Alesis 3630 User manual

3630 Compressor/Limiter
And
NanoCompressor
Service Manual V 1.00e
5/1/97
T.J. Goodwin
Editor
WWW.ALESIS.COM
Alesis 3630Compressor Service Manual 1.00 i 12/11/02

PREFACE
This document is intended to assist the service technician in the operation, maintenance and repair of
the 3630 Compressor/Limiter and the NanoCompressor. Together with the 3630 and NanoCompressor
Reference Manuals, this document provides a complete description of the functionality and
serviceability of these units. 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 3630Compressor Service Manual 1.00 ii 12/11/02

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 3630Compressor Service Manual 1.00 iii 12/11/02

Acknowledgments
As editor of this book I receive a great deal of credit for it’s existence. But without the
help of the Alesis service team, this book could not reach the standards we have set for it. In
particular I would like to thank Robert Morin, John Sarappo, and Gary Stafford for their extra
effort in proofreading this material to ensure that it does live up to our standards. In addition I
would like to thank Don Wichman for the QC Test Procedures included here.
T.J.Goodwin
Technical Services Coordinator.
Alesis 3630Compressor Service Manual 1.00 iv 12/11/02

Table Of Contents
PREFACE..........................................................................................................ii
WARNINGS.......................................................................................................ii
SAFETY SUGGESTIONS .................................................................................iii
Acknowledgments .............................................................................................iv
1.00 General Descriptions .................................................................................1
1.10 3630 Compressor/Limiter....................................................................1
1.20 NanoCompressor................................................................................1
2.00 Power Supplies..........................................................................................1
3.00 Signal Paths ..............................................................................................2
3.10 Audio Signal Paths..............................................................................2
3.20 Control Signal Paths ...........................................................................2
3.21 Compression Detector 2
3.22 3630 Gate Detector 3
3.30 LED Displays ......................................................................................3
3.40 3630 Schematic Cross Connections ...................................................3
4.00 Test Procedures ........................................................................................5
4.10 Distortion Adjustments ........................................................................5
4.20 Input/Output Level Test.......................................................................6
4.30 Function Test ......................................................................................7
4.40 Stereo Mode Test ...............................................................................7
4.50 Final Test ............................................................................................8
5.00 Troubleshooting.........................................................................................9
6.00 Updates And Corrections...........................................................................9
6.10 3630 Changes.....................................................................................9
6.11 Revision B Main PCB Distortion Reduction. 9
6.12 Power Up Oscillation 10
6.13 Revision C Main PCB Dual/Stereo Switch Noise 10
6.20 NanoCompressor Changes.................................................................10
6.21 Revision B Main PCB Right Channel Sensing Resistor 10
6.22 Revision C Right Channel Normalization 11
6.23 Improvement of High Frequency Phase Response 11
6.24 Improvement of Power Supply Stability Under High Output Loading....11
7.00 Service Parts List.......................................................................................12
7.10 3630 Service Parts List .......................................................................12
7.20 NanoCompressor Service Parts List ...................................................14
8.00 Service Manual History..............................................................................16
9.00 Dictionary of selected terms ......................................................................16
INDEX................................................................................................................17
10.00 Schematics ..............................................................................................20
Alesis 3630Compressor Service Manual 1.00 v 12/11/02

1.00 General Descriptions
This manual includes two Alesis products. The Alesis 3630 Compressor/Limiter (CL) and
the NanoCompressor (NC). Note that 3630 reference designators are in plain text while
NanoCompressor designators are in bold and placed in [brackets] in order to distinguish them
from each other.
1.10 3630 Compressor/Limiter
The 3630 Compressor is a general purpose dual/stereo compressor/limiter and noise
gate in a single rack space. It has the ability to utilize both hard knee (fixed ratio) and soft knee
(ratio dependent on
incoming signal levels)
compression techniques
allowing for a greater
range of applications. It
also incorporates a
noise gate similar to the
Alesis MicroGate. The
unit is divided internally
into two sections
(master and slave). The
schematics for these
two sections are virtually
identical, except for
minor differences in the
way that functions are
switched on and off. The
simplified block diagram
(Figure 1) shows the
generic signal paths for
one channel of the unit.
Figure1-3630 Simplified Block Diagram
1.20 NanoCompressor
Introduced in late 1996, the NanoCompressor consists mainly of the compressor section
from the 3630, in a small 1/3 rack space case. This product includes the same hard knee/soft
knee compression available in the 3630. Note, however the NanoCompressor is permanently
wired for stereo operation (no dual mode).
2.00 Power Supplies
The power supply begins with the 9 volt A.C. adapter (Alesis P3 type). C1 acts as an RF
filter capacitor before on/off switch S1. In the NanoCompressor there is no switch, so the
adapter connects directly to the doubler/regulator section via the P.S. input jack [J1]. The +15V
rail is derived from the 9V A.C. via a voltage doubler (C3, C4 and D3, D4) [C2, C34 and D1, D3],
a +15V regulator (VR1) [U8], filter capacitor C6 [C12], as well as a multitude of bypass
capacitors spread thoughout the PC Board. The -15V supply is a mirror of the positive supply,
consisting of a doubler (C2, C5 and D1, D2) [C1, C25 and D4 D2], regulator (VR2) [U1] and filter
capacitor (C7) [C9], as well as the usual bypass capacitors.
Alesis 3630 Compressor Service Manual 1.00 1 12/11/02

