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SERVICE NOTESIssued by RJA
Copyright 2002 ROLAND CORPORATIONAll rights reserved. No part of this publication may be reproduced in any form without the written permissionof ROLAND CORPORATION.
Printed in Japan (0800) (NB)17058015E0
Apr.2002 OD-20(T)
TABLE OF CONTENTS
SPECIFIC.ATIONS............................................................2
LOCATION OF CONTROLS ..........................................4LOCATION OF CONTROLS PARTS LIST ...................5EXPLODED VIEW ............................................................6EXPLODED VIEW PARTS LIST .....................................9PARTS LIST......................................................................10CHECKING THE VERSION NUMBER.......................13
RESTORING THE FACTORY SETTINGS...................13TEST MODE.....................................................................13BLOCK DIAGRAM.........................................................16CIRCUIT BOARD(JACK)...............................................18CIRCUIT BOARD(PANEL) ...........................................19CIRCUIT DIAGRAM(JACK) .........................................20CIRCUIT DIAGRAM(PANEL)......................................22
(T)
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SPECIFIC.ATIONS
OD-20: Overdrive/Distortion
Nominal Input Level
-20 dBu
Input Impedance
1 M
Nominal Output Level
-20 dBu
Output Impedance
1 k
Recommended Load Impedance
10 k or greater
Dynamic Range
102 dB (IHF-A typ.)
Controls
EFFECT ON/OFF Pedal
MANUAL/MEMORY Pedal
DRIVE Knob
BOTTOM Knob
TONE Knob
LEVEL Knob
ATTACK SHAPE Knob
HEAVY OCTAVE Knob
TYPE Knob
VARIATION Button
AMP CTRL (amp control) Button
MEMORY WRITE Button
MEMORY SELECT Button
Indicators
POWER Indicator (serves also as battery check indicator)
EFFECT ON/OFF Indicator
MANUAL Indicator
MEMORY Indicator
VARIATION Indicator
AMP CTRL (amp control) Indicator
MEMORY Number Indicator (1-4)
Connectors
INPUT Jack
AMP CTRL (amp control) Jack
LINE OUT/PHONES Jack
OUTPUT Jack
AC Adaptor Jack (DC 9 V)
Power Supply
DC 9 V: Dry Battery (R6/LR6 (AA) type) x 6
AC Adaptor
Current Draw
85 mA (9 V max.)
* Expected battery life under continuous use:
Carbon: 8 hours
Alkaline: 20 hours
These figures will vary depending on the actual conditions of use.
Dimensions
173 (W) x 158 (D) x 57 (H) mm
6-13/16 (W) x 6-1/4 (D) x 2-1/4 (H) inches
Weight
1.1 kg / 2 lbs 7 oz (including batteries)
Accessories
Owners Manual
English :G6017351
Japanese :G6017350
Leaflet (USING THE UNIT SAFELY, IMPORTANT NOTES, and
Information):(********)
Dry battery (LR6 (AA) type) x 6:(********)
* We recommend that alkaline batteries be used when replacing the batteries.
Options
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.
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LOCATION OF CONTROLSfig.front
fig.rear
1
2
3
6
7 910
5
8
11
12
13
14
15
1617
4
23
64 57
1 8
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OD-20(T)
LOCATION OF CONTROLS PARTS LIST
[Front]
[Rear]
No. PART CODE PART NAME DESCRIPTION QTY
1 H5029855 SCREW M4X8 HEXAGON BUTTON HEAD 4
2 G2477122 R-KNOB 5
F3279802 POTENTIOMETERNO CLICK 50KB RD901-40-125F-B54-00D 5
3 G247751001 VGA KEYTOP S BLACK WITH LENS 2
4 G2477122 R-KNOB 1F3279803 POTENTIOMETER 11 CLICKS 50KB RD901-40-125F-B54-11D 1
5 H5029851 PEDAL SHAFT 1
6 1502928100 LED (RED) L-34HDSL 3
7 G2187540 PEDAL L 1
8 G2017180 CASE 1
9 G2217171 LED PANEL 1
10 G2187541 PEDAL R 1
11 H5029852 SCREW 4M3 FEBZC HEXAGON SOCKET BUTTON HEAD 2
12 G2357116 PEDAL PLATE 62X53 2
13 F5029126 POWER LED L-113GDT 1
14 G247751301 VGA KEYTOP S WITHOUT LENS 2
15 1502928100 LED (RED) L-34HDSL 4
16 G2217170 PANEL 1
17 G2477122 R-KNOB 1
