BOSSCO AC-3 Operating and maintenance manual

SERVICE NOTES
Issued by RJA
Copyright © 2006 ROLAND CORPORATION
All rights reserved. No part of this publication may be reproduced in any form without the written permission
of ROLAND CORPORATION.
Printed in Japan (0500) (SC-KWS)17058403E0
Mar. 2006 AC-3
LEVEL
REVERB
INPUT
LINE OUT
G.AMP OUT
Table of Contents
Cautionary Notes ..............................................................2
Specifications .....................................................................2
Location of Controls .........................................................3
Location of Controls Parts List........................................3
Exploded View ..................................................................4
Exploded View Parts List.................................................4
Parts List .............................................................................5
Checking Version Number ..............................................8
Test Mode ...........................................................................8
Circuit Board....................................................................13
Circuit Diagram...............................................................14

2
Mar. 2006 AC-3
Cautionary Notes
Before beginning the procedure, please read
through this document.
No User Data
This product cannot save user data. Backing up user data during servicing is
not required.
Parts List
A component whose part code is ******** cannot be supplied as a service part
because one of the following reasons applies.
• Because it is supplied as an assembled part (under a different part code).
• Because a number of circuit boards are grouped together and supplied as
a single circuit board (under a different part code).
• Because supply is prohibited due to copyright restrictions.
• Because reissuance is restricted.
• Because the part is made to order (at current market price).
Part Replacement
When replacing components near the power-supply circuit or a heat-
generating circuit (such as a circuit provided with a heat sink or including a
cement resistor), carry out the procedure according to the instructions with
respect to the part number, direction, and attachment position (mounting so as
to leave an air gap between the component and the circuit board, etc.).
Circuit Diagram
In the circuit diagram, ‘NIU’ is an abbreviation for ‘NOT IN USE’. The circuit
board and circuit-board diagram show silkscreened indications, but no
components are mounted.
Specifications
AC-3: Acoustic Simulator
Nominal Input Level
20 dBu
Input Impedance
1 MΩ
Nominal Output Level
20 dBu
Output Impedance
1 kΩ
Recommended Load Impedance
10 kΩor greater
Controls
Pedal switch, LEVEL knob, REVERB knob, BODY knob, TOP knob, MODE
knob
Indicators
CHECK indicator (Serves also as battery check indicator)
Connectors
INPUT jack, LINE OUT jack, G.AMP OUT jack, AC adaptor jack (DC 9 V)
Power Supply
DC 9 V: Dry battery/9 V type (6F22 (carbon), 6LR61 (alkaline)), AC Adaptor
(PSA-series: optional)
Current Draw
39 mA (DC 9 V)
* Expected battery life under continuous use:
Carbon: 3 hours, Alkaline: 10 hours
These figures will vary depending on the actual conditions of use.
Dimensions
73 (W) x 129 (D) x 59 (H) mm
2-7/8 (W) x 5-1/8 (D) x 2-3/8 (H) inches
Weight
440 g /1 lb (including battery)
Accessories
Owner’s Manual English (#G6027114R0)
Leaflet (“USING THE UNIT SAFELY,” “IMPORTANT NOTES,” and
“Information”) (#********)
Dry battery/9 V type (6LR61) (#********)
* The battery that was supplied with the unit is for temporary use intended
primarily for testing its operation. We also suggest replacing this with an
alkaline dry cell.
Option
AC Adaptor (PSA-series)
* 0 dBu = 0.775 Vrms
* In the interest of product improvement, the specifications and/or appearance of
this unit are subject to change without prior notice.

3
Mar. 2006 AC-3
Location of Controls
fig.panel.eps
Location of Controls Parts List
LEVEL
REVERB
INPUT
LINE OUT
G.AMP OUT
10
9
8
7
6
5
4
3
2
1
14 13 12 11
No. Part Code Part Name Description Q’ty
1 22480220R0 P R-KNOB BF BLK/LCG (INTERNAL) 1
22480221R0 P R-KNOB S BLK/LCG (EXTERNAL) 1
F3279854R0 POTENTIOMETER RD912D-20-20FWH-B54-6009 1
H5039521R0 NUT M7 4
2 F3449707R0 LINE OUT JACK HTJ-064-12DS 1
H5039510R0 NUT M9X12X2T NI 4
H5039112R0 WASHER 9X14X0.5 NI 4
3 13449140R0 JACK (STEREO) HTJ-064-14D 1
H5039510R0 NUT M9X12X2T NI 4
H5039112R0 WASHER 9X14X0.5 NI 4
4 75D932T0R0 PEDAL 1
5 22357304R0 PEDAL PLATE 1
6 H5029820R0 THUMB SCREW 3X10 FEBC 1
7 13449104R0 INPUT JACK HTJ-064-13D 1
H5039510R0 NUT M9X12X2T NI 4
H5039112R0 WASHER 9X14X0.5 NI 4
8 F3279853R0 POTENTIOMETER RD901-20-15FP-B54K-04 1
22480260R0 P R-KNOB MF BLK/LCG 3
H5039521R0 NUT M7 4
9 F3279852R0 POTENTIOMETER RD901-20-15FW-B54-006 2
22480260R0 P R-KNOB MF BLK/LCG 3
H5039521R0 NUT M7 4
10 G2217758R0 PANEL 1
11 75D933C0R0 CASE 1
12 15029281R0 LED L-34HDSL 1
13 13449717R0 ADAPTOR JACK HEC2392-01-150 1
14 22537538R0 PSA LABEL 8X13 1

4
Mar. 2006 AC-3
Exploded View
fig.exploded.eps
Exploded View Parts List
11
10
b
b
a
a
2
12 19
d
8
3
c
7
6
5
4
No. Part Code Part Name Description Q’ty
1 13129710R0 SWITCH (PUSH) JM-0404 1
2 22267333R0 CUSHION 1
3 F3419102R0 BATTERY CONNECTOR 006P BATTERY SNAP 1
4 G2537516R0 PSA CAUTION CE 9V N225 1
5 22357305R0 BOTTOM BASE 1
6 22027851R0 BOTTOM COVER 1
7 G2167301R0 INSULATING SHEET 1
8 22157702R0 PEDAL GUIDE BUSH 1
9 22177109R0 COIL SPRING 1
10 22357304R0 PEDAL PLATE 1
11 75D932T0R0 PEDAL 1
12 75D933C0R0 CASE 1
a H5039401R0 NYLON WASHER M3X6X0.5 2
b H5019413R0 SCREW M3X10 BINDING MACHINE FEBC 2
c H5029325R0 SCREW 3X6 B1FEBC 4
d H5029820R0 THUMB SCREW 3X10 FEBC 1

