
MXD120/H/Twin
Service InformationService Information
Laney
Classic British Amplification
Newlyn Road, Cradley Heath, West Midlands. B64 6B£
www.laney.co.uk

1
MJACK
G
SK1
GG
A A
B B
Input
C4
4N7 1 00V
R1
10K
R2
1M
G G
+15V
C2
-15V
47P 50V
D1
1N41 48
D2
1N4148
C7
G
+15v
TL072
-15V
R4
C6
270P 250 V
2U2 6 3V
R6
4K7
U1A
22K
FootSwitch
2
0R0
C9
R21
LN1
150K
10N 1 00V
SK3
SJACK
G
AA
R19
100K
CD4069UBE
VDD
147
1 2
U2A
G
Clean Channel
C12
3N3 5 0V
Treble
VR4
R9
10K
22KB6S
C14
220N 63 V
Bass
VR2
100K A6S
220N 63 V
Mid
C13
VR3
C10
100N 63 V
2K2B6S
G
100N 63V
C19
100K A6SD
LN2
0R0
G
VR5A
1N41 48
G
Drive Channel
R8
100K
Hard wire on top side of pcb
-15V
R16
10K
SW1A
2P2WPS
G
SW1B
2P2WPS
G
Channel Select
3
Q2
2N38 19
D7
TL072
R3
10K
G
Drive On
R13
1K
D4
3V9 Z D0. 5W
R18
100K
G
R5
33K
C17
10N 100V
U1B
-15V
G
R20
47K
C8
100N 63 V
D5
LED3MMG
R15
2K2
TS2
BC307
R24
1M
U2B
3 4
CD4069UBE
VR1
100K A6S
G
R14
G
100K
R12
470K
G
C5
1N 10 0V
C15
100N 63V
C20
100N 63 V
VR5 B
100K A6SD
-15V
G
4
R11
10K
TS1
BC307
U2C
5 6
R22
47K
CD4069UBE
C18
100N 63V
R10
100K
R25
1M
22N 100V
R7
220K
C11
100N 63 V
G
5
C21
47P 50V
R23
1M
U2D
C22
R26
220K
Q1
2N38 19
9 8
CD4069UBE
D3
1N41 48
LN7
0R0
R36
3K3
220N 63V
220N 63V
C28
C31
100N 63V
LN3
0R0
C32
3N3 5 0V
C23
Treble
G
VR9
22KB6S
Bass
VR7
100K A6S
VR8
2K2B6S
Mid
+15V
TL072
-15V
R33
10K
SW2B
R35
10K
G
6
R29
10K
U3A
2P2WPS
Max On/Off
R28
6K8
2P2WPS
SW2A
100N 63V C25
R34
10K
G G
R37
15K
C27
4N7 1 00 V
R30
15K
TL072
R32
10K
1N 10 0V
U3B
C26
100K A6S
VR6
Master Volume
R31
22K
C24
47N 100V
LN6
0R0
G
R27
220K
7
Tape/CD In
SK2
G
G
PHONOSTV
Q3
2N38 19
D8
1N41 48
LN5
Top
Bot
0R0
R43
22K
R46
22K
R48
10K
G
R38
220K
LN8
0R0
TL072
G
FXSEND
FXRETURN
DSP Level
8
R52
100K
D10
1N41 48
R40
100K
100K
LN12
0R0
D9
1N41 48
LN15
0R0
C30
47P 50V
R39
100K
U4B
TL072
LN9
0R0
G
R41
+15V -15V
C29
47P 50V
-15V
U4A
+15V
R50
1K
VR1 0
22KB6S
G
LN14
C C
TO OUTPUT PCB
9353/9391
Programming He ader
HD2
123456
PTA0
PTA1
PTA2/IRQ
PTA3
PTA4
D D
PTA5/OSC
FX Return
FX Send
123456
+5VDSP
-15V
G
HD1
1
DSP Program Select
SW3
16PGRY
1
2
3
4
C
FXRETURN
FXSEND
+15V
G
LN16
0R0
NOTE:
2
HD6WL
HD3
123456
R44
R45
R51
330R 5W
LN10
0R0
C38
10U 5 0V
G
15V Z D1. 3W
560R 5W
560R 5W
15V Z D1. 3W
+15VDSP
15V Z D1. 3W
G
D11
D14
G G
D12
G G
IN OUT
GND
G
U5
7805
LN11
0R0
C36
47U 5 0V
C37
47U 5 0V
G
C3
-15V
100N 63V
C1
100N 63 V
G
+5VDSP
C33
C34
100N 63 V
10U 5 0V
3
+15V
+15V
R17
1K
G
D6
5V1 Z D0. 5W
4
VDD
G
C16
470U 16 V
-15V
R49
4K7
D13