F3279819 POTENTIOMETER CENTER CLICK 50KB RD901-40-125F-B54-0CD 1
No. PART CODE PART NAME DESCRIPTION QTY
1 13449150MF PHONE JACK (STEREO) HTJ-064-12D 3
2 G2537552 LABEL CAUTION 1
3 G2217172 REAR PANEL 1
4 G2017621 BATTERY COVER 1
5 G2017148 BOTTOM COVER 1
6 G2357118 BOTTOM FOOT 1
7 F3449415 ADAPTOR JACK KM02009AB 1
8 13449155MF PHONE JACK (MONO) HTJ-064-12I 1
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EXPLODED VIEWfig.expro1
33
32
26
24
c
k
21
b
d
23
25
b
e
f
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fig.expro2
a
11
18
a
12
18
11
16
j
14
15
17
10
13
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fig.expro3
1
2
5
3i
4
g
hRIGHT SIDE
LEFT SIDE9
6
7
8
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EXPLODED VIEW PARTS LIST
[Part]
[Screw]
No. PART CODE PART NAME DESCRIPTION QTY
1 G2017180 CASE 1
2 G2357111 CUSHION R 2
3 H5029851 PEDAL SHAFT 2
4 2215770201 PEDAL GUIDE BUSH 215-702 2
5 2217710900 COIL SPRING 214-109 2
6 G2357116 PEDAL PLATE 62X53 27 G2357115 PEDAL FOOT M8 2
8 G2187541 PEDAL R 1
9 G2187540 PEDAL L 1
10 G2017148 BOTTOM COVER 1
11 G2357118 BOTTOM FOOT 2
12 G2017621 BATTERY COVER 1
13 G2017620 BATTERY CASE 1
14 G2177308 BATTERY TERMINAL(+) 1
15 G2177309 BATTERY TERMINAL(-) 1
16 G2177307 BATTERY TERMINAL(+-) 1
17 G2257130 BATTERY INSULATING SHEET 1
18 G2537552 LABEL CAUTION QUICK MANUAL 1
21 G2477122 R-KNOB 7
23 G2257129 INSULATING SHEET 1
24 G2217170 PANEL 1
25 G2217172 REAR PANEL 1
26 G2217171 LED PANEL 1
32 G247751301 VGA KEYTOP S WITHOUT LENS 2
33 G247751001 VGA KEYTOP S BLACK WITH LENS 2
No. PART CODE PART NAME DESCRIPTION QTY
a H5029115 SCREW 3X8 PAN TAPTITE-2 FEBZC 7
b H5019110 SCREW M3X6 PAN TAPTITE-2 FEZC 9
c H5029855 SCREW M4X8 HEXAGON SOCKET BUTTON HEAD FENI 4
d H5039205 WASHER 12.5X9.5X0.5/0.9 INTERNAL TOOTH FENI 4
e H5039112 WASHER M9 4
f H5039510 NUT M9X12X2 FENI 4
g H5029852 SCREW 4M3 FEBZC HEXAGON SOCKET BUTTON HEAD 2
h H5039413 NYLON WASHER M4.1X7.5X0.5 BLACK 2i H5039414 NYLON WASHER M5.1X9.5X0.5 BLACK 2
j H5019430 SCREW M2.6X5 BINDING HEAD TAPTITE FEZC 2
k H5039521 VR ACCESSORY NUT M7 7
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PARTS LISTfig.part1e
SAFETY PRECAUTIONS:The parts marked havesafety-related characteristics. Useonly listed parts for replacement.
CONSIDERATION ON PARTS ORDRINGWhen ordering any parts listed in the parts list, please specify the following items in the order sheet.
QTY PART NUMBER DESCRIPTION MODEL NUMBEREx. 10 22575241 Sharp Key C-20/50
15 2247017300 Knob (orange) DAC-15DFailure to completely fill the above items with correct number and description will result in delayed or even
undelivered replacement.
NOTE: The parts marked # are new. (initial parts)
CASING
G2357116 PEDAL PLATE 62X53 2
G2017620 BATTERY CASE 1
G2017621 BATTERY COVER 1
G2017148 BOTTOM COVER 1
G2357118 BOTTOM FOOT 2
# G2017180 CASE 1
# G2217171 LED PANEL 1
# G2217170 PANEL 1
# G2187541 PEDAL R 1
# G2187540 PEDAL L 1
H5029851 PEDAL SHAFT 2
# G2217172 REAR PANEL 1
KNOB,BUTTON
G2477122 R-KNOB 7
G247751001 VGA KEYTOP S BLACK WITH LENS 2
G247751301 VGA KEYTOP S WITHOUT LENS 2
SWITCH
01780101 SKQKAB TACT SWITCH SW3, SW4, SW5, SW6 on PB 4
13129778 SKQKAH TACT SWITCH SW1, SW2 on PB 2
JACK,EXT TERMINAL
13449150MF HTJ-064-12D PHONE JACK (STEREO) JK1, JK2, JK3 on JB 3
13449155MF HTJ-064-12I PHONE JACK (MONO) JK4 on JB 1
F3449415 KM02009AB ADAPTOR JACK JK5 on JB 1
PWB ASSY
# E 75D693P000 JACK PWB ASSY
# 75D693M000 PANEL PWB ASSY
IC
# 02897545 MN101C30AHD OD-20 VER1.00 IC(CPU 8BIT) IC6 on JB 1
# F5209123 S-80930ALMP-DAT-T2 IC (REST) IC7 on JB 1
F5179604 CAT24WC02J IC (EEPROM) IC4 on JB 1
02565501 TC220CCA0AF-B01(MR3) IC (DSP) IC5 on JB 1
# F5179125 S-8520E33MC-BJS-T2 IC (DC-DC) IC8 on JB 1
15289109 M5216FP-600D IC (BIPOLAR OP AMP) IC10, IC11 on JB 2