5
Mar. 2006 AC-3
Parts List
fig.part1j
SAFETY PRECAUTIONS:
The parts marked have
safety-related characteristics. Use
only listed parts for replacement.
NOTE: The parts marked # are new. (initial parts)
Due to one or more of the following reasons,
parts with parts code ******** cannot be supplied as service parts.
• Part supplied only as a component in a complete assembly
• Copyright does not permit the part to be supplied
• Part is sold commercially
The description "Q'TY" means a necessary number of the parts per one product.
CASING
# 22357305R0 BOTTOM BASE 1
# 22027851R0 BOTTOM COVER 1
# 75D933C0R0 CASE 1
# G2217758R0 PANEL 1
# 75D932T0R0 PEDAL 1
# 22357304R0 PEDAL PLATE 1
KNOB, BUTTON
# 22480221R0 P R-KNOB S BLK/LCG (EXTERNAL) 1
# 22480260R0 P R-KNOB MF BLK/LCG 3
# 22480220R0 P R-KNOB BF BLK/LCG (INTERNAL) 1
SWITCH
# 13129710R0 SWITCH (PUSH) JM-0404 SW1 1
JACK, EXT TERMINAL
13449140R0 JACK (STEREO) HTJ-064-14D 1
# 13449104R0 INPUT JACK HTJ-064-13D 1
# F3449707R0 LINE OUT JACK HTJ-064-12DS JK4 1
# 13449717R0 ADAPTOR JACK HEC2392-01-150 JK6 1
PWB ASSY
# 75D933P0R0 PWB ASSY 1
# 22917496R0 PWB LED#496 1
IC
# F5289709R0 BD45301G IC (RESEST) IC8 1
# 15189261 M5218AFP-600E IC (OP AMP) IC1, IC3, IC4 3
# F5289101R0 NJM2100M IC (OP AMP) IC2 1
# F5259710R0 TC7W04FK IC (LOGIC) IC10 1
# F5259708R0 UPD800402GJ-211-UEN-A
(0401099
IC (ESC) IC7 1
# F5279884R0 HN58X24512I (04231223) IC (EEPROM) IC6 1
# F5269707R0 DC-DC BD9851EFV IC (DC-DC) IC9 1
# F5209129R0 AK4552VT 24BIT IC (CODEC) IC5 1
HYBRID
# F5329540R0 QS5U27 FET AND DIODE Q15, Q16 2
TRANSISTOR
# F5309603R0 2SA1832GR (TE85L F) TRANSISTOR Q13 1
# F5129405R0 2SC4738GR (TE85L F) TRANSISTOR Q7, Q8, Q9, Q10, Q11, Q12, Q17 7
# F5329530R0 2SK879Y-TE85R FET Q1, Q2, Q4, Q5 4
# 15329103R0 2SK880GR-TE85R FET Q3 1
DIODE
# 15029281R0 L-34HDSL LED 1
# F5339505R0 1SS387 (TPH3 F) DIODE D1, D2, D3, D4 4
# F5339201R0 GS1G DIODE D6 1
# F5339137R0 SS14 VF 0.45V DIODE D5 1
RESISTOR
# F5399101R0 0J (1608TYPE) MTL.FILM RESISTOR R22, R92, R94, R132, R133, R134, R135, R136 8
# F5399115R0 100J (1608TYPE) MTL.FILM RESISTOR R26, R48, R138, R139, R140 5
# F5399170R0 100KJ (1608TYPE) MTL.FILM RESISTOR R14, R34, R51, R52, R53, R55, R95 7
# F5399104R0 10J (1608TYPE) MTL.FILM RESISTOR R23 1
# F5429365R0 10KF 1PCT (1608TYPE) F-RANK MTL.FILM RESISTOR R29, R47, R60, R74, R114, R115, R119, R121 8
# F5399140R0 10KJ (1608TYPE) MTL.FILM RESISTOR R15, R19, R87, R88, R91, R98, R99, R100,
R102, R126, R127, R128, R129
13