LED3MMR
Power
G
Line Out
G
SK4
MJACK
C35
R47
100K
R42
1K
6
G
2U2 6 3V
G
5
0R0
NOTE: MXD65 / R51 = 270R
NOTE: MXD120 / R51 = 330R
NOTE: All resistors to be 1/4W unless otherwise stated
NOTE: All capacitors to be rated at 16V or higher
Title
MXD65 / MXD120 PREAMP
Number Revis ionSize
A3
Date: 10/1 0/2 003 Sheet of
File: C:\D ocu ments and Sett in gs\..\9387_6 .Sch Drawn By:
9387 6
7
119387_6.Sch
Rich Thompson
8

1
A A
2
3
4
5
6
7
8
+40V-40V
HD1
123456
To Preamp PCB
HD6WL
B B
C C
G
HARDWIRED SOCKET
Wir e d D i rec t to O u tp ut PC B
FX Sen d
SK2
MJACKGSJ
FX Retur n
Gi
R3
1K
Q1
2N38 19
Gmu
C5
100U 25V
Gmu
Gmu
Gi
D4
1N41 48
TS8
MPSA42
C1
2U2 6 3V
D2
3V9 Z D0. 5W
D1
3V9 Z D0. 5W
R12
10K
Gmu
Gi
R13
33K
OFFSET ADJ
C2
R4
10K
1N 10 0V
Gi
C6
1U 63 V
Gmu
Gi
G
100R
LN10
0R0
+45V
R9
100R
R8
TS4
MPSA92
1K
TS2
MPSA92
R1
VR1
1KH
TS1
MPSA92
R7
220R
R2
100R
TS3
MPSA92
Gi
R6
100R
100P 100 V
C3
47U 5 0V
C4
-45V2
LN5
0R0
R5
100K
TS5
MPSA42
LN3
0R0
R10
2K2
R16
330R
R15
10K
-45V2
C7
47P 50V
LN4
0R0
LN8
0R0
R11
220R
TS6
MPSA92
D3
1N41 48
TS9
MPSA42
TS10
MPSA92
D7
1N41 48
2U2 6 3V
TS7
SAP16N
100N 63 VC10
R17
330R
1N41 48D6
R18
6K8
C11
6K8R19
330RR20
100N 63 VC13
G
G
1N41 48D8
TestPoint1
BIAS ADJ
TestPoint2
LN9
0R0
R22
220R
VR2
470RH
R14
0R22 5W
R21
0R22 5W
SAP16P
TS11
-45V
D5
1N40 07
D9
1N40 07
C16
47N 1 00V
R23
10R 2W5
G
R24
10R 2W5
L1
COIL20T
Extension Loudspeak er
Internal Loudspeak er
SP4
SPADE 4.8
SP6
SPADE 4.8
R29
R28
0R22 5W
220R
G
SK4
MJACKSJ
Head Version Only!
Mai n s T ra nsf orm er
230V = 5600-2050B
120V = 5600-2052B
MAINS FUSE 230V =T2A L, 115V = T5A L
Mains In
IEC Inlet
Green/Yellow
D D
Flame proof resister
FP
Must only be replaced with same type and rating
Indicates safety critical component
Must only be replaced with approved type
Black(Brown)
Fuse Integral to IEC
White (Blue)
Chassis Transformer Primary
1
Fuse
Mains Switch
AC Line(Live)
AC Input (Neutral)
NOTE:
Set VR5 to give 20mV across TP1 and TP2
Refer to service manual before adjusting bias preset
2
MAINS TRANSFORMER
These items not on pcb
3
SP3
SPADE4.8
SP1
SPADE4.8
SP2
SPADE4.8
G
4
1N40 07
C15
220N 250V
LN6
0R0
D11
D10
BR1
1N40 07
+V
AC
AC
-V
6A 20 0V
+45V
C9
C14
100N 63V
4700 U 63V
G
-45V
5
C12
4700 U 63V
-45V2
C8
100N 63V
Gmu
LN7
0R0
R26
10R 2W5
R25
10R 2W5
6
BLT
Industries
+40V
G
-40V
Title
MXD120 OUTPUT
Number Revis ionSize
A3
Date: 23/1 0/2 003 Sheet of
File: D:\93 91_3\93 91 _3. Sch Drawn By:
9391 3
7
119391_3.Sch
Rich Thompson
8