15189261 M5218AFP-600E IC (BIPOLAR OP AMP) IC3 on JB 1
00346445 NJM2100M(TE3) IC (BIPOLAR OP AMP) IC1 on JB 1
02451434 AK4552VT IC (AD/DA) IC2 on JB 1
TRANSISTOR
00679045 2SA1298-Y(TE85R) TRANSISTOR Q5 on JB 1
15309104 2SA1586-GR(TE85R) TRANSISTOR Q4 on JB 1
15319108 2SC-3324GR-TE85R TRANSISTOR Q3, Q12 on JB 2
00562012 2SC3265-Y(TE85R) TRANSISTOR Q7 on JB 1
15319107 2SC4116-GR(TE85R) TRANSISTOR Q6, Q9, Q10 on JB 3
F5139608 IRF7606 POWER MOS FET Q11 on JB 1
# F5329530 2SK879Y FET TRANSISTOR Q2, Q8 on JB 2
15329103 2SK880GR-TE85R FET TRANSISTOR Q1 on JB 1
DIODE
02562878 02DZ5.1-Y(TPH3) ZENER DIODE D8 on JB 1
01019534 1SS355 TE-17 SWITCHING DIODE D1, D4, D6, D10 on JB 4
F5029126 L-113GDT POWER LED LED2 on PB 1
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1502928100 L-34HDSL LED (RED) LED3, 4, 5, 8, 9, 10, 11 on PB 7
F5029117 L-312LRD LED LED6, 7 on PB 2
15339119 1SS-352 DIODE D2 on JB 1
00783034 1SS294(TE85L) DIODE D3 on JB 1
15339120 1SS302 DIODE DA3 on JB 1
F5339137 SS14 VF=0.45V DIODE D5, D7 on JB 2
DIODE
RESISTOR
F5419707 CRN34101J RESISTOR ARRAY RA5,6 on JB 2
# F5399951 68(1/2W) CHIP RESISTOR (1/2W) R64, R68 on JB 2# F2569127 MINISMDC075 POLY SWITCH R48 on JB 1
00566867 RPC05T 100 J MTL.FILM RESISTOR R37, R76, R77, R79 on JB 4
00567023 RPC05T 101 J MTL.FILM RESISTOR R51 on JB 1
00567156 RPC05T 102 J MTL.FILM RESISTOR R6, R61 on JB 2
00567289 RPC05T 103 J MTL.FILM RESISTOR R1, R7, R11, R12, R13, R14, R15, R17, R19, 25
00567412 RPC05T 104 J MTL.FILM RESISTOR R10, R28, R45, R67, R75, R78, R82, R83, R86 12
00567556 RPC05T 105 J MTL.FILM RESISTOR R2, R3, R5, R27, R29, R44, R60 on JB 7
00567290 RPC05T 123 J MTL.FILM RESISTOR R25, R34 on JB 12
00567301 RPC05T 153 J MTL.FILM RESISTOR R23, R36 on JB 2
00567190 RPC05T 222 J MTL.FILM RESISTOR R57 on JB 1
00567334 RPC05T 273 J MTL.FILM RESISTOR R59 on JB 1
00566934 RPC05T 330 J MTL.FILM RESISTOR R54 on JB 1
00567089 RPC05T 331 J MTL.FILM RESISTOR R62, R69, R82 on JB 3
00567367 RPC05T 393 J MTL.FILM RESISTOR R30 on JB 1
00567245 RPC05T 472 J MTL.FILM RESISTOR R9, R66, R88 on JB 3
00567378 RPC05T 473 J MTL.FILM RESISTOR R8, R16, R21, R26, R31, R41, R47, R52, R53, 1100567501 RPC05T 474 J MTL.FILM RESISTOR R4, R74 on JB 2
00567134 RPC05T 681 J MTL.FILM RESISTOR R72 on JB 1
# F3829270 27(2W) METAL OXIDE RESISTOR R18, 22 on JB 2
F5429365 10K OHM F RANK (1%) CHIP RESISTOR R24 on JB 1
F5429386 150K F (1608TYPE) CHIP RESISTOR R20 on JB 1
# F5419740 CRN34473J CHIP ARRAY RESISTOR RA4 on JB 1
# F5419741 CRN34681J CHIP ARRAY RESISTOR RA2,3 on JB 2
POTENTIOMETER
# F3279819 RD901-40-125F-B54-0CD 50KB ROTARY POT. W/CENTER CLICK VR2 on PB 1
F3279802 RD901-40-125F-B54-00D POTENTIOMETERNO CLICK 50KB VR1, VR3, VR4, VR5, VR6 on PB 5
F3279803 RD901-40-125F-B54-11D POTENTIOMETER 11 CLICKS 50KB VR7 on PB 1
CAPACITOR
02341489 ECPU1C474MA5 MYLAR CAPACITOR(SUBMI-CRON)
1
# F5349704 ECPU1C474MA5 MYLAR CAPACITOR (SUBMI-CRON)
C1 on JB 1
# F5359732 GRM39B102J50PT CHIP CAPACITOR (1608 TYPE) C80 on JB 1
F5359780 GRM39B103K50PT CHIP CAPACITOR (1608 TYPE) C55, C56, C57, C58, C59, C60, C61, C72 on J 8
# F5359382 GRM39B182J50PT CHIP CAPACITOR (1608 TYPE) C89, C95 on JB 2
F5359740 GRM39B222K50PT CHIP CAPACITOR (1608 TYPE) C5, C9 on JB 2
# F5359812 GRM39B473J50PT CHIP CAPACITOR (1608 TYPE) C17, C33 on JB 2
# F5359372 GRM39B683J50PT CHIP CAPACITOR (1608 TYPE) C67 on JB 1
F5359720 GRM39CH101J50PT CHIP CAPACITOR (1608 TYPE) C6 on JB 1
# F5359803 GRM39CH151J50PT CHIP CAPACITOR (1608 TYPE) C83, C85, C88, C90 on JB 4
# F5359370 GRM39CH180J50PT CHIP CAPACITOR (1608 TYPE) C69 on JB 1
F5359704 GRM39CH220J50PT CHIP CAPACITOR (1608 TYPE) C68, C70, C71 on JB 3