6
Mar. 2006 AC-3
# F5399918R0 12KF 1PCT (1608TYPE) F-RANK MTL.FILM RESISTOR R77 1
# F5429386R0 150KF 1PCT (1608TYPE) F-
RANK
MTL.FILM RESISTOR R39 1
# F5429366R0 15KF 1PCT (1608TYPE) F-RANK MTL.FILM RESISTOR R117 1
# F5399147R0 15KJ (1608TYPE) MTL.FILM RESISTOR R12, R16, R36 3
# F5429371R0 18KF 1PCT (1608TYPE) F-RANK MTL.FILM RESISTOR R108 1
# F5399128R0 1KJ (1608TYPE) MTL.FILM RESISTOR R11, R31, R58, R69, R73, R96 6
# F5399200R0 1M J (1608TYPE) MTL.FILM RESISTOR R1, R13, R18, R20, R33, R49, R54, R56, R57 9
# F5399130R0 2.2KJ (1608TYPE) MTL.FILM RESISTOR R75 1
# F5429373R0 22KF 1PCT (1608TYPE) F-RANK MTL.FILM RESISTOR R112 1
# F5399152R0 22KJ (1608TYPE) MTL.FILM RESISTOR R3, R7, R25, R43, R59, R80, R144 7
# F5429372R0 27KF 1PCT (1608TYPE) F-RANK MTL.FILM RESISTOR R122, R116 2
# F5429346R0 3.3KF 1PCT (1608TYPE) F-
RANK
MTL.FILM RESISTOR R103 1
# F5399141R0 3.9KJ (1608TYPE) MTL.FILM RESISTOR R142 1
# F5399294R0 39J (1608TYPE) MTL.FILM RESISTOR R105 1
# F5399157R0 39KJ (1608TYPE) MTL.FILM RESISTOR R79 1
# F5399133R0 4.7KJ (1608TYPE) MTL.FILM RESISTOR R2, R5, R9, R21, R24, R27, R143 7
# F5429375R0 47KF 1PCT (1608TYPE) F-RANK MTL.FILM RESISTOR R107, R113 2
# F5399158R0 47KJ (1608TYPE) MTL.FILM RESISTOR R4, R6, R28, R35, R106, R109, R111, R118 8
# F5429350R0 5.6KF 1PCT (1608TYPE) F-
RANK
MTL.FILM RESISTOR R104 1
# F5399108R0 56J (1608TYPE) MTL.FILM RESISTOR R120, R110 2
# F5399160R0 56KJ (1608TYPE) MTL.FILM RESISTOR RR8, R17, R32, R44, R45, R46, R50, R61, R62,
R63, R64, R76, R123
13
RESISTOR
POTENTIOMETER
# F3279853R0 RD901-20-15FP-B54K-04 POTENTIOMETER VR4 1
# F3279852R0 RD901-20-15FW-B54-006 POTENTIOMETER VR2, VR3 2
# F3279854R0 RD912D-20-20FWH-B54-6009 POTENTIOMETER VR1 1
CAPACITOR
# F5349704R0 ECPU1E474KB5 (04013567) MYLAR CAPACITOR C12 1
# F5379004R0 10UF GRM31MF51A106ZA01L CHIP CAPACITOR (3216TYPE) C1, C6, C9, C11, C15, C17, C24, C28, C29,
C33, C35, C39, C123
13
# F5359732R0 0.001UF GRM39B102K50PT CHIP CAPACITOR (1608TYPE) C87, C92, C114, C115, C118, C119 6
# F5359740R0 0.0022UF GRM39B222K50PT CHIP CAPACITOR (1608TYPE) C4, C7, C19 3
# F5350780R0 0.01UF CHIP CAPACITOR (1608TYPE) C57, C58, C59, C60, C61, C122 6
# F5359800R0 0.1UF GRM39F104Z25PT CHIP CAPACITOR (1608TYPE) C3, C13, C16, C20, C22, C26, C37, C38, C40,
C41, C42, C43, C45, C51, C52, C54, C64, C75,
C76, C77, C78, C79, C80, C81, C83, C84, C85,
C88, C89, C91, C93, C94, C95, C96, C97, C98,
C99, C101, C102, C103, C104, C107, C113,
C120, C121
45
# F5359725R0 150P ECJ1VC1H151J CHIP CAPACITOR (1608TYPE) C2, C5, C8, C14, C18, C23 6
# F5359821R0 1U CHIP CAPACITOR (1608TYPE) C67, C36 2
# F5359704R0 22P GRM39CH220J 50PT CHIP CAPACITOR (1608TYPE) C65, C68, C73, C116, C117 5
# F5359805R0 470P J CHIP CAPACITOR (1608TYPE) C90 1
# F5359827R0 68P J CHIP CAPACITOR (1608TYPE) C71, C72, C109, C110 4
# F5369616R0 CSM100M1CC05W 10U/16V CHEMICAL CAPACITOR C21 1
# F5369613R0 CSM101M0JD05W 100U/6.3V
5X5.
CHEMICAL CAPACITOR C53, C63, C74, C82, C86, C100, C105, C106 8
# F5369614R0 CSM101M1CE05W 100U/16V
6.3X5.
CHEMICAL CAPACITOR C44, C46, C70 3
# F5369615R0 CSM470M1CD05W 47U/16V
5X5.3
CHEMICAL CAPACITOR C10, C25, C27, C47, C48 5
INDUCTOR, COIL, FILTER
# F5409148R0 ELL6SH151 SMD COIL L6 1
# F5409147R0 ELL6SH820 SMD COIL L5 1
# F2449239R0 BA-0F601-20057001 INDUCTOR L1, L3, L4 3
# F5409131R0 QT04-60 COIL L2 1
CRYSTAL, RESONATOR
# F5299525R0 HC49SM 16.9344MHZ CRYSTAL X1 1
CONNECTOR
# F3439865R0 B6B-PH-K-S CONNECTOR CN1 1
WIRING, CABLE
# H4009683R0 WIRING 1007 YELLOW 135X3X3 1
# H4009408R0 WIRING 1007 WHITE 85X6X3 1
# H4009498R0 WIRING 1007 PURPLE 160X6EX6E 1
# H4009307R0 WIRING 1007 ORANGE 80X3X6 1
# H4009319R0 WIRING 1007 GREEN 80X3X6 1
# H4009499R0 WIRING 1007 GREEN 160X6EX6E 1
# H4019406R0 WIRING 1007 GRAY 100X3X3 1
# H4009596R0 WIRING 1007 BROWN 110X6X3 1
# H4009597R0 WIRING 1007 BROWN 105X6X3 1

7
Mar. 2006 AC-3
# H4009595R0 WIRING 1007 BLUE 110X6X3 1
# H4009689R0 WIRING 1007 BLACK 105X6X3 1
# G3487434R0 FLAT CABLE 9P L=90MM CN2, CN5 1
WIRING, CABLE
SCREWS
# H5039112R0 WASHER 9X14X0.5 NI 4
# H5029820R0 THUMB SCREW 3X10 FEBC 1
# H5019413R0 SCREW M3X10 BINDING MACHINE FEBC 2
# H5029325R0 SCREW 3X6 B1FEBC 5
# H5039104R0 WASHER 9.2X14X1.6 AL 1
H5039521R0 NUT M7 4
H5039510R0 NUT M9X12X2T NI 4
# H5039401R0 NYLON WASHER M3X6X0.5 2
H5039205R0 TOOTH WASHER 9.1X13 3
# 22137709R0 WASHER 9.6X14X1.0 FOR JACK 1
PACKING
G2627738R0 INNER BOX 1
# G2607509R0 PACKING CASE 1
MISCELLANEOUS
# G2257314R0 INSULATING SHEET PVC T=0.5 + Y525 1
# H5319102R0 INSULOK TIE LCT-80 (3S) YJ-80 WHITE 2
# G2537516R0 PSA CAUTION CE 9V N225 1
# 22537538R0 PSA LABEL 8X13 1
# F3419102R0 BATTERY CONNECTOR 006P BATTERY SNAP 1
# H2369402R0 POLYCA PIPE #306 3X6X6 1
# 22177109R0 COIL SPRING 1
# 22267333R0 CUSHION 1
# 22257257R0 EARTH TERMINAL ET1, ET2 2
# G2167301R0 INSULATING SHEET 1
# 22157702R0 PEDAL GUIDE BUSH 1
ACCESSORIES (Standard)
# G6017460R0 OWNER’S MANUAL JAPANESE 1
# G6027114R0 OWNER’S MANUAL ENGLISH 1
# ******** BATTERY GP1604A 006P 9V 1