3.00 Signal Paths
In the discussion of signal paths, concentration will be centered on the 3630 master
schematic. The slave functions are virtually identical to the master, the only difference being in
the way that the front panel switches control various functions. Individual switch connections are
discussed in section 3.40. Similarly, since the NanoCompressor utilizes the same basic circuitry
as the 3630, and both left and right channels function identically, only the left channel is
discussed here.
3.10 Audio Signal Paths
The input from J2 [J3] is R.F. filtered by C12 [C3] and has it's impedance set at 100K
[1M] by R12 [R1]. One section of U2 [U2] acts as a buffer/gain stage. Note that the -10/+4 switch
S2 works by adding a voltage divider element (R13) to the negative feedback path of the op-
amp (reducing negative feedback, thus increasing gain) when the switch is in the -10 position.
Also note that the NanoCompressor is permanently wired for -10 systems. The output of this op-
amp is sent to both the side chain jack J3 [J2] (and consequently on to the detectors) and to the
Voltage Controlled Amplifier (U3) [U4] via an A.C. coupling capacitor (C16) [C7] and current
limiting resistor R23 [R36]. Please note here that the VCA is a current amplifier and as a
consequence, signals present at the VCA will not be visible on an oscilloscope. The output of
the VCA is converted back into voltage mode by U2 pins12,13, and 14 [U2 pins 12, 13, and 14]
before being sent to the output via the -10/+4 switch. S2 which reduces output gain by adding
an extra voltage divider (R41, R42) when in the -10 position. Again note that the
NanoCompressor has no equivalent switch. Finally, the output is current limited to 470Ωby R26
[R5] before output jack J4 [J5].
3.20 Control Signal Paths
3.21 Compression Detector
The purpose of the compression detector is to vary the audio VCA control signals
according to the front panel settings of the compressor section. In the 3630, this hardware must
work in conjunction with the gate detector to produce the necessary control signal for the audio
VCAs.
The compression detector is based on the use of the 2252 RMS level detector IC U1.
[U3] The output of the detector rises roughly 6mV for every dB of input level. R7 Is used as a
symmetry adjust and should be set for minimum distortion (see section 4.10 for details). The
output of the 2252 is then sent to an active rectifier (U2 pins 5,6 and 7) [U3 pins 5,6 and 7]. The
threshold control works by biasing the input to the rectifier with a D.C. offset. The output of the
rectifier will not change until the output of the 2252 exceeds the threshold voltage set by R119
[R88]. The HARD KNEE/SOFT KNEE switch in the SOFT position incorporates R83 [R64] which
allows program material to have a greater effect on the final control voltage as well as affecting
the ratio setting.
At this point, U2 pins 1, 2, and 3 [U7B pins 5 6, and 7] provide a small amount of gain
prior to entering the envelope shaping circuitry. RC networks consisting of R121, C29, C39
[R83, C36 and C40] and R78, R122, C40 [R82, R52, C26] work in conjunction with U8 pins 1, 6,
and 7 [U6A pins 2, 4, and 5] to provide the attack/release shaping for the control signal. The
rest of the compression circuitry consists of some filtering, with R123 [R79] providing for output
gain level by adding a DC offset to the final control voltage. It is worth noting again here that the
VCA functions in current mode causing the “Control Voltage” to be unviewable using an
oscilloscope.
Alesis 3630 Compressor Service Manual 1.00 2 12/11/02