# F5359373 GRM39CH271J50PT CHIP CAPACITOR (1608 TYPE) C12, C13, C22 on JB 3
F5359800 GRM39F104Z25PT CHIP CAPACITOR (1608 TYPE) C11, C21, C24, C26, C30, C32, C35, C36, C37 30
# F3629692 0.22/50V CAPACITOR C87 on JB 1# F3629695TS 1/50V CAPACITOR C2, C3, C19, C29, C91, C94 on JB 6
# F3629678TS 10/16V CAPACITOR C4, C7, C8, C10, C14, C15, C16, C18, C20, C 14
# 13629550KM 100/16V CAPACITOR C31, C49, C52, C54, C76, C78, C81, C86, C92 9
# 13629509KM 47/16V CAPACITOR C34, C74 on JB 2
INDUCTOR,COIL,FILTER
F2449216 SLF7045T-151MR40 SMD COIL L3 on JB 1
02563478 NFM4516P13C204F EMI FILTER C48 on JB 1
F2449210 SLF7032T-4R7M1R7-2(4.7UH) COIL L2 on JB 1
CRYSTAL,RESONATOR
02673278 CX-49G 11.2896MHZ CRYSTAL X2 on JB 1
F5299108 HC-49SM 8MHZ CRYSTAL X1 on JB 1
CONNECTOR
F3439160 53015-0210 2P P=2MM CONNECTOR CN4 on JB 1
F3439165 A2001WR2-10P CONNECTOR CN1 on JB 1
# F3439200 A2001WR2-15P CONNECTOR CN2 on JB 1
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WIRING,CABLE
G3487163 WIRING BATTERY L=80MM 2P 1
# G3467251 WIRING 15P L=52MM P=2MM CN2 on PB 1
# G3487421 WIRING 10P L=40MM P=2MM CN1 on PB 1
G3477146 RIBBON CABLE 3P L=40X5X5 MM P=2MM CN3 on JB 1
SCREWS
H5019110 SCREW M3X6 PAN TAPPING-2 FEZC 10
H5029115 SCREW 3X8 PAN TAPPING-2 FEBZC 7H5039205 WASHER 12.5X9.5X0.5/0.9 INTERNAL TOOTH FENI 4
H5029852 SCREW 4M3 FEBZC HEXAGON SOCKET BUTTON HEAD 2
# H5029855 SCREW M4X8 HEXAGON BUTTON HEAD 4
H5039510 NUT M9X12X2 FENI 4
H5039413 NYLON WASHER M4.1X7.5X0.5 BLACK 2
H5039414 NYLON WASHER M5.1X9.5X0.5 BLACK 2
H5019430 SCREW M2.6X5 BINDING HEAD TAPTITE FEZC 2
H5039521 VR ACCESSORY NUT M7 7
H5039112 WASHER M9 4
PACKING
# G2627250 PACKING CASE 1
G2607212 PACKING CASE LOWER 1
G2237614 REAR PAD 1
G2237613 SIDE PAD 1
MISCELLANEOUS
G2357115 PEDAL FOOT M8 2
H2369427 LED SPACER H=8MM 4
2215770201 PEDAL GUIDE BUSH 215-702 2
2217710900 COIL SPRING 214-109 2
G2257130 BATTERY INSULATING SHEET 1
G2177308 BATTERY TERMINAL(+) 1
G2177307 BATTERY TERMINAL(+-) 1
G2177309 BATTERY TERMINAL(-) 1
G2357111 CUSHION R 2
G2257129 INSULATING SHEET CENTER 1
# G2537552 LABEL CAUTION 1
G2197126 LED GUIDE 1
ACCESSORIES (Standard)
# G6017350 OWNERS MANUAL JAPANESE 1
# ******** ALKALINE BATTERY LR6SG-P2 3
# G6017351 OWNERS MANUAL ENGLISH 1
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OD-20(T)
CHECKING THE VERSIONNUMBER
After you enter test mode, perform step 5.
1. Turn all knobs to MIN (all the way to the left).
2. While holding down the left pedal and the right pedal, insert the 9V plug
into DC IN.
At this time, only the POWER LED will light.
3. Release the left and right pedals. The EFFECT ON/OFF LED will blink.
4. Within four seconds, press the left pedal and then the right pedal.
If you were successful in entering test mode, the EFFECT ON/OFF LED,
MANUAL LED, and MEMORY LED will light.
5. Set the TYPE volume to METAL/LOUD.
. The version number will be indicated as follows.
For Ver1.00, only the MEMORY 2 LED will light.
(The integer portion is indicated by the MEMORY 1 and 2 LEDs
1: MEMORY 1 LED: dark MEMORY 2 LED: lit
2: MEMORY 1 LED: lit MEMORY 2 LED: dark
3: MEMORY 1 LED: lit MEMORY 2 LED: lit
The first decimal place is indicated by the MEMORY 3 and 4 LEDs
0: MEMORY 3 LED: dark MEMORY 4 LED: dark1: MEMORY 3 LED: dark MEMORY 4 LED: lit
2: MEMORY 3 LED: lit MEMORY 4 LED: dark
3: MEMORY 3 LED: lit MEMORY 4 LED: lit
The second decimal place is indicated by the MANUAL LED and
MEMORY LED
0: MANUAL LED: dark MEMORY LED: dark
1: MANUAL LED: dark MEMORY LED: lit
2: MANUAL LED: lit MEMORY LED: dark
3: MANUAL LED: lit MEMORY LED: lit )
RESTORING THE FACTORY
SETTINGSReturning Settings to Their Factory Defaults
You can restore the memories (1-4), pedal mode settings, and the MEMORY
Number Indication to their original factory values.