8
Mar. 2006 AC-3
Checking Version Number
1. Connect an AC adaptor.
2. Adjust the REVERB, LEVEL, BODY and TOP knobs to MIN.
3. Adjust the MODE knob to STANDARD.
4. While holding down the pedal, connect a plug to the INPUT jack.
5. When the CHECK indicator turns off, release the pedal.
The CHECK indicator blinks and turns off.
6. Then, count the number of times the CHECK indicator blinks.
Examples) Blinks one time: Ver. 1.00
Blinks two times: Ver. 1.01
After showing the version number like this, the test program advances to
the next test item.
Test Mode
Required Items
• Oscillator
• Oscilloscope
• Noise Meter
• 47-kΩshort plug
• Monitor Speaker
Test Items
1. CPU, DSP Check (p. 9)
2. DC Leakage Check (p. 9)
3. REVERB Volume Check (p. 9)
4. LEVEL Volume Check (p. 9)
5. BODY Volume Check (p. 9)
6. TOP Volume Check (p. 10)
7. FET Through, DAC Check (p. 10)
8. Maximum Input/Output Level Check (p. 10)
9. AF/AD Check (p. 11)
10. MODE Switching Check (p. 11)
11. Cross Talk Check (p. 11)
12. Residual Noise Check (p. 12)
13. Noise Check (p. 12)
14. Power and Battery Check (p. 12)
How to Enter Test Mode
Test items are divided into the next three groups, and starting (entering)
method of each test item is different.
Test Mode A: DC Leakage Check (2)–MODE Switching Check (10)
Test Mode B: Cross Talk Check (11)
Test Mode C: Residual Noise Check (12)
Even what test mode you enter, 14. Power and Battery Check (p. 12) is
always executed first.
To execute 13. Noise Check (p. 12) or 14. Power and Battery Check (p. 12),
turn on the power in normal play mode.
The next section explains how to enter each test mode.
Test Mode A
(2. DC Leakage Check–10. MODE Switching Check)
1. Connect an AC adaptor.
2. Adjust all of the REVERB, LEVEL, BODY and TOP knobs to MIN.
3. Adjust the MODE knob to STANDARD.
4. Hold down the pedal and connect an oscillator to the INPUT jack.
5. When the CHECK indicator turns off, release the pedal.
* If there are any knobs which aren’t adjusted to MIN, you won’t be able to enter
the test mode A. And if there are any knobs which minimum values aren’t
detected because of some poor parts, you won’t be able to enter the test mode.
* If you pull out the plug connected to the INPUT jack, the power is turned off.
Then enter test mode again.
* If the CHECK indicator doesn’t turn on, its LED might have some troubles.
Then, confirm the indicator is turned on or off when pressing the pedal in
normal play mode. If the indicator continues to blink, refer to 1. CPU, DSP
Check (p. 9).
Test Mode B (11. Cross Talk Check)
1. Connect an AC adaptor.
2. Adjust all of the REVERB, LEVEL, BODY and TOP knobs to MAX.
3. Adjust the MODE knob to ENHANCE.
4. Hold down the pedal and connect an oscillator to the INPUT jack.
5. When the CHECK indicator turns off, release the pedal.
Test Mode C (12. Residual Noise Check)
1. Connect an AC adaptor.
2. Adjust all of the REVERB, LEVEL, BODY and TOP knobs to MAX.
3. Adjust the MODE knob to PIEZO.
4. Hold down the pedal and connect a 47-kΩshort plug to the INPUT jack.
5. When the CHECK indicator turns off, release the pedal.
How to Exit Test Mode
Press the pedal.
Skip in Test Mode A
After entering Test Mode A, you can select the desired test item, and execute it.
Follow the next procedure.
1. Enter Test Mode A. Refer to Test Mode A (2. DC Leakage Check–10.
MODE Switching Check) (p. 8).
While the CHECK indicator lights, 1. CPU, DSP Check (p. 9) is
executed. If there is no problem, the CHECK indicator blinks and turns
off.
2. Select the desired test item by the MODE knob.
* Tests of 3. REVERB, 4. LEVEL, 5. BODY and 6. TOP Volume Check (when the
MODE knob is adjusted to STANDARD) is always executed in this order.
MODE knob Test Item
STANDARD 3. REVERB, 4. LEVEL, 5. BODY,
6. TOP Volume Check
JUMBO 7. FET Through, DAC Check
ENHANCE 8. Maximum Input/Output Level Check
PIEZO 9. AF/AD Check

