BOSS DD-20 Service Manual
Mar.2003
TABLE OF CONTENTS
SPECIFICATIONS.............................................................2
LOCATION OF CONTROLS ..........................................4
LOCATION OF CONTROLS PARTS LIST ...................5
EXPLODED VIEW ............................................................6
EXPLODED VIEW PARTS LIST ..................................... 9
PARTS LIST......................................................................10
CHECKING THE VERSION NUMBER.......................14
RESTORING THE FACTORY SETTINGS...................14
DD-20(T)
SERVICE NOTES
Issued by RJA
TEST MODE.....................................................................14
BLOCK DIAGRAM.........................................................22
CIRCUIT BOARD (JK-A) ...............................................24
CIRCUIT BOARD (JK-B) ................................................25
CIRCUIT BOARD (PANEL-A)......................................26
CIRCUIT BOARD (PANEL-B).......................................27
CIRCUIT DIAGRAM (JACK) ........................................28
CIRCUIT DIAGRAM(PANEL)......................................30
Copyright © 2003 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 (0800) (NB)17058152E0
Mar.2003
SPECIFICATIONS
DD-20: DIGITAL DELAY
Nominal Input Level
• 20 dBu (GUITAR/BASS)
+4 dBu (AMPLIFIER SEND/RETURN)
Input Impedance
1 M[ohm]
Nominal Output Level
• 20 dBu (GUITAR/BASS)
+4 dBu (AMPLIFIER SEND/RETURN)
Output Impedance
1 k[ohm] (OUTPUT A (MONO), B)
33 [ohm] (PHONES)
Recommended Load Impedance
10 k[ohm]
Residual Noise Level
• 93 dBu or less (IHF-A typ.)
* E. LEVEL/F. BACK/TONE knobs are set to the center position
Connectors
INPUT A (MONO) Jack (1/4 inch phone type)
INPUT B Jack (1/4 inch phone type)
PHONES Jack (stereo 1/4 inch phone type)
CTL PEDAL Jack (1/4 inch phone type)
OUTPUT A (MONO) Jack (1/4 inch phone type)
OUTPUT B Jack (1/4 inch phone type)
AC Adaptor Jack
Power Supply
Dry battery (R6/LR6 (AA) type) x 6: DC 9V
AC Adaptor (DC 9V)
Current Draw
200 mA (9 V max.)
* Expected battery life under continuous use:
Carbon: 2 hours
Alkaline: 7 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
1.2 kg / 2 lbs 11 oz (including batteries)
Display
Custom LCD (with backlit)
Controls
ON/OFF Pedal
MEMORY/TAP Pedal
DELAY TIME Knob
E.LEVEL Knob
F. BACK Knob
TONE Knob
MODE Knob
TAP Button
TEMPO Button
MEMORY WRITE Button
MEMORY SELECT Button
Indicators
POWER Indicator
(serves also as battery check indicator)
ON/OFF Indicator
MEMORY Indicator
TAP Indicator
MANUAL Indicator
MEMORY Number Indicator 1-4
TEMPO Indicator
Accessories
Owner’s Manual JAPANESE:(#G6017365)
ENGLISH:(#G6017366)
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.
2
DD-20(T)
3
Mar.2003
LOCATION OF CONTROLS
fig.panel-p
21
18 19
B
20
2
L
M
22
7
16
17 N
336H
1
4
A
C
C
D
5
I
J
15
E
9
F
G
10
K
D
11
4
8
1213 14
LOCATION OF CONTROLS PARTS LIST
Part Code Part Name Description
No.