Memory Settings
Memory 1 LOUD
Memory 2 LEAD
Memory 3 OD-1
Memory 4 STACK
Pedal Mode
1 (MANUAL -> MEMORY 1 -> MEMORY 2 -> MEMORY 3 -> MEMORY 4 ->
MANUAL)
MEMORY Number Indication
Lighting Pattern 1(Only the indicator for the selected memory lights up.)
Carrying out the following procedure completely clears the content currently
stored in the memories (1-4).
1. Switch off the power.
Disconnect the connection plug from the INPUT jack.
2. While holding down the WRITE button, switch on the power.
Insert the connection plug into the INPUT jack.
When you release the button, the MEMORY Number indicators blink.
3. Press the MEMORY WRITE button.
After the MEMORY Number indicators begin blinking rapidly, the
setting is stored in memory and the unit returns to its ordinary state.
* To cancel the setting change, operate the EFFECT ON/OFF pedal or the
MANUAL/MEMORY pedal before pressing the MEMORY WRITE button.The unit will return to its ordinary state.
TEST MODE
Required items1. Oscillator
2. Noise meter
3. Oscilloscope
4. Monitor amp (e.g., MA-12)
5. Guitar amp (with a channel-switching jack)
6. Stereo plug
7. 47k short plug
1. How to enter test mode1. Turn all knobs to MIN (all the way to the left).
Connect a short plug (47k) to INPUT.
2. While holding down the left pedal and right pedal, insert the 9V plug into
DC IN.
At this time, only the POWER LED will light.
3. Release the left and right pedals. The EFFECT ON/OFF LED will blink.
4. Within four seconds, press the left pedal and then the right pedal.
If you were successful in entering test mode, the EFFECT ON/OFF LED,
MANUAL LED, and MEMORY LED will light.
2. List of test items
1. IC check
2. Switching noise / shock noise check
3. Residual noise check
4. SW and LED check
5. AMP control check
6. VR Check
7. DAC check (includes FET SW (EFFECT)inspection)
8. DSP thru check
9. Analog mute check (FET SW (DIRECT)inspection)
10. Version check
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3. Test contents
1. IC check
1. When you enter test mode, the DSP(IC5) and EEPROM(IC4) check will
begin automatically.
2. If no problem is found, the EFFECT ON/OFF LED, MANUAL LED, and
MEMORY LED will light.
3. If a problem is found, the LEDs will indicate the problem as follows.
ON/OFF LED blinking: EEPROM errorMANUAL LED blinking: DSP(PRAM) error
MEMORY LED blinking: DSP(IRAM) error
If a problem is found, the unit will remain in this state, and it will not be
possible to carry out the remaining tests.
2. Switching noise / shock noise check
1. With the EFFECT ON/OFF LED, MANUAL LED, and MEMORY LED lit,
connect a short plug (47k) to INPUT, and a monitor speaker to OUTPUT.
2. Press the EFFECT ON/OFF switch several times, and verify that no
abnormal switching noise occurs.
3. Press the EFFECT ON/OFF switch to make the EFFECT ON/OFF LED
go dark (ANALOG BYPASS), and drop the unit from a height of
approximately 10 cm to subject it to physical shock. Verify that noabnormal noise occurs.
4. Press the EFFECT ON/OFF switch to make the EFFECT ON/OFF LED
light (DSP THRU), and drop the unit from a height of approximately 10
cm to subject it to physical shock. Verify that no abnormal noise occurs.
3. Residual noise check
1. Connect a noise meter to the OUTPUT.
2. Press the EFFECT ON/OFF switch to make the EFFECT ON/OFF LED
light (DSP THRU), and measure the residual noise.
Verify that the value detected by the noise meter is below -73 dBm (IHF-A).
3. Press the EFFECT ON/OFF switch to make the EFFECT ON/OFF LED
go dark (BYPASS), and measure the residual noise.
Verify that the value detected by the noise meter is below -104 dBm (IHF-A).
4. SW and LED check
1. Press the VARIATION switch, and you will proceed to the switch and
LED check.
First verify that only the VARIATION LED is lit.
The other LEDs will be dark.
Press the switches in the following order, and verify that in a similar
way, only one LED at a time is lit.
2. Press the AMP CTRL switch, and verify that only the AMP CTRL LED is lit.
3. Press the MEMORY WRITE switch, and verify that only the EFFECT
ON/OFF LED is lit.
4. Press the MEMORY WRITE switch, and verify that only the MANUAL
LED is lit.
5. Press the MEMORY WRITE switch, and verify that only the MEMORY
LED is lit.
6. Press the MEMORY SELECT switch, and verify that only the MEMORY 1
LED is lit.
7. Press the MEMORY SELECT switch, and verify that only the MEMORY 2
LED is lit.
8. Press the MEMORY SELECT switch, and verify that only the MEMORY 3
LED is lit.
9. Press the MEMORY SELECT switch, and verify that only the MEMORY 4
LED is lit.
(It is not possible to proceed to other test items before you have finished
the above procedure.)
5. AMP control check
1. Connect the AMP CTRL jack to the channel switching jack of the guitaramp.
2. Verify that the guitar amp channel is switched each time you press the
AMP CTRL SW.
6. VR check
1. Turn the DRIVE volume from MIN to MAX, and verify that the
MEMORY 1-4 LEDs are all dark when the volume is at MIN (the instant
you begin turning the volume), and light correspondingly as you turn the
volume, so that all LEDs are lit when you reach MAX.
(Each VR you operate here must be left at the MAX position so that you
will be able to proceed to the next test item.)
In the same way, perform this test in the following order for the other
VRs.