9
Mar. 2006 AC-3
Details of Test Items
1. CPU, DSP Check
1. Enter Test Mode A. Refer to Test Mode A (2. DC Leakage Check–10.
MODE Switching Check) (p. 8).
While the CHECK indicator lights, CPU and DSP are tested
automatically.
If there is no problem, the CHECK indicator blinks and turns off.
If the CHECK indicator continues blinking, there might be some troubles of
CPU, DSP or soldering around them. Unplug the AC adaptor to turn off the
power.
2. DC Leakage Check
1. Connect an oscilloscope to both of the LINE OUT jack and the G.AMP
OUT jack.
2. Keep the connection to the INPUT jack, then cut the signal to the INPUT.
If you pull out the plug connected to the INPUT jack, AC-3 exits the test mode
and turns off the power.
3. Confirm the DC level from the LINE OUT and G.AMP OUT are 50 mV or
less.
fig.DCout.eps_30
<< 50 mV/DIV, 1 ms/DIV >>
3. REVERB Volume Check
1. Rotate the REVERB knob clockwise from MIN to center and MAX.
2. Confirm the CHECK indicator turns on, off (at the position of eleven
o’clock), on (one o’clock) and off (MAX).
When the maximum value is detected at the MAX position, the CHECK
indicator turns off and the test is advanced to LEVEL Volume Check.
4. LEVEL Volume Check
* If the maximum value of REVERB volume isn’t detected, the LEVEL Volume
Check won’t be executed.
1. Rotate the LEVEL knob clockwise from MIN to center and MAX.
2. Confirm the CHECK indicator turns on, off (eleven o’clock), on (one
o’clock) and off (MAX).
When the maximum value is detected at the MAX position, the CHECK
indicator turns off and the test is advanced to BODY Volume Check.
5. BODY Volume Check
* If the maximum value of LEVEL volume isn’t detected, the BODY Volume
Check won’t be executed.
1. Rotate the BODY knob clockwise from MIN to center and MAX.
2. Confirm the CHECK indicator turns on, off (eleven o’clock), on (one
o’clock) and off (MAX).
When the maximum value is detected at the MAX position, the CHECK
indicator turns off and the test is advanced to TOP Volume Check.
By the following steps, you can check whether you’ve entered the
test mode successfully or not.
1. Connect an oscilloscope to both of the LINE OUT jack and the
G.AMP OUT jack.
2. Connect an oscillator to the INPUT jack.
3. Input the rectangular wave of 200 Hz, 100 mV p-p to INPUT.
4. Confirm the output waves of LINE OUT and G.AMP OUT are as
follows.
fig.DSPthrough.eps_30
<< 50 mV/DIV, 1 ms/DIV >>

10
Mar. 2006 AC-3
6. TOP Volume Check
* If the maximum value of BODY volume isn’t detected, the TOP Volume Check
won’t be executed.
1. Rotate the TOP knob clockwise from MIN to center and MAX.
2. Confirm the CHECK indicator turns on, off (eleven o’clock), on (one
o’clock) and off (MAX).
7. FET Through, DAC Check
1. Adjust the MODE knob to JUMBO.
The CHECK indicator turns on.
2. Connect an oscilloscope to both of the LINE OUT jack and G.AMP OUT
jack. (Or, confirm they have been connected.)
3. Input the rectangular wave of 200 Hz, 100 mV p-p to INPUT.
4. Confirm the output waves of LINE OUT and G.AMP OUT are as follows.
fig.LINEDAC.eps_30
<< 50 mV/DIV, 1 ms/DIV >>
5. Adjust the REVERB knob to MIN.
The CHECK indicator turns off.
6. Confirm the output waves of LINE OUT and G.AMP OUT are as follows.
fig.GAFET.eps_30
<< 50 mV/DIV, 1 ms/DIV >>
7. Remove the connection of the G.AMP OUT jack.
8. Confirm the output waves of LINE OUT and G.AMP OUT are as follows.
fig.LINEFET.eps_30
<< 50 mV/DIV, 1 ms/DIV >>
9. Remove the connection of the LINE OUT jack, and connect an
oscilloscope to the G.AMP OUT jack.
10. Confirm the output waves of LINE OUT and G.AMP OUT are as follows.
fig.GADAC.eps_30
<< 50 mV/DIV, 1 mS/DIV >>
8. Maximum Input/Output Level Check
1. Adjust the MODE knob to ENHANCE.
The CHECK indicator turns off.
2. Connect an oscilloscope to both of the LINE OUT jack and G.AMP OUT
jack. (Or, confirm they have been connected.)
3. Input the rectangular wave of 200 Hz, +5 dBm [FLAT] to INPUT.
4. Confirm the output waves of LINE OUT and G.AMP OUT are as follows.
fig.maxinout.eps_30
<< 1 V/DIV, 1 ms/DIV >>
5. Connect an noise meter to the LINE OUT jack and the G.AMP OUT jack.
6. Confirm the output level of LINE OUT and G.AMP OUT are +3–+6 dBm
[FLAT].

11
Mar. 2006 AC-3
9. AF/AD Check
1. Adjust the MODE knob to PIEZO.
The CHECK indicator turns on.
2. Connect an oscilloscope to both of the LINE OUT jack and G.AMP OUT
jack. (Or, confirm they have been connected.)
3. Input the rectangular wave of 200 Hz, +5 dBm [FLAT] to INPUT.
4. Confirm the output waves of LINE OUT and G.AMP OUT are as follows.
fig.AFAD.eps_30
<< 50 mV/DIV, 1 ms/DIV >>
10. MODE Switching Check
1. Adjust the REVERB knob to MAX.
2. Adjust the MODE knob to PIEZO, ENHANCE, JUMBO, STANDARD,
JUMBO, ENHANCE and PIEZO in this order, and confirm the CHECK
indicator is as follows.
11. Cross Talk Check
1. Enter Test Mode B. Refer to Test Mode B (11. Cross Talk Check) (p. 8).
While the CHECK indicator lights, CPU and DSP are tested
automatically.
If there is no problem, the CHECK indicator blinks and turns off.
If the CHECK indicator continues blinking, there might be some troubles of
CPU, DSP or soldering around them. Unplug the AC adaptor to turn off the
power.
2. Connect an oscilloscope to both of the LINE OUT jack and G.AMP OUT
jack. (Or, confirm they have been connected.)
3. Input the rectangular wave of 200 Hz, +5 dBm [FLAT] to INPUT.
4. Confirm the output waves of LINE OUT and G.AMP OUT are as follows.
fig.Xtalk1.eps_30
<< 1 V/DIV, 1 ms/DIV >>
5. Remove the connection of the G.AMP OUT jack, and connect an noise
meter to it.
6. Confirm the output level of G.AMP OUT is -90 dBm [JIS-A] or less.
7. Remove the connection of the G.AMP OUT jack, and connect the
oscilloscope again.
8. Adjust the REVERB knob to MIN.
The CHECK indicator turns on.
9. Confirm the output waves of LINE OUT and G.AMP OUT are as follows.
fig.Xtalk2.eps_30
<< 1 V/DIV, 1 ms/DIV >>
10. Remove the connection of the LINE OUT jack, and connect a noise meter
to it.
11. Confirm the output level of LINE OUT is -90 dBm [JIS-A] or less.
MODE knob CHECK indicator
PIEZO turns on
ENHANCE turns off
JUMBO turns on
STANDARD turns off

