Mark Bass LITTLE MARK III User manual

2009 EDITION
LITTLE MARK III
COMBO HEAD II
SERVICE MANUAL

How to disassemble the LMIII / CHII preamp
1. Remove the six black knobs and the three yellow knobs pulling out as
indicated in the picture (red arrow).
2. Remove the nine silver hexagonal nuts using a 10 or 11 mm nut
screwdriver.
3. Remove the black hexagonal nut using a 15 mm nut screwdriver
(see yellow arrow).
4. Remove the four connectors from the preamp (yellow arrows).
5. Remove the three screws (red arrows).

How to disassemble the LMIII / CHII poweramp
1. Remove the four connectors (yellow arrows).
2. Cut the two ties (green arrows).
3. Remove the six screws (red arrows).
How to disassemble the LMIII / CHII front panel
components
1. Remove the two screws with a 2.5 mm hexagonal wrench (red arrows).
2. Remove the four faston connectors (red circle).
3. Press on the top and bottom ends of the power switch (red arrows) to
remove it from the panel.

HowtoDisassembletheLMIII/CHIIrearpanelcomponents
1. Remove the four hexagonal nuts using a 15 mm nut screwdriver
(green arrows).
2. Using a screwdriver, remove the two screws of the line out jack
and the two screws of the speaker out speakon combo jack
(yellow arrows).
3. Using a screwdriver, remove the four screws of the fan (red arrows).
4. Using a screwdriver, remove the screw of the back panel (red arrow)
and remove the 20-pin flat connector (yellow arrow).
5. Remove the ground hexagonal nut (red circle) using a 7 mm nut screw
driver.
6. Press on the top and bottom (red arrows) ends of the AC power jack
to remove it from the panel.

Effects Loop Modification
The images below show how the effects loop in your amp can be modified
to run in series.
The default factory setting is parallel.
PARALLEL CONNECTION
REAR PANEL SECTION
SERIAL CONNECTION
REAR PANEL SECTION
LMIII / CHII PREAMP SECTION
LMIII / CHII PREAMP SECTION

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7654321
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5
Parsek s.r.l.
via Aterno, 30
66020 S. Giovanni Teatino
Chieti
Italy5
Supply - DA510
18-Dec-2008 12:40:39
I:\PSRK\Amplifier\DA510\Edizione_ed.B\DA510_ed_B.DDB - Supply.Sch
Title
Size: Number:
Date:
File:
Revision:
Sheet of
Time:
A3
1
23
T22
IRFP27N60K
1
23
T23
IRFP27N60K
D31
BYV27-200
VCC 1
Rt 2
Ct 3
COM
4
LO
5
Vs 6
HO
7Vb 8
IC5
IR21531D
3
1
4
2
BR1
800V/5A C39
1000uF/200V
C40
1000uF/200V
1 2
CN9
110/220
Vdc
C68
1uF/250V
2
1 3
D25
RF2001T2D
2
1 3
D26
RF2001T2D
2
1 3
D24
RF2001T2D
R78
270K
R76
10
D34
BYV27-200
D39
BYV27-200
C67
10nF/63V
C51
1uF/63V
C72
330pF
R74
18K
2
1 3
D27
RF2001T2D
C47
1000uF/100V
C48
1000uF/100V
R80
47
D32
BYV27-200
R77
10
C69
10uF 35V
D21
12V/1W
C70
100uF 35V
D40
1N4148
Vin 1
GND
2
+15V
3
RG1LM7815CT
Vin 2
GND 1
-15V
3
RG2
LM7915CT
+C64
2200uF
+C65
2200uF
C57
1uF/63V
C58
1uF/63V
+C61
100uF/25V
+C62
100uF/25V
C13
100nF/63V
C54
100nF/63V
35V
D29
BYV27-200
+C66
100uF
1
J3
1
J8
1
J6
1
J7
C52
1uF/63V
C56
1nF/63V
F1
1
2
3
4
5
6
7
8
9
10
CN7
+
+15V
-15V
+15V
-15V
+18V
R73
2,7K
12
D1
-15V
1
J9
1
J10
Input
C50
270pF
R85
100
C49
270pF
R83
100
C71
270pF
R86
10
1
122
3
344
L1
3.3mH/6A
C33
1uF/275Vac_X2
C35 4.7nF/Y1_X2
C36
4.7nF/Y1_X2
C34
47nF/275Vac_X2
t
MV-RT2
2.5Ohm
1
2
CN5
Rete
R69
330K
R71
330K
+80VDC
-80VDC
1
+15V
1
-15V
MV-VR1
275L40
INPUT
15
15
88
33
14
14
13
13
12
12
11
11
10
10
22
11
77
66
18
18
16
16
17
17
9
9
Shield
Tr1
TRANS5_2_1
1
2
CN6
12V
+20V
+20V
Text