2. BOTTOM volume
3. TONE volume
4. LEVEL volume
5. ATTACK SHAPE volume
6. HEAVY OCTAVE volume
7. With the TYPE volume turned all the way to the left, turn it toward the
right one click at a time, and verify that the LEDs change as follows.
(TABLE A)
dark lit
(TABLE A)
TYPE EFFECT MANUAL MEMORY VARI AMPCTRL MEM1 MEM2 MEM3 MEM40 (OD-2/OD-1)
1 (BD-2/DS-1)
2 (HM-2/MT-2)
3 (BOOST/LEAD)
4 (CRUNCH/STACK)
5 (METAL/LOUD)
6 (T-SCREAM/FULL-D)
7 (DST+/CENTA OD)
8 (GUV DS/P-RAT)
9 (R-MAN/MUFF FUZZ)
10 (FACE/OCT FUZZ)
8/3/2019 Boss OD-20T Service Notes
15/21
15
OD-20(T)
7. DAC check
1. Set the TYPE volume to BD-2/DS-1.
2. Connect an oscilloscope to OUTPUT, and check the output waveform
(DSP oscillation).fig.1
(200mV/div, 1msec)
3. Press MEMORY SELECT. The MEMORY 4 LED will go dark, and the
output signal will be muted. Verify that the signal is less than -67 dBm
(IHF-A).
4. Connect an oscilloscope to LINE OUT/PHONES, and check the L and R
output waveform (DSP oscillation).fig.2
(200mV/div, 1msec)
5. Press MEMORY SELECT. The MEMORY 4 LED go dark, and the output
signal will be muted. Verify that the noise for L and R is less than -68 dBm
(IHF-A).
8. DSP thru check
1. Set the TYPE volume to HM-2/MT-2.
2. Connect an oscillator to INPUT, and input a 344 Hz, 50 mVp-p square
wave.
3. Connect an oscilloscope to OUTPUT, and check the output waveform.fig.3
(500mV/div, 1msec)
9. Analog mute check
1. Set the TYPE volume to BOOST/LEAD.
2. Connect an oscillator to INPUT, and input a 344 Hz, 50 mVp-p sine wave.
3. Connect an oscilloscope to OUTPUT, and check the output waveform.fig.4
(20mV/div, 1msec)
4. Press MEMORY SELECT. The MEMORY 4 LED will go dark, and the
output signal will be muted. Verify that its level is less than -77 dBm
(IHF-A).
8/3/2019 Boss OD-20T Service Notes
16/21
Apr.2002
BLOCK DIAGRAM
fig.block
INPUT
DC IN
OUTPUT
AMP CTRL
LINEOUT/PHONES
IC2
CODEC
IC3AMP
FET SW
Q2
Q8
FET SW
BUFFER
Q3
AMP,LPF
IC11
TR SW
Q4,Q5,Q7
IC6
CPU
RESET
IC7
IC5
DSPCOMPARATOR
IC10
Q10
FILTER
IC8
DC-DC CONVERTER
Q11,
EEPROM
IC4
BUFFER
Q1
PRE EMPHASIS
AF/AD
IC1
BUFFER
Q12
DE EMPHASIS
BATTERY CN4
TR SW TR SW
Q6Q9
-9V
CN3CN5
WIRING 10P
WIRING 15P
CN1
CN2
CN1
CN2
VR1,VR2,VR3,VR4
VR5,VR6,VR7
SW1,SW2,SW3
SW4,SW5,SW6
LED1,LED2,LED3,LED4
LED5,LED6,LED7,LED8
LED9,LED10,LED11,LED12
RIBON CABLE
PANEL BOARD
JACK BOARD
3pin +A 9
+D 3 . 3
JK1
1
23
JK2
1
23
JK4
1
23
JK3
1
23
JK5213
X211.2896MHz1
2
X1
8MHz
1 2
1
2
3
1 2
1 2
16 17
8/3/2019 Boss OD-20T Service Notes
17/21
18
Apr.2002
CIRCUIT BOARD(JACK)Circuit_Jack-1.eps
Circuit_Jack-2.eps
8/3/2019 Boss OD-20T Service Notes
18/21
19
OD-20(T)
CIRCUIT BOARD(PANEL)Circuit_Panel.eps
8/3/2019 Boss OD-20T Service Notes
19/21
Apr.2002
CIRCUIT DIAGRAM(JACK)
fig.jack
GUITAR INPUT
DC IN
TO BATTERY
OUTPUT
AMP CTRL
148/40usPre-Emphasis
DC IN
td=48ms
PHONES/LINE
LED_POWER
LED_AMP_CTRL
CA3
CA3
LED_ON/OFF
LED_4
LED_4LED_3
LED_MEMORY
LED_VARIATION
LED_MANUAL
LED_ON/OFFLED_MANUALLED_MEMORYLED_AMP_CTRLLED_VARIATION
LED_3
CA4
CA4
LED_2
LED_2
P03P04
LED_1
LED_1
VR_TONE
VR_ATTACKVR_OCTAVE
VR_LEVEL
VR_BOTTOM
VR_TYPEVR_DRIVE
CA1CA0
CA1
CA2
CA0
CA2
SW_ON/OFF
SW_VARIATION
SW_ON/OFF
SW_AMPCTL
SW_WRITE
SW_MAN/MEMSW_VARIATION
SW_MAN/MEM
SW_AMPCTL
SW_SELECT
SW_SELECTSW_WRITE
P04P03
+
+D 3 .3
D
+D 3 .3
A
+D 3 .3
D
+
AA
+