12
Mar. 2006 AC-3
12. Residual Noise Check
1. Enter Test Mode C. Refer to Test Mode C (12. Residual Noise Check)
(p. 8).
In Test Mode C, you need to connect a 47-kΩshort plug to the INPUT jack, not
a normal plug.
While the CHECK indicator lights, CPU and DSP are tested
automatically.
If there is no problem, the CHECK indicator blinks and turns off.
If the CHECK indicator continues blinking, there might be some troubles of
CPU, DSP or soldering around them. Unplug the AC adaptor to turn off the
power.
2. Adjust the REVERB knob to MIN.
3. Connect a noise meter to the LINE OUT jack and G.AMP OUT jack. (Or,
confirm it has been connected.)
4. Confirm the output level of LINE OUT is -92 dBm [JIS-A] or less and the
output level of G.AMP OUT is also -92 dBm [JIS-A] or less.
13. Noise Check
From here, execute the following tests in normal play mode.
Wait for a while after turning on the power, and then execute this test.
1. Connect a noise meter to the LINE OUT jack and G.AMP OUT jack. (Or,
confirm it has been connected.)
2. Connect a 47-kΩshort plug to the INPUT jack.
3. Adjust all of the REVERB, LEVEL, BODY and TOP knobs to MAX.
4. Adjust the MODE knob to PIEZO.
5. Confirm the output level of LINE OUT is -92 dBm [JIS-A] or less and the
output level of G.AMP OUT is also -92 dBm [JIS-A] or less.
6. Remove the connections of the LINE OUT jack and the G.AMP OUT jack,
then connect a monitor speaker to the LINE OUT jack.
7. Drop the AC-3 twice from the height of about 10 cm to shock its body.
8. Confirm no abnormal noise sounds from the speaker.
9. Remove the plug connected to the LINE OUT jack, and connect the
monitor speaker to the G.AMP OUT jack.
10. Drop the AC-3 twice from the height of about 10 cm to shock its body.
11. Confirm no abnormal noise sounds from the speaker.
12. Confirm no switching noises sounds when the pedal is pressed to switch
on and off.
14. Power and Battery Check
Install a battery and connect an AC adaptor, then start this test.
1. Connect a plug to the INPUT jack. (Or, confirm it has been connected.)
2. Press the pedal, and confirm the CHECK indicator turns on.
3. Remove the AC adaptor’s plug.
4. Press the pedal, and confirm the CHECK indicator turns on.
If the CHECK indicator gets dark, power of battery is consumed.