1 G2477122 R-KNOB
2 H5029855 SCREW M4X8 HEXAGON BUTTON HEAD NI
3 G2567155 ENC ESC
4 G2477130 ENC KNOB
5 G2497001 KEYTOP S(RED)
6 G2567156 LCD PANEL
7 G2217180 PANEL
8 G2217181 LED PANEL
9 H5029851 PEDAL SHAFT
10 G2357116 PEDAL PLATE 62X53
11 H5029852 SCREW 4M3 FEBZC HEXAGON SOCKET BUTTON HEAD
12 75E041R000 PEDAL R
13 75E041L000 PEDAL L
14 75E041C000 CASE
15 G247751301 VGA KEYTOP S WITHOUT LENS
16 G2217182 REAR PANEL
17 G2537731 QUICK MANUAL LABEL
18 G2017621 BATTERY COVER
19 75D422E000 BOTTOM COVER
20 G2357118 BOTTOM FOOT
21 40123545 JACK NUT 9X11X2 HLJ0999-01-240 NI
22 40016467 JACK WASHER M9.2X14X0.5 FENI
A 03231912 ROTARY ENCODER W/SW
B F3279802 POTENTIOMETERNO CLICK 50KB RD901-40-125F-B54-00D
C F5029106 LED (GREEN) L-32GDSL
D 1502928100 LED (RED) L-34HDSL
E F5029133 LED (BLUE) L-934MBD
F F3129306 SWITCH SKQKAB
G F5029126 POWER LED L-113GDT
H F5029414 LCD DC-320 A
I F3279819 ROTARY POT. W/CENTER CLICK RD901-40-125F-B54-0CD 50KB
J F3279803 POTENTIOMETER 11 CLICKS 50KB RD901-40-125F-B54-11D
K 13129778 TACT SWITCH SKQKAH
L F3449707 PHONE JK(STREO) HTJ-064-12DS
M 13449150MF PHONE JACK (STEREO) HTJ-064-12D
N F344941501 ADAPTOR JK KM02009BB
R-ENCODER EVQB1SZ1720B
DD-20(T)
5
Mar.2003
EXPLODED VIEW
FIG.EXPLO2
16
12
18
11
a
10
a
13
14
15
17
j
6
18
11
BBBBGGGG2222222233
DD-20(T)
33
b
21
27
k
44
43
28
45
f
e
25
23
b
26
1
c
20
m
n
22
24
1
32
29
33
32
30
31
45
7
Mar.2003
fig.explo3
7
6
RIGHT SIDE
h
2
8
LEFT SIDE
9
g
1
5
i
3
4
8
EXPLODED VIEW PARTS LIST
[PARTS]
No.
1 75E041C000 CASE 1
2 G2357111 CUSHION R 2
3 H5029851 PEDAL SHAFT 2
4 2215770201 PEDAL GUIDE BUSH 215-702 2
5 2217710900 COIL SPRING 217-109 2
6 G2357116 PEDAL PLATE 62X53 2
7 G2357115 PEDAL FOOT M8 2
8 75E041R000 PEDAL R 1
9 75E041L000 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 G2537731 QUICK MANUAL LABEL 1
20 G2477130 ENC KNOB 1
21 G2477122 R-KNOB 4
22 G2567155 ENC ESC 1
23 G2257129 INSULATING SHEET CENTER 1
24 G2217180 PANEL 1
25 G2217182 REAR PANEL 1
26 G2217181 LED PANEL 1
27 G2567156 LCD PANEL 1
28 G2197127 JACK SPACER 1
29 F5029414 LCD DC-320 A 1
30 G224780201 DIFFUSION SHEET 1
31 F5029410 LCD BACKLIT 43.3X23.6 1
32 G247751301 VGA KEYTOP S WITHOUT LENS 3
33 G2497001 KEYTOP S(RED) 1
43 G2147807 JACK HOLDER 1
44 75E041M000 JACK BOARD ASSY 1
45 75E041P000 PANEL BOARD ASSY 1
Part Code Part Name Description Q’ty
DD-20(T)
[SCREWS]
No. Part Code Part Name Description Q’ty
a H5029115 SCREW 3X8 PAN TATITE FEBZC 7
b H5019110 SCREW M3X6 PAN TAPTITE FEZC 13
c H5029855 SCREW M4X8 HEXAGON BUTTON HEAD NI 4
e 40016467 JACK WASHER M9.2X14X0.5 FENI 6
f 40123545 JACK NUT 9X11X2 HLJ0999-01-240 NI 6
g H5029852 SCREW 4M3 FEBZC HEXAGON SOCKET BUTTON HEAD 2
h H5039413 NYLON WASHER M4.1X7.5X0.5 BLACK 2
I H5039413 NYLON WASHER M4.1X7.5X0.5 BLACK 2
j H5019430 SCREW M2.6X5 BINDING HEAD TAPTITE P FEZC 2
k H5039521 VR ACCESSORY NUT M7 4
m H5039521 VR ACCESSORY NUT M7 1
n H5039127 VR WASHER M7 1
9
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