+D 3 .3
+
A
+
A
A
+
AA
+
+D 3 .3
+ +
+
+
+
A A A
+
D
+D 3 .3
D
D
+D 3 .3
D
D
D
+D 3 .3
D
D
+D 3 .3
+D 3 .3
D
+D 3 .3
D
+D 3 .3
+D 3 .3
D
D
D
+D 3 .3
D
D
+D 3 .3
D
+D 3 .3
AD
D
+D 3 .3
D
D
-
A
A
D
+
A A A
+
+D 3 .3
D
D
+D 3 .3
D
D
D
+D 3 .3 +
D
DD
-
+
A
A
A
A
A
A
A
A
+
A
+
+
A
+D 3 .3
D
+D 3 .3
+
A
A
A
R110k
C1
0.47S
Q12SK880GR
3
1
2
L3SLF7045T-151MR37-2(150uH)
IC8S-8520E33MC-BJS-T2
ON/OFF1
VIN5
VSS2
EXT4
VOUT3
D7SS14
C76100/16
CN3
11
22
33
RIBON CABLE 2mm 3P
11
22
33
D5SS14
IC2 AK4552VT
LIN2
SDTO8
RIN1
VD5
MCLK11
BCLK12
PDN 13
DEM17
VCOM14
LRCK10
VSS3
SDTI9
DEM06
VA4
ROUT16
LOUT15 +
-
IC3BM5218AFP
6
57
R2512k
R3412k
D41SS355
1
2
Q82SK879Y
3
12
Q10 2SC4116GR
1
23
C790.1
C510.1 C54
100/16
C52100/16
C530.1
C77 0.1
C330.047
R45100k
R51M
R61k
Q11 IRF7606
S2 D 7
S3
D5
G4
S1
D8
D6
R23 15k
C12 270p
R3615k
C22270p
R29
1M
C4
10/16
Q22SK879Y
3
12
D11SS355
1
2
R271M
R2147k
C170.047
R28100k
R2
1M
R3
1M
R30
39k
R26 47k
C13 270p
R1710k
C90.0022
C191/50
R4470k Q3
2SC3324GR1
2
3C31/50
C21/50
C31100/16
C320.1
R4010k
R4610k
C2010/16
C210.1
R3510k
R3310k
+
-
IC1CNJM2100M
8
4
C35
0.1
R49
10k
R50
10k
C42 0.1
C44 0.1
C46 0.1
C40 0.1
C38 0.1
C6918pX2
CX-49G11.289 6MHz
C67 0.068
C43 0.1
C45 0.1
C47 0.1
C36 0.1
R611k
C34 47/16
R54 33
R601M
IC5TC220C120AF-006(MR3)
OSC1
VSS
2
OSCSEL3
VSS
4
XTO5
XTI6
VDD
7
DIVS08
DIVS19
PLLBP10
VSS
11
VSS
12
TESTP13
VDD
14
VDD15
PLLVAA16
PLLRO17
PLLLP18
PLLAGS19
PLLAGD20
VSS
21
VSS
22
VDD
23
VDD
24
RST25
VSS
26
CD727
CD628
CD529
CD430
VSS
31
TESTS32
VDD
33
CD334
CD235
CD136
CD037
VDD
38
DRQ39
INT040
INT141
DRST42
VSS
43
CA444
CA345
CA246
CA147
CA048
VDD
49
RD50
CS51
VSS
52
WR53
VSS
54
DIV55
VDD
56
DA057
AD058
VDD
59
BCK60
VSS
61
LRCK062
LRCK163
VDD
64
MCK65
VSS
66
DA167
AD168
DA269
AD270
VSS
71
CTYPE72
VDD
73
DA374
AD375
SYI76
TESTB77
TESTT78
VDD
79
VSS
80
C640.1
X149USSMD18MHz
C70 22p
C68 22p
R51
100
C58
0.0
1
C57
0.0
1
C59
0.0
1
C60
0.0
1
C56
0.0
1
C55
0.0
1
C61
0.0
1
IC4
CAT24WC02J
A01
A12
A23
VSS4
SDA5
SCL6
WP7
VCC8
R1827 (2W)
R3710
C240.1
C2310/16 C25
10/16C260.1
C300.1
C291/50
JK1
HTJ-064-12D
1
23
C5
0.0022 C6 100p
C710/16
R16
47k
R8
47k
+
-
IC1ANJM2100M
2
31
R12
10k
+
-
IC1BNJM2100M
6
57
R20150k(F)
R24
10k(F)
TP1 TH1
TP2 TH1
R5347k
R5247k
JK2
HTJ-064-12D
1
23
RIBON CABLE 2mm 3P
11
22
33
C810/16
C1510/16
C1610/16
Q52SA1298Y
1
3
2
R1310k
Q42SA1586GR
1
3
2
R1510k
R1110k
R3210k
C48NFM4516P13C204F
JK6 DJ-0711-020213
JK5 KM02009_B213
R572.2k
Q72SC3265Y
1
2
3
R48miniSMDC075
C1010/16
C110.1
R1410k
R1910k
L2SLF7032T-4R7M1R7-2 (4.7uH)
IC6 M N101C30A
LED3/D3/P8357
LED2/D2/P8258
LED1/D1/P8159
LED0/D0/P8060
AN0/PA062
AN1/PA163
AN2/PA264
AN3/PA31
AN4/PA42
AN5/PA53
AN6/PA64
AN7/PA75
VDD7
OSC28
OSC19
VSS10
P22/IRQ229
P23/IRQ330
P24/IRQ431
P67/A744
P27/RST21
MMOD13
LED7/D7/P8753
LED6/D6/P8654
LED5/D5/P8555
LED4/D4/P8456
P66/A643
P65/A542
P64/A441
P63/A340
P62/A239
P61/A138
P60/A037
P70/A845
P71/A946
P72/A1047
P73/A1148
P74/A1249
P75/A1350
P76/A1451
P77/A1552
P21/IRQ1/SENS28
P20/IRQ027
VREF+6
VREF-61
X111
X012
P50/WE32
P51/RE33
P52/CS34 P53/A16
35P54/A17
36
P14/TM4IO26
P13/TM3IO25
P11/TM1IO23
P12/TM2IO24
P10/TM0TO/RMOUT22
P06/BUZZER/DK20
P05/SBT119
P04/SBI118
P03/SBO117
P02/SBT016
P01/SBI0/RXD15
P00/SBO0/TXD14
C78100/16
C1410/16
C1810/16
RA5 1001 82 73 64 5
D61SS355
1
2
C720.01
R62330
D9
N.I.U.
