation scheme has been improved so that voice-stealing is less noticeable.
8 Any system exclusive messages received that included nested midi real-time messages (i.e. timing
clocks, active sensing, start, stop, or continue) would cause the system exclusive data to be ignored and
the SYSEX DATA ERROR message would be displayed. This has been fixed so that any nested real-
time message are ignored, and the sysex data reception continues uninterrupted.
9 A new system exclusive message has been added (opcode 05H) to transmit and receive the new
trigger parameters. The new sysex messages will allow version 1.01 software to upload trigger gains to
version 1.02, but the trigger types will be ignored. Version 1.02 trigger parameters sent to a version 1.01
machine will be ignored completely.
10 The reception of a "System Info Request" system exclusive message (opcode 40H) would result in
the transmission of the complete 25 packet system exclusive dump of the entire D4's memory. This has
been changed so that only the System Info message packet is sent.
11 The system exclusive message that allows an external device to display characters on the LCD
(opcode 04H) had a bug that would cause the SYSEX DATA ERROR message to be displayed instead.
This now works properly.