3.22 3630 Gate Detector
The purpose of the gate detector is to vary the audio VCA control signals according to the
front panel settings for the noise gate. In accomplishing this, it must override the compressor
detector when the gate itself is in the closed position, yet still allow the compressor detector to
function during the release portion of the noise gates normal cycle. It’s also worth noting here
the economy of parts used by the Alesis Engineers. Instead of leaving some sections of a quad
comparator unused, and needing to add at least a dual op amp to each channel, they instead
opted to use the comparators in a linear mode. Since we are only using the audio signal for
amplitude detection purposes at this point, the degradation of the audio signal caused by using
these parts is not an issue.
The circuit begins with audio signal input via the side chain jack J3. This signal is A.C.
coupled via C24, and provided with some gain by U4 pins 8, 9, and 10. The signal is then
buffered (U9 pins 10, 11, 13, 8, 9, and 14) and filtered (C44) prior to entering the threshold
detector.
The threshold detector consists of a simple level detector with hysteresis (U9 pins 6, 7,
and 1). It’s threshold level is set by R124. This signal is then rectified (D9, D10) and filtered
(R89, C45) to further shape the control signal as well as prevent the system from reacting too
quickly (i.e. causing the gate to “chatter” when the audio level and threshold level are roughly
equivalent).
Immediately following the threshold detector is the rate circuit, whose main components
consist of U9 pins 5, 6, and 7, Q1, C20, and R125. While the gate is in the open position, the
base of Q1 is held at -15V (turning it on) forcing the voltage across C20 to stay low (about 0.7V).
As soon as the threshold is exceeded and the gate is closed, the base of Q1 jumps to +10V
(turning it off) and allowing C20 to charge at a rate determined by the rate potentiometer (R125).
The signal is finally buffered and mixed with the output of the compression detector via
D5, R32, R30 and C19. Note that D5 helps prevent component damage under conditions when
the compression detector signal and gate detector signal combined might cause excessive
reverse currents.
3.30 LED Displays
While there is an obvious difference between the sensitivities of the LED bar graph
displays of the 3630 and the NanoCompressor, they both use the same basic circuit to generate
it. Here we will use the 3630 master input output LED bar graph as an example.
U18 buffers the incoming signal and C66 acts to low pass filter the signal (without this the
LEDs might only light briefly making it look dim). Q5 and Q6 provide a constant current so that
the LEDs maintain a constant brightness no matter how many are on. U15-U19 compare the
incoming signal to a series of set threshold values (set by R151-R162).
In the 3630 the gain reduction LEDs lack the input signal buffer and low pass filtering as it
is already slow enough to hold the LEDs on long enough to stay visible.
3.40 3630 Schematic Cross Connections
Due to the relative complexity of the various connections between master and slave, it
can be difficult to follow the various connections throughout the schematics. The following table
is presented to help simplify troubleshooting.
Connection Designation Function
T1 Sets correct path for the cap input of slave 2252 (U5), according to the state of the
stereo/dual switch.
Alesis 3630 Compressor Service Manual 1.00 3 12/11/02

T2 Connects master rectifier control signal U9 pins 13 and 14 to stereo dual switch S6
(Slave section).
T3 Connects output of master noise gate detector to slave gate LEDs, depending on
the state of the stereo/dual switch.
T4 Connects master bypass switch S10 to slave stereo dual switch S6. Used to
determine the correct source of input to the gain reduction LEDs, depending on the
state of the stereo/dual switch.
T5 Connects master bypass switch to stereo/dual switch to provide the correct path for
the VCA control voltage signal, depending on the state of the stereo/dual switch.
T6 Connects the master gain reduction LEDs to the stereo/dual switch.
T7 Connects channel A input (U2 pin 8) to input side of monitor switch 9.
T8 Connects channel A final output (Just prior to -10/+4 switch S2) to output side of
monitor switch S9.
T9 Connects channel B input (U2 pin 8) to input side of monitor switch 9.
T10 Connects channel B final output (Just prior to -10/+4 switch S2) to output side of
monitor switch S9.
T11 Connects the slave gain reduction LEDs to the stereo/dual switch.
Alesis 3630 Compressor Service Manual 1.00 4 12/11/02

4.00 Test Procedures
Testing the 3630 or NanoCompressor can be as simple as plugging the unit in to an
audio source and listening to the outputs for distortion while changing settings. In the interest of
being thorough, the full QC procedure for the 3630 is presented below. The full test requires a
distortion analyzer to complete it. Test procedures are identical for both channels. Bearing in
mind the obvious limitations of the NanoCompressor, (i.e. no noise gate or stereo/dual
operation), the same test procedure can be used.
4.10 Distortion Adjustments
✔ Connect equipment to channel A and establish settings as shown in Figure 2.
✔ Set Distortion Analyzer to 1KHz, 1V output.
✔ Adjust the output level of the distortion analyzer until all of the YELLOW INPUT/OUTPUT
LEDs are ON.
✔ Adjust the trimpot (Channel A-R24, Channel B-R49) for the lowest distortion possible. The
specification for this adjustment is 0.08%. Any value above this indicates that further
troubleshooting may be required.
✔ Change the frequency control of the distortion analyzer to 100Hz.
✔ Press the PEAK/RMS switch IN.
✔ Rotate the compression THRESHOLD knob until 7 red GAIN REDUCTION LEDs are ON.
✔ Adjust the trimpot (Channel A-R7, Channel B-R49) for the lowest distortion possible. The
specification for this adjustment is 0.6%. Any value above this indicates that further
troubleshooting may be required.
Figure 2-QC Test Setup
Alesis 3630 Compressor Service Manual 1.00 5 12/11/02