1
2
D802DZ5.1Y
1
2
RA6 100
1 82 73 64 5
R5547k
R5647k
CN2
A2001WR2-15P
11
22
33
44
55
66
77
88
99
1010
1111
1212
1313
1414
1515
RA447k
1
8
2
7
3
6
4
5
RA2 680
1 82 73 64 5
RA3 680
1 82 73 64 5
Q62SC4116GR
1
2
3
R41
47k
R44
1M
Q92SC4116GR
1
2
3
R3147k
R4747k
R5810k
C800.001
R2227 (2W)
JK4
HTJ-064-12I
1
23
CN4
53015-0210
11
22
C39 0.1
C41 0.1
C37 0.1
R10100k
+
-
IC3AM5218AFP
2
31
+
-
IC3CM5218AFP
8
4
C840.1
R73 10k
R75
100k
R78
100k
R74470k
+
-IC10C
M5216FP
8
4
R7710
C9310/16
C65
10/16
C74 47/16
C6310/16
+
-
IC10B
M5216FP
6
57
C750.1
+
-IC10A
M5216FP
2
31
C7122p
C660.1
C620.1
R79
10
C94
1/50
D10
1SS355
1 2
C91 1/50
DA3 1SS30221
3
R76
10
C92100/16
+
-IC11A
M5216FP
2
31
R82100k
R83100k
C950.0018
R65330
R94.7k
+
-IC11B
M5216FP
6
57
R86100k
R87100k
C90150p
R69330
R67100k
C87
0.22/50
C49
100/16
C50 0
.1
C83150p
C88150p
C85150p
R710k
JK3
HTJ-064-12D
1
23
C81
100/16
R 81 1 0k
R8010k
R664.7k
R8410k
R 85 1 0kC890.0018
C86
100/16
R64
68(1/2W)
R68
68(1/2W)
R7 2 68 0
+
-IC11C
M5216FP
8
4
D2
1SS352
D3
1SS294
R88 4 .7kR 59 2 7k
CN1
A2001WR2-10P
11
22
33
44
55
66 77
88
99
1010
R7010k
C730.1
IC7
S-80930CLMC
OUT1
Cp5
VDD2
NC4
VSS3
IC12
N.I.U.(S-80130ALMC-JAP-T2)
DS1
GND2
NC3
VDD5
OUT4
Q122SC3324GR1
2
3
R100
10k
R10110k
R102100k
R103100k
C100 N.I.U.
C101 N.I.U.
C102 N.I.U.
20 21
8/3/2019 Boss OD-20T Service Notes
20/21
Apr.2002
CIRCUIT DIAGRAM(PANEL)
fig.panel-c
(50KB) (50KB) (50KB) (50KB)
EFFECTON/OFF MANUAL
(50KB) (50KB)
MEMORY VARIATION 1234
DRIVEBOTTOMTONELEVELATTACK
OCTAVETYPE
AMPCTRL
EFFECTON/OFF
MAN/MEM VARIATION AMP CTRL WRITE SELECT
(50KB 11click )
SHAPE
HEAVY
(CENTER CLICK)
+D 3 . 3
D
+D 3 . 3
D
+D 3 . 3 +D 3 . 3 +D 3 . 3 +D 3 . 3 +D 3 . 3 +D 3 . 3+D 3 . 3 +D 3 . 3
D
+D 3 . 3
D D D D D D D
+D 3 . 3
VR2
RD901-40-125F-B54-0CD
1
2
3VR4
RD901-40-125F-B54-00D
1
2
3VR1
RD901-40-125F-B54-00D
1
2
3VR3
RD901-40-125F-B54-00D
1
2
3VR6
RD901-40-125F-B54-00D
1
2
3VR5
RD901-40-125F-B54-00D
1
2
3VR7
RD901-40-125F-B54-11D
1
2
3
LED12L-113GDT
1
2
LED5
L-34HDSL
1
2
LED6
L-312LRD
1
2
LED8
L-34HDSL
1
2
LED9
L-34HDSL
1
2
LED10
L-34HDSL
1
2
LED11
L-34HDSL
1
2
LED3
L-34HDSL
1
2
LED4
L-34HDSL
1
2
LED7
L-312LRD
1
2
C1 N.I.U.
SW1
SKQKAH1
2
SW2
SKQKAH1
2
SW3
SKQKAB1
2
SW4
SKQKAB1
2
SW5
SKQKAB1
2
SW6
SKQKAB1
2
CN2
WIRRING 15P
11
223 3
44
55
66
77
88
99
1010
1111
1212
1313
1414
1515
CN1
WIRRING 10P
11
22
33
44
55
66
77
88
99
1010
22 23
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Apr.2002