13
Mar. 2006 AC-3
Circuit Board
fig.PWB.eps

Mar. 2006 AC-3
Circuit Diagram
fig.circuit.eps@L
IN-R
G.AMP OUT
IN-L
OUT-R
OUT-L
AC
ADAPTOR
JACK1 BOARD
(PCB F2927039R0 3/6)
WHT
GLY
YEL
LINE OUT
JACK2 BOARD
(PCB F2927039R0 4/6)
INPUT
BLK
BRN
EXP
YEL
BLU
LEVEL
REVERB
MODE
(PCB F2927039R0 2/6)
TOP
VR BOARD
BODY
LED-GRN
I2C
LED-RED
ESC
(PCB F2927039R0 6/6)
GRN
(PCB 22917496R0)
LED BOARD
RED
LED BOARD
RED
GRN
(RED/GRN)
CHECK
ORG
CHECK
(PCB F2927039R0 5/6)
GRN
SW BOARD
VIO
RESET
WP: H:Protect L:Nomal
EEPROM Writer side:1-2short
5-6 short
BRN
(OUTER)
(INNER)
006P
BLK
RED
AC-3 MAIN BOARD ASSY
75D933P0R0
(PCB F2927039R0 00 1/6)
(uPD8 00402GJ -211-UEN-A)
LINE OUT
MUTE
LINE O UT
THROU GH MUTE
G.AMP OUT
MUTE
G.AMP OUT
THROU GH MUTE
10/10
10/10
10/10
10/10
10/10
10/10
10/10
10/10
10/10
0.47(S)
10/10
(RV-2)
(RV-2)
10/10
10/10
10/10
CN1A
CN1B
CN1C
CN6A
CN6B
CN6C
LRCK
Reset
SDA
MCK
SCL
BCK
LINEOUTMUTE
NIU-INPUT2-SW
LINE-OUT-SW
G-AMP-OUT-SW
LED-RED
NIU-LED-GREEN
NIU-INPUT1-SW
MODE
NIU-EXP2
NIU-EXP1
REVERB
NIU-VR
TOP
BODY
SDOUT
LINETRGHMUTE
GAMPTHRGHMUTE GAMPMUTE
TOP_VR
REVERB_VR
NIU(VR2INNER)
NIU(VR3INNER)
LEVEL
BODY_VR
LEVEL_VR
MODE_VR
SW
SDIN
CODEC PDN
GND_VR
3_3V_VR
+
+
D
+
A
+
D3.3
+
A
+
D
A
A
+
+
D3.3
A
+
A
+
D3.3
+
+
+
+
A
A
+
A
A
A
+
A
+
+
A+
D3.3
A
D
+
D3.3
A
+
D
+
A
+
+
A
+
A
+
+
D
A
+
D
D
+
D3.3
D+1.5
D
+
D3.3
D
+
D3.3
D
+
D3.3
+
D3.3
D
+
D3.3
D
+
D3.3
ESC_3.3V
D+1.5
D
D
D
ESC_1.5V
D D
ESC_3.3V
+
D3.3
D
D
D+1.5
+
D3.3
D
D
ESC_1.5V
ESC_1.5VESC_3.3V
ESC_1.5V
ESC_3.3V ESC_3.3V
ESC_3.3VESC_3.3V ESC_3.3V
ESC_3.3V
ESC_1.5V
ESC_1.5V
ESC_3.3V
ESC_3.3V
ESC_3.3V
ESC_3.3V
ESC_1.5V
ESC_1.5V
ESC_3.3V ESC_3.3V
ESC_3.3V
ESC_1.5V
ESC_1.5V
+
D3.3
D
D
+
D3.3 + D3.3
D
D
+
D3.3
A
+
D3.3 + D3.3
D
D
+
D3.3
+
D3.3
D D
+
D3.3 + D3.3
+
D3.3 + D3.3
D D
+
D3.3 + D3.3
D D
+
D3.3
A
+
+
D3.3
+
A
A
D
+
D3.3
+
D3.3
D
D
+
D3.3
D
AD3R3V
AD3R3V
D
A
A
D
+
DA
D
D
D
D D
D
+
D3.3
D
D DD
DD D
D
D
DD
DD
D D
D DD
D
+
D3.3
C32
NIU(S)
C43
0.1
C40
0.1
R28 47k
R27
4.7k
C4
0.0022
C12
ECPU1E474KB5
R5
4.7k
C31
NIU
R50
56k R56 1M
R6 47 k
+
-
IC4C
M5218AFP
84
R24
4.7k
R34
100k
Q5
2SK879Y
3
12
R36
15k
R9
4.7k
R13
1M
R54
1M
+
-
IC2C
NJM2100M
84
R55
100k
C26
0.1
R3
22k
+
-
IC3B
M5218AFP
6
5
7
+
-
IC2A
NJM2100M
2
3
1
C21
10/16
R49
1M
+
-
IC4B
M5218AFP
6
5
7
C23 150p
R19
10k
R42
NIU
R17
56k
R61
56k
+
-
IC2B
NJM2100M
6
5
7
C22
0.1
R4
47k
R8 56 k
R40
NIU
R57
1M
C25
47/16
C38
0.1
+
-
IC1A
M5218AFP
2
3
1
+
-
IC4A
M5218AFP
2
3
1
R31
1k
Q3
2SK880GR
3
1 2
C2
150p
R62
56k
R51
100k
R53
100k
R29
10k(MF)
R18
1M
R23
10
Q6
NIU(2SK880GR)
3
1 2
R16
15k
+
-
IC3A
M5218AFP
2
3
1
+
-
IC1B
M5218AFP
6
5
7
C5 15 0p
R14
100k
R41
NIU
R21
4.7k
C30
NIU
R64
56k
R46
56k
R35 47k
R44
56k
C10
47/16
R33
1M
C19
0.0022
R2
4.7k
R38
NIU R39 150k(MF)
R45
56k R52
100k
R37
NIU
C27
47/16
Q4
2SK879Y
3
12
C18
150p
C42
0.1
C37
0.1
C8
150p
R32 56k
C41
0.1
+
-
IC1C
M5218AFP
84
D4
1SS387
12
D1
1SS387
12
D3
1SS387
12
Q2
2SK879Y
3
12
D2
1SS387
12
Q1
2SK879Y
3
12
Q7
2SC4738
1
2 3
Q8
2SC4738
1
2 3
Q10
2SC4738
1
2 3
Q9
2SC4738
1
2 3
R75
2.2k
C45
0.1
C44
100/16
L2
QT04-60
1
2
4
3
C49
NIU
JK5
NIU
9
4
8
7
6
3
2
JK3
NIU
9
4
8
7
6
3
2
23
1
24
1
25
1
13
1
14
1
15
1
JK1
HTJ-064-14D
1
2
3
Q13
2SA1832
1
32
R73
1k
R78
NIU
1
R11
1k
JK4
HTJ-064-12DS
1
2
3
R15
10k
JK2
HTJ-064-13D
1
2
3
JK6
HEC2392-01-150
2
1
3
4
5
Q11
2SC4738
1
23
R121
10k(MF)
C90
470p
R114 10k(MF)
R109
47k
C72
68p
R112
22k(MF)
R107
47k(MF)
R103
3.3k(MF)
C88
0.1 R120
56
R110
56
Q15
QS5U27
1
5 2
34
C89
0.1
Q16
QS5U27
1
5 2
34
C107
0.1
C75
0.1
C91
0.1
R122
27k(MF) C93
0.1
R117
15k(MF)
R119
10k(MF)
R115
10k(MF)
R106
47k
C71
68p
R113
47k(MF)
R108
18k(MF)
R111
47k
C87
0.001 R118
47k
C92
0.001
C70
100/16
JK7
NIU(HTJ-064-14D)
1
2
3
R116 27k(MF)
IC9
BD9851EFV
SEL1
1
RT
2
CT
3
NON2
4
INV2
5FB2
6
DTC2
7
PVCC2 8
OUT2 9
PGND 10
OUT1 11
PVCC1 12
DTC1
13
SCP
14
FB1
15
INV1
16
VREF
17
VCC 18
STB
19
GND
20
L5
ELL6SH820
L6
ELL6SH151
R76
56k
TP47
1
R83
NIU
L3
FBMA1608-601
C65
22P
R94 0
R105 39
R80
22k
Q14
NIU(2SA1832)
1
32
L4