4.20 Input/Output Level Test
✔ Connect equipment to channel A and set all knobs and switches according as shown in
Figure 3.
✔ Set Distortion Analyzer to 1KHz, 1V output.
✔ Adjust the output level of the distortion analyzer until all of the YELLOW INPUT/OUTPUT
LEDs are ON.
✔ Press the INPUT/OUTPUT switch OUT. The LEDs should stay the same.
✔ Set the distortion analyzer frequency to 20KHz. 2 or 3 of the YELLOW INPUT/OUTPUT
LEDs should be ON.
✔ Set the distortion analyzer frequency to 20Hz. 2 or 3 of the YELLOW INPUT/OUTPUT LEDs
should be ON.
✔ Set Distortion Analyzer to 1KHz.
✔ Press the BYPASS/COMP switch OUT.
✔ Rotate the OUTPUT knob until all of the YELLOW INPUT/OUTPUT LEDs are on.
✔ Change the distortion analyzer to 0.3V output level. 5 GREEN INPUT/OUTPUT LEDs should
be on.
✔ Change the distortion analyzer to 0.1V output level. 3 GREEN INPUT/OUTPUT LEDs should
be on.
Figure 3-QC Test Setup
Alesis 3630 Compressor Service Manual 1.00 6 12/11/02

4.30 Function Test
✔ Connect equipment to channel A and establish settings as shown in Figure 3.
✔ Set the distortion analyzer for 1KHz, 0.3V output.
✔ Rotate the OUTPUT knob CW. All INPUT/OUTPUT LEDs should be on.
✔ Rotate the OUTPUT knob slowly CCW. The INPUT/OUTPUT LEDs should turn off 1 at a
time. (Two or more turning off at the same time may indicate a faulty comparator or a short
between traces.)
✔ Set the OUTPUT knob to center position.
✔ Rotate the compression THRESHOLD knob CCW. All red GAIN REDUCTION LEDs should
be on, and all INPUT/OUTPUT LEDs should be off.
✔ Rotate the RATIO knob CW.
✔ Rotate the RELEASE knob CW.
✔ Quickly rotate the compression THRESHOLD knob CW. The red GAIN REDUCTION LEDs
should slowly turn off.
✔ Press the PEAK/RMS switch OUT.
✔ Rotate the compression THRESHOLD knob CCW. All red GAIN REDUCTION LEDs should
be on. Then quickly rotate the compression THRESHOLD knob CW. The red GAIN
REDUCTION LEDs should quickly turn off.
✔ Rotate the RELEASE knob CCW.
✔ Rotate the compression THRESHOLD knob until only 1 red GAIN REDUCION LED is on.
✔ Press the HARD KNEE/SOFT KNEE switch to out. 5 or 6 red GAIN REDUCTION LEDs
should be on.
✔ Set the distortion analyzer for 0.1V output level.
✔ Rotate the GATE THRESHOLD knob CW. The green OPEN LED should quickly turn off at
the same time that the red CLOSE LED quickly turns on.
✔ Rotate the gate RATE knob CW. Rotate the gate THRESHOLD knob CCW.
✔ Rotate the gate THRESHOLD knob CW. The green OPEN LED should turn slowly off at the
same time the red CLOSED LED turns slowly on.
4.40 Stereo Mode Test
✔ Connect equipment to Channel B and establish settings as shown in Figure 3.
✔ Set the distortion analyzer for 1KHz, 0.3V output.
✔ Press the STEREO LINK/DUAL MONO switch IN.
✔ Rotate Channel A compression THRESHOLD CCW. All channel A and B GAIN REDUCTION
LEDs should be on.
✔ Set the distortion analyzer for a 0.1V output level.
✔ Rotate the channel A gate THRESHOLD knob CW. The channel A and B OPEN LEDs
should go off, and the channel A and B CLOSE LEDs should be on.
Alesis 3630 Compressor Service Manual 1.00 7 12/11/02

4.50 Final Test
✔ Connect equipment and establish settings as shown in Figure 4.
✔ Listen for noise or distortion.
✔ Press the PEAK/RMS switch IN and OUT. Listen for noise.
✔ Press the HARD KNEE/SOFT KNEE switch IN and OUT. Listen for noise.
✔ Press the BYPASS/COMP switch IN and OUT. Listen for noise.
✔ Rotate the THRESHOLD knob CCW. The volume should drop a little. Listen for noise.
✔ Rotate the output knob CW. Volume should increase. Again, listen for noise.
Figure 4-QC Test Setup
Alesis 3630 Compressor Service Manual 1.00 8 12/11/02

5.00 Troubleshooting
Symptom Possible Failure and Solution
Unit is dead. No LEDs, no audio. AC adapter is bad. Check adapter for 9VAC
output and replace if necessary.
Broken PS input jack. Check and replace if
necessary.
In 3630, the ribbon cable between the main
PCB and the LED PCB (J5 to J9) is
disconnected. Check and reseat if necessary.
Faulty component in Power supply circuitry.
Particularly check electrolytic capacitors C1,
C2, C25, and C34, diodes D1-D4, and
regulators U1 and U8.
(3630 Only) All Gain Reduction LEDs are on U18 on LED PCB had failed. Check and
replace if necessary.
6.00 Updates And Corrections
Unless otherwise noted, all changes are incorporated into subsequent PCB revisions.
6.10 3630 Changes
6.11 Revision B Main PCB Distortion Reduction.
It was found that distortion while compression is off in the hard knee setting could be
improved by adding a ground jumper on the solder side of the PCB between the ground at the
power supply input jack
and the ground point of the
ratio potentiometer.
Additionally R76 and R99
should be changed from
1K to 1.5K (Part No. 0-00-
0152) and two 150Ωand
two 10K resistors added
(See Figure 5 for details).
Note that this change was
done largely at the factory
and it is extremely unlikely
that you will ever see a unit
without it. It is included
here for the sake of
completeness.
Figure 5 -Added Resistors
Alesis 3630 Compressor Service Manual 1.00 9 12/11/02

Alesis 3630 Compressor Service Manual 1.00 10 12/11/02
6.12 Power Up Oscillation
It was found that some units go
into oscillation at power up. The
addition of a 0.1µF capacitor (Part No.
1-02-0104) between the collector of Q6
and -15V (See Figure 6) eliminates
this.
6.13 Revision C Main PCB
Dual/Stereo Switch Noise
It was found that some units had
an audible “pop” when switching
between Dual and Stereo modes.
Adding a 1K resistor between Pin 2 of
U7 and Ground eliminates the popping
sound.
6.20 NanoCompressor Changes
6.21 Revision B Main PCB Right Channel Sensing Resistor
In the original design only the left
channel was used for compression
detection. This change mixes the right
channel audio into the sensor circuitry in
order to ensure that compression takes
place in the event of material passing
through the right channel only. The
change consists of soldering a 2K (Part
No. 0-00-0202) resistor between pin 8 of
[U2] and the left side of [R22] (See Figure
7 for details). Note that this change was
done largely at the factory and it is
extremely unlikely that you will ever see a
unit without it. It is included here for the
sake of completeness.
Figure 6 - Oscillation Elimination Capacitor Location
Figure 7 - Channel Sensing Resistor Location

6.22 Revision C Right Channel Normalization
Two cuts and two jumpers were installed
to correct a normalization error in Revision C
PCBs (See Figures 8 and 9 for details). Note that
this change was done largely at the factory and it
is extremely unlikely that you will ever see a unit
without it. It is included here for the sake of
completeness.
Figure 8-Revision C Cuts
Figure 9-Revision C Jumpers
6.23 Improvement of High Frequency Phase Response
C5 and C14 should be changed from a 1500pF monoblock capacitor to a 470pF
monoblock (Part No. 1-21-4714).
6.24 Improvement of Power Supply Stability Under High Output Loading
It was found that under high output loading (i.e. the output voltage of the unit swings close
to the limits set by the power supply, and current demands are at maximum) the supply began to
contain significant amounts of ripple voltage which could cause excess distortion of the audio
output. To cure this, the power supply filter capacitor [C2] was changed from 100µF to 220µF.
Alesis 3630 Compressor Service Manual 1.00 11 12/11/02