FBMA1608-601
C68
22P
R88
10k
R92
0
TP16 1
IC6
HN58X24512I
A0 1
A1 2
NC 3
VSS
4SDA 5
SCL 6
WP 7
VCC
8
TP14 1
X1
16.9344MHz
1 2
C101
0.1
LED2
NIU
1 2
3
LED1
L-34HDSL
1 2
1
1
1
Q12
2SC4738
1
23
SW1
JM-0404
1 2
R81
NIU
R84
NIU
R82
NIU
R85
NIU C50 NIU
10
1
TP13
1
R96
1k
R95
100k
11
1
12
1
R47
10k(MF)
R22
0
3
1
R65
NIU R66 NIU
R70
NIU
R71
NIU
TP56
1
TP57
1
TP58
1
TP59
1
TP60
1
C73
22p
R67
NIU
C66
NIU
R43
22k
R58
1k R59
22k
R69
1k
DA7
NIU(1SS362)
2 1
3
DA8
NIU(1SS362)
2 1
3
DA3
NIU(1SS362)
2 1
3
DA4
NIU(1SS362)
2 1
3
DA5
NIU(1SS362)
2 1
3
DA6
NIU(1SS362)
2 1
3
R101
NIU
C79
0.1
C52
0.1
TP49
1
CN1
B6B-PH-K-S
1
1
2
2
3
3
4
4
5
5
6
6
DA2
NIU(1SS362)
21
3
DA1
NIU(1SS362)
21
3
R102
10k
R26
100
C99
0.1
C81
0.1
R98
10k
R99
10k
C14
150p
C16
0.1
R74
10k(MF)
C13
0.1
L1
FBMA1608-601
+
-
IC3C
M5218AFP
84
C20
0.1
C3
0.1
R100
10k
TP48
1
TP50
1
TP51
1
TP52
1
TP53
1
TP54
1
TP55
1
C67
1u
TP46
1
TP45
1
TP44
1
TP43
1
TP42
1
TP41
1
TP40
1
C100
100/6.3
TP30
1
TP31
1
TP32
1
TP33
1
TP34
1
TP35
1
TP36
1
TP37
1
IC7
ESC
XOUT
140
XIN
139
TXD1/P61
70
TXD0/P76
74
TMODE1
98
TMODE0
99
TMC2
136 TMC1
135
TI/P74
76
TCLR/BUDO0/P73
77
TRST
137
SMC
142
SDA
80
SD7/TRR7/P87
112
SD6/TRR6/P86
113
SCL
79
SYNC/SD3/TRR3/P83
118
RXD0/P75
75
RESET
81
PWM/SD2/TRR2/P82
119
MCK/TRCKI/P71
110
LRCK/SYNC/P72
107
IVDD 41 IVDD 101 IVDD 108 IVDD 55 IVDD 36 IVDD 72 IVDD 141
EVDD 9 EVDD 17 EVDD 26 EVDD 34 EVDD 49 EVDD 61 EVDD 82 EVDD 96 EVDD 114 EVDD 122 EVDD 132 EVDD 144
BCK/TRCKO/P70
111
AVREFP
85
AVREFM
94
AVDD2
84
AVDD1
134
AMC
143
AIN7
93
AIN6
92
AIN5
91
AIN4
90
AIN3
89
AIN2
88
AIN1
87
AIN0
86
AGND2
95
AGND1
133
CS4/SD0/TRR0/P80 121
A23/SYNC/TRS7/P97 124
A22/TRS6/P96 125
A21/TRS5/P95
A20/TRS4/P94
A19/TRS3/P93
A18/TRS2/P92
A17/TRS1/P91 130
EGND
1
EGND
10
EGND
18
EGND
27
EGND
35
EGND
50
EGND
62
EGND
83
EGND
97
EGND
115
EGND
123
IGND
37
IGND
42
IGND
73
IGND
100
IGND
109
IGND
138
EA7/AD15/P37 29
EA6/AD13/P35 31
EA5/AD11/P33 33
EA4/AD9/P31 39
EA3/AD8/P30 40
EA2/AD10/P32 38
EA1/AD12/P34 32
EA0/AD14/P36 30
INT2/SD1/TRR1/P81 120
R63
56k
TP15
1
TP21
1
TP23
1
TP25
1
2
1
1
1
8
1
9
1
16
1
19
1
20
1
21
1
22
1
17
1
18
1
4
1
1
1
6
1
26
1
27
1
5
1
7
1
VR1A
RD912D-B54-6009
11
12
13
VR4
RD901-B54_04
1
2
3
C78
0.1
C95
0.1
C96
0.1
C77
0.1
BT1
GP1604A
12
28
1
29
1
C112
NIU
R7
22k
C7
0.0022 R12
15k
TP94
1
TP91
1
TP97
1
TP100
1
TP98
1
TP84
1
TP85
1
TP86
1
TP87
1
TP88
1
TP102
1
TP95
1
TP103
1
C109
68p
C110
68p
C108 NIU
C111NIU
C83
0.1
C80
0.1
C98
0.1
VR1B
RD912D-B54-6009
21
22
23
C86
100/6.3
C102
0.1
C82
100/6.3
VR2A
RD901-B54-006
11
12
13
VR2B
RD901-B54-006
21
22
23
VR3B
RD901-B54-006
21
22
23
VR3A
RD901-B54-006
11
12
13
CN5
9pinRibbonCN
1
1
2
2
3
3
4
4
5
5
6
6
7
7
8
8
9
9
CN2
9pinRibbonCN
11
22
33
44
55
66
77
88
99
30
1
R25
22k
TP82
1
R104
5.6k(MF)
IC10A
TC7W04FK
1 7
IC10B
TC7W04FK
3 5
C34
NIU(GRM31MF51A106)
C15
GRM3 1MF51A106
C11
GRM31MF51A106
C29
GRM3 1MF51A106
C1
GRM31MF51A106
C9
GRM31MF51A106
C17
GRM31MF51A106
C24
GRM31MF51A106
R130 NIU
R131 NIU
R132 0
R133 0
R134 0
R135 0
R136 0
R137 NIU
R126
10k
R127
10k
R129
10k
R128
10k
R138 100
R139 100
R140 100
C115
0.001 C114 0.001
R20
1M
R1
1M
C117
22p
C116
22p
AK4552VT
IC5
RIN
1
LIN
2
VSS
3
VA 4
VD 5
DEMO
6DEM1
7
SDTO 8 SDTI
9
LRCK
10
MCLK
11
BCLK
12
PDN
13
VCOM 14
LOUT 15
ROUT 16
R48 100
C33
GRM31MF51A106
C35
GRM31MF51A106
R142
3.9k
R141
NIU
C120
0.1
C118
0.001
C119
0.001
D5
SS14
R143
4.7k
C122
0.01
C36
1u
R87
10k
R91
10k
IC10C
TC7W04FK
6 2
Q17
2SC4738
1
2 3
ET1
EARTH_TERMINAL
ET2
EARTH_TERMINAL
R144
22k
1
1
1
C48
47/16
C57
0.01
R77
12k(MF)
C62
NIU
C55
NIU
C56
NIU
C121
0.1
C64
0.1
D6
GS1G
R60
10k(MF)
C47
47/16
C39
GRM31MF51A106
C60
0.01
C51
0.1
C106
100/6.3
C61
0.01
C58
0.01
C74
100/6.3
C53
100/6.3
C63
100/6.3
C46
100/16
C54
0.1
C59
0.01
C76
0.1
C105
100/6.3
C84
0.1
C103
0.1
C104
0.1
IC10D
TC7W04FK
84
C94
0.1
C113
0.1
R79
39k
C97
0.1
C85
0.1
C123
GRM3 1MF51A106
C6
GRM3 1MF51A106
C28
GRM3 1MF51A106
IC8
BD45301G
VDD 5
SUB
2
GND
3
ER
1
VOUT 4
R123
56k
9pin RIBBON CABLE
BLU
1514

MEMO
AC-3