7.00 Service Parts List
7.10 3630 Service Parts List
Alesis 3630 Compressor Service Manual 1.00
GRP DESCRIPTION ALPARTNO QTY POSITION PCB
ASSY PCB, MAIN ASSEMBLY 8-20-0016 1 MAIN BOARD
ASSY PCB, LED ASSEMBLY 8-20-0017 1 LED BOARD
CAB 20 PIN DIL 4 IN 0.1 CTR 4-18-0420 1 J5,J9 LED
CAP 22 MF ELEC 25V 1-09-0022 4 C11,29,43,55 MAIN
CAP 10 MF ELEC 25V 1-09-0100 4 C9,16,27,33 MAIN
CAP 1.0 MF ELEC 25V 4x7mm 1-09-0105 10 C8,17,19-21,24-26,34,48 MAIN
CAP 4.7 MF ELEC 25V 4x7mm 1-09-0475 22 C6,7,14,22,23,36,41,46,47,49,54,59,60,62-70 MAIN
CAP 1000 MF ELEC 25V 10x20 1-09-1000 4 C2-5 MAIN
CER 0.1 MF CERDISC 1-02-0104 8 C1,42,44,45,56-58,LED PCB MAIN
CER 150 PF CERDISC 1-02-0151 4 C12,13,30,31 MAIN
CER 1500 PF CERDISC 1-02-0152 2 C18,35 MAIN
CER 0.22 MF CERDISC 1-02-0223 2 C37,51 MAIN
CER 0.047 MF CERDISC 1-02-0473 6 C38,39,50,52,71,72 MAIN
CER 56 PF CERDISC 1-02-0560 4 C10,15,28,32 MAIN
CER 0.47 MF CERDISC 1-02-1474 2 C40,53 MAIN
HDR 20 PIN DIL 0.1 CTR 4-14-0020 2 J5,9 MAIN
HDW 6-32x1/4 PP BLK UNC 5-00-0003 2 VR1,VR2 MAIN
HDW M-3x7mm PHILSLOT 5-00-0020 6 CASE
HDW #6 INT STAR WASHER 5-01-0002 2 VR1,VR2 MAIN
HDW #6 FLAT WASHER 5-01-0003 6 J2-4,J6-8 MAIN
HDW 6-32x1/2 STANDOFF 5-02-0003 2 VR1,VR2 MAIN
HDW SOLDER LUG PCB MNT 9-03-1036 6 J2-4,J6-8
IC 7815 +15V REG TO220 2-11-7815 1 VR1 MAIN
IC 7915 -15V REG TO220 2-11-7915 1 VR2 MAIN
IC LF347 QUAD OP-AMP 2-21-0347 3 U2,4,6 MAIN
IC 2150A VCA 2-21-2150 2 U3,7 MAIN
IC LM339 QUAD COMP 2-22-0339 17 U8-24 LED
IC 2252 RMS DETECTOR 2-30-2252 2 U1,5 MAIN
JAC 1/4 CLIFF (MONO) 4-02-0001 4 J2,4,6,8 MAIN
JAC 1/4 CLIFF (STER) 4-03-0001 2 J3,7 MAIN
JAC 3.5mm BAR JACK (P3) 4-16-0002 1 J1 (POWER, 2.5mm CTR) MAIN
ME 1N4148 SIGNAL DIODE 2-00-4148 8 D5,6,8-10,12-14 MAIN
ME 1N4003 POWER DIODE 2-01-4001 4 D1-4 MAIN
ME 1N5231B ZENER DIODE 2-02-5231 2 D21,22 LED
ME 2N4403 PNP TRANS 2-04-4403 10 Q1-10 LED
ME LED (GRN) 1151 T1 3-00-0001 14 LED
ME LED (YEL) 1131 T1 3-01-0001 6 LED
ME LED (RED) 1102 T1 3-02-0001 32 LED
ME DPDT SLIDE SWITCH 6-01-0002 2 S2,3 (GAIN) MAIN
ME DPDT SWITCH 6-02-0001 8 S9-12,4,5,7,8 (FUNCT) LED
ME DPDT SWITCH (CL\QS) 6-02-0003 1 S1 (POWER) MAIN
ME 6PDT SWITCH 6-02-0005 1 S6 (LINK) MAIN
MIS FOAM STRIP 0.3x7.5 9-23-1014 4 FRONT PANEL
GRP DESCRIPTION ALPARTNO QTY POSITION PCB
MTL RACK EAR 100mm 9-58-1009 2
12 12/11/02

MTL FRONT PANEL 9-02-1005 1
MTL CASE 100mm 9-03-1048 1
PCB PCB, MAIN REV C 9-40-1036 1 MAIN
PCB PCB, LED REV C 9-40-1037 1 LED
PLS SWITCH XTENDER 70mm 9-15-0012 1 S1 (POWER)
PLS KNOB 15x20mm 9-15-0043 14 R119-132
PLS SWITCH XTENDER 20mm 9-15-0044 8 S4,5,7-12
PLS FRONT PANEL BEZEL REV B 9-15-0045 2
PLS SWITCH XTENDER 9-15-0056 1 S6
POT 50K TRIMPOT 0-08-0503 4 R7,24,49,66 MAIN
POT 2MA SINGLE 0-09-1003 2 R122,129 MAIN
POT 10KA SINGLE 0-09-1005 2 R124,131 MAIN
POT 10KB SINGLE 0-09-1006 4 R119,123,126,130 MAIN
POT 1MA SINGLE 0-09-1007 4 R121,125,128,132 MAIN
POT 1KB SINGLE 0-09-1014 2 R120,127 MAIN
RES 0 OHM 1/8W 5% 0-00-0000 119 0.3"(83),0.5"(36) MAIN/LED
RES 100 OHM 1/8W 5% 0-00-0101 8 R29,71,86,113,147,150,185,188 MAIN/LED
RES 1K OHM 1/8W 5% 0-00-0102 12 R2,14,21,32,36,44,56,63,83,106,153,191 MAIN/LED
RES 10K OHM 1/8W 5% 0-00-0103 12 R8,50,85,90,91,95,110,111,114,117,214,217 MAIN
RES 10K OHM 1/8W 5% 0-00-0103 12 R134,136,137,162,167-171,174,175,200 LED
RES 100K OHM 1/8W 5% 0-00-0104 10 R12,18,37,38,54,60,77,100,206,207 MAIN/LED
RES 1M OHM 1/8W 5% 0-00-0105 6 R10,35,52,82,89,105 MAIN
RES 150 OHM 1/8W 5% 0-00-0151 2 R215,216 MAIN
RES 1.5K OHM 1/8W 5% 0-00-0152 2 R76,99 MAIN
RES 150K OHM 1/8W 5% 0-00-0154 4 R27,69,208,211 MAIN
RES 18K OHM 1/8W 5% 0-00-0183 2 R88,109 MAIN
RES 20 OHM 1/8W 5% 0-00-0200 2 R5,47 MAIN
RES 2K OHM 1/8W 5% 0-00-0202 20 R11,53,141-146,154,165,166,179-184,192,203,204 MAIN/LED
RES 20K OHM 1/8W 5% 0-00-0203 8 R16,58,94,116,135,163,173,201 MAIN/LED
RES 2.2K OHM 1/8W 5% 0-00-0222 6 R13,20,42,55,62,72 MAIN
RES 22K OHM 1/8W 5% 0-00-0223 2 R22,64 MAIN
RES 22M OHM 1/8W 5% 0-00-0226 2 R4,46 MAIN
RES 270 OHM 1/8W 5% 0-00-0271 2 R33,34 MAIN
RES 3K OHM 1/8W 5% 0-00-0302 4 R17,59,75,98 MAIN
RES 30K OHM 1/8W 5% 0-00-0303 4 R78,87,101,118 MAIN
RES 33 OHM 1/8W 5% 0-00-0330 4 R79,102,209,212 MAIN
RES 3.3K OHM 1/8W 5% 0-00-0332 6 R81,103,155,157,193,195 MAIN/LED
RES 3.9K OHM 1/8W 5% 0-00-0392 2 R158,196 LED
RES 47 OHM 1/8W 5% 0-00-0470 2 R28,70 MAIN
RES 470 OHM 1/8W 5% 0-00-0471 6 R19,26,61,68,210,213 MAIN
RES 4.7K OHM 1/8W 5% 0-00-0472 11 R31,39,40,92,93,108,112,115,156,194,205 MAIN/LED
RES 47K OHM 1/8W 5% 0-00-0473 8 R9,51,148,149,164,186,187,202 MAIN/LED
RES 5.1K OHM 1/8W 5% 0-00-0512 4 R25,67,159,197 MAIN/LED
RES 560 OHM 1/8W 5% 0-00-0561 4 R30,96,152,190 MAIN/LED
RES 560K OHM 1/8W 5% 0-00-0564 2 R3,45 MAIN
RES 620 OHM 1/8W 5% 0-00-0621 2 R80,104 MAIN
GRP DESCRIPTION ALPARTNO QTY POSITION PCB
RES 6.2K OHM 1/8W 5% 0-00-0622 14 R15,41,57,73,74,97,138-140,160,176-178,198 MAIN/LED
RES 680 OHM 1/8W 5% 0-00-0681 2 R151,189 LED
RES 6.8K OHM 1/8W 5% 0-00-0683 2 R1,43 LED
Alesis 3630 Compressor Service Manual 1.00 13 12/11/02

RES 8.2K OHM 1/8W 5% 0-00-0822 6 R84,107,133,161,172,199 MAIN/LED
RES 20K OHM 1/8W 1% 0-02-0203 2 R23,65 MAIN
RES 22K OHM 1/8W 1% 0-02-0223 2 R22,64 MAIN
7.20 NanoCompressor Service Parts List
GRP DESCRIPTION ALPARTNO QTY POSITION
ASY ASSY KNOB NANO-SERIES NV/NC 9-96-1276 5
ASY ASSY PCB MAIN NC 9-79-1301 1 PCB
CAP CAP 0.1uF CERDISC 10% .30"DIA. 50V 1-02-0104 8 C4, C15-16, C18, C24, C29, C33, C35
CAP CAP 150PF CERDISC 10% 1-02-0151 2 C3, C6
CAP CAP 22uF ELEC 25V 1-09-0022 2 C20, C31
CAP CAP 10uF ELEC 25V 1-09-0100 2 C7, C11
CAP CAP 1.0uF ELEC 25V 1-09-0105 4 C8, C10, C13, C17
CAP CAP 220uF ELEC 25V 1-09-0221 2 C1, C2
CAP CAP 4.7uF ELEC 50V 20% 05x11 1-11-0407 3 C9, C12, C30
CAP CAP 220uF ELEC 50V .20"-LEAD 1-12-0226 2 C25, C34
CAP CAP 0.1uF MONO 50V RADIAL 1-21-0104 1 C32
CAP CAP 1500PF MONO 50V 1-21-0152 2 C21-22
CAP CAP 0.22uF MONO 50V 1-21-0223 1 C28
CAP CAP 56PF MONO 50V 1-21-0560 1 C19
CAP CAP 0.47uF MONO 50V 1-21-1474 1 C26
CAP CAP 471PF MONO 50V 1-21-4714 2 C5, C14
DIO DIODE SIGNAL 1N4148 2-00-4148 1 D5
DIO DIODE POWER 1N4003 2-01-4003 4 D1-4
FIL CAP 0.047uF FILM 5% 1-20-0473 3 C23, C27, C36
IC IC TL082 TEXAS INSTRUMENTS 2-21-0082 1 U7
IC IC TL084 QUAD OPAMP TI 2-21-0084 1 U2
IC IC 2150A VCA DBX 2-21-2150 2 U4-5
IC IC 2252 RMS DETECTOR DBX 2-30-2252 1 U3
IC REG 7815 +15V TO220 NATIONAL 2-11-7815 1 U8
IC REG 7915 -15V TO220 NATIONAL 2-11-7915 1 U1
IC IC LM339 QUAD COMP NATIONA 2-22-0339 5 U6, U9-12
JAC JACK ¼ MONO CLIFF 4-02-0001 4 J3-6
JAC JACK ¼ STEREO (CL1239LK) 4-03-0001 1 J2
JAC JACK 3.5MM BARREL (P3) 4-16-0002 1 J1
LED LED GRN T1 3-00-0001 4 D9-11, D18
LED LED YEL T1 3-01-0001 2 D7-8
LED LED RED T1 3-02-0001 7 D6, D12-17
LIT MANUAL REFERENCE NC 7-51-1205 1
MIS GASKET FACEPLATE NC 9-13-1043 1
MTL COVER (TOP/SID22E) NANO-SERIES 9-03-1188 1
MTL PANEL SUB NC 9-03-1233 1
GRP DESCRIPTION ALPARTNO QTY POSITION
MTL CHASSIS MAIN NC (BTM/SIDE/BACK) 9-03-1234 1
MTL LUG SOLDER PCB MNT 9-03-1036 5 J2-6
PLS EXTENDER SWITCH NC 9-15-0134 4
PLS FACEPLATE NC 9-15-1307 1
POT POT TRIM 50K 0-08-1503 3 R10, R27-28
Alesis 3630 Compressor Service Manual 1.00 14 12/11/02

POT POT 2MA SINGLE CONTROL 0-09-1003 1 R82
POT POT 10KB SINGLE CONTROL PCB-MNT
18mm-SHFT
0-09-1006 2 R79, R88
POT POT 1MA SINGLE CONTROL 0-09-1007 1 R83
POT POT 1KB SINGLE CONTROL 0-09-1014 1 R85
RES RES 100 OHM 1/8W 5% 0-00-0101 4 R34, R42, R44, R49
RES RES 1K OHM 1/8W 5% 0-00-0102 6 R2-3, R14, R25, R64, R68
RES RES 10K OHM 1/8W 5% 0-00-0103 4 R15, R53, R57, R80
RES RES 100K OHM 1/8W 5% 0-00-0104 2 R46, R59
RES RES 1M OHM 1/8W 5% 0-00-0105 4 R1, R6, R19, R54
RES RES 12K OHM 1/8W 5% 0-00-0123 1 R67
RES RES 150 OHM 1/8W 5% 0-00-0151 1 R29
RES RES 1.5K OHM 1/8W 5% 0-00-0152 1 R58
RES RES 150K OHM 1/8W 5% 0-00-0154 6 R31-32, R38, R41, R55, R73, R92
RES RES 16K OHM 1/8W 5% 0-00-0163 2 R65, R75
RES RES 20 OHM 1/8W 5% 0-00-0200 1 R16
RES RES 2K OHM 1/8W 5% 0-00-0202 6 R22, R86, U2(8) TO LEFT-SIDE-OF-R22, R89-91
RES RES 20K OHM 1/8W 5% 0-00-0203 2 R45, R74
RES RES 2.2K OHM 1/8W 5% 0-00-0222 4 R7, R21, R48, R77
RES RES 22K OHM 1/8W 5% 0-00-0223 2 R18, R81
RES RES 22M OHM 1/8W 5% 0-00-0226 1 R12
RES RES 3K OHM 1/8W 5% 0-00-0302 3 R26, R30, R63
RES RES 30K OHM 1/8W 5% 0-00-0303 3 R52, R66, R72
RES RES 33 OHM 1/8W 5% 0-00-0330 3 R33, R37, R40
RES RES 3.3K OHM 1/8W 5% 0-00-0332 2 R51, R69
RES RES 47 OHM 1/8W 5% 0-00-0470 2 R35, R39
RES RES 470 OHM 1/8W 5% 0-00-0471 4 R5, R11, R62, R84
RES RES 47K OHM 1/8W 5% 0-00-0473 4 R17, R50, R60-61
RES RES 5.1K OHM 1/8W 5% 0-00-0512 3 R20, R24, R76
RES RES 560K OHM 1/8W 5% 0-00-0564 1 R13
RES RES 620 OHM 1/8W 5% 0-00-0621 1 R56
RES RES 6.2K OHM 1/8W 5% 0-00-0622 1 R9, R23, R78
RES RES 6.8K OHM 1/8W 5% 0-00-0682 2 R70, R87
RES RES 75K OHM 1/8W 5% 0-00-0753 1 R71
RES RES 9.1K OHM 1/8W 5% 0-00-0912 1 R47
RES RES 20.0K OHM 1/8W 1% 0-01-2002 2 R36, R43
RES RES 5.11K OHM 1/8W 1% 0-01-5111 2 R4, R8
RUB FOOT RUBBER NANO-SERIES 9-23-1071 1 (SET OF 4 FEET)
SWT SWITCH DPDT 5mm 6-02-0013 4 S1-4
TRN TRANS 2N4403 PNP 2-03-4403 4 Q1-4
Alesis 3630 Compressor Service Manual 1.00 15 12/11/02