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7654321
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1
Parsek s.r.l.
via Aterno, 30
66020 S. Giovanni Teatino
Chieti
Italy2
Ampli Lineare e Protezioni - DA510
18-Dec-2008 12:40:37
I:\PSRK\Amplifier\DA510\Edizione_ed.B\DA510_ed_B.DDB - Ampli.Sch
Title
Size: Number:
Date:
File:
Revision:
Sheet of
Time:
A3
1
2 3
T1
MMBT5551
1
23
T3
MMBT5401
1
23
T5
MMBT5401
1
2 3
T2
MMBT5551
1
2 3
T6MMBT5551
1
2 3
T13
MMBT5551
1
23
T12
MMBT5401
R6
100
R4
100
R5
100
R7
100
R37
1K
R9
4.7K
R8
4.7K
R12
1K
R11
4.7K
R10
4.7K
R13
1K
R39
1K
R14
4.7K
12
3
T7
MJE350
12
3
T11
MJE350
1 2
3
T8
MJE340
1 2
3
T10
MJE340
R15
220
R16
220
C3
47pF
C5
47pF
1
2 3
T9
BC846
1
2
3
TRIM1
R17
8.2K
R38
15
C4
1uF
R18
732
R19
680
R20
680
D4
6.2V
D3
6.2V
D6
6.2V
D5
6.2V
TI1
IRFP240
TI2
IRFP240
TI3
IRFP240
TI6
IRFP9240
TI5
IRFP9240
TI4
IRFP9240
R22
220
R23
220
R21
220
R24
220
R25
220
R26
220
R27 0.33
R28 0.33
R29 0.33
R30
0.33
R31
0.33
R32
0.33
R35
47K
R33
820K
C80.1u
R34
715
C7A
100uF
C7B
100uF
R36
4.7
C6
47nF/250V
R65
15k
+12PROT
1 2
3
T18
BD681
+
C32
47uF/35V
R68 1M 1
23
T21
BC856
1
32
T19
2N7002
1
32
T20
2N7002
1
2
CN1
Speaker Out1
1
2
3
4 5
RL1
RL_OUT_1
+18V
D18 MUR120
OUT
SourceH
SourceL
CTLB
11 CTLA
3
RST A
4
RST B
10
THR A
2
THR B
12
TRIGA
6
TRIGB
8
OUT A 5
OUT B 9
DISC A 1
DISC B 13
VCC 14
GND
7
IC3
NE556N
R59
100
C19
0.1uF/63V
C20
0.1uF/63V
C21
0.1uF/63V
R70
10K +12PROT
+12PROT
C22
0.1uF/63V
R58
10K
R57
10K
t
MV-RT1
10K
R53
1.8K
+12PROT
D13 1N4148
D14
1N4148
1
2 3
T16
BC846
Prot_I
SourceH
SourceL
INPUT
R2
1K
C1
1uF
C2
180pF
R3
47K
12
3
T14
J112
DIS
R60
180K R63
220K
-15V
DIS Prot_I
D7
1N4007
D8
1N4007
C9
33uF
C11
33uF
C10
47n/250V
C12
47n/250V
+80VDC
-80VDC
+15V
-15V
R62
2.2K
12
D16
R61
2.2K
12
D15
R1
1M
1 2
CN3
1 2
CN4
C7
10uF/35V
+12PROT
-80Vamp
+80Vamp
1
2
3
4
CN-Test
CON4
1
12VP
R66
150 2W
1
32
T26
2N7002
R55
10K
C28
10uF/25V
C42
100nF
I-I
Prot_I
R41
10K
+12PROT
1
2
5
4
IC10
H1AA1
R43
100
R44
100
R67
180/2W
+18V
R90
8.2K
+
C31
100uF/35V
1 2
3
T25
MJE340
1
2
3
4
CN2
FAN2
R42
47K
3
2
1
8 4
IC4A
NE5532
+15V
C73
0.1uF/63V
-15VC63
0.1uF/63V
R82
220
R40
22K R81
4.7K
R46
4.7
+15V
C53
1uF/63V
+15V Vin
1
GND
2
+12V 3
RG3
LM7812CT
I-I
RL_Out
RL_Out
Input
5
6
7
IC4B
NE5532
C14
47nF/63V
C15
47nF/63V
C16
47nF/63V
R472.2K
R48
2.2k
1
23
T4
MMBT5401
D9
1N4148
D2
1N4148
D10
1N4148
R45
4.7k
D11
1N4148
R50
100
R49
3.9K
+15V
t
MV-RT3
10K
C17
0.1uF/63V
D12
1N4148
R51
47K
+12PROT
C30
100uF
+
C29
1uF/35V
+12PROT

1 2 3 4 5 6
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D
6
54321
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B
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2
Parsek s.r.l.
via Aterno, 30
66020 S.Giovanni Teatino
Chieti
ITALY3
Little Mark III
22-Jan-2009 17:47:04
Sheet2.Sch
Title
Size: Number:
Date:
File:
Revision:
Sheet of
Time:
B
R46
47K
C32
33p
R45
47K
C31
47n
R61
15K
C64
15n
R62
15K
R48
47K
C38
47p
R47
47K
C35
6.8n
R50
47K
C42
33n
C41
33n
R58
2.2k
R49
47K
R60
15k
C37
6.8n
C36
6.8n
R57
2.2K
V1
-V1
R52
47K
C34
33p
IN-EQL
LEVEL5
1
2
3
P3
MID_L 1
2
3
P4
MID_H 1
2
3
P5
LOW
1
2
3
P6
HIGH
LEVEL5
C63
3.3n
C66
2.2n
R51
47K
C65
470p
R75
68K
OUT-POST OUT-POST
C33
33p
R64
15K
C76
22n
C72
4.7n
R81
100K
1
2
3
P9
VPF
C77
R78
27K
R76
68K
R77
27K
C71
4.7n
R63
15K
R72
100
R67
220
C4410n
R68
220
R69
47k
C43
10n
1
2
3
P8A
VLE
4
5
6
P8B VLE
R65
220
R70
4.7
R71
4.7
C47
100u
C48
100u
C49
0.1u
C55
0.1u
C50
0.1u
C57
0.1u
V+15
V-15
V1
-V1
C51
0.1u
C58
0.1u
C52
0.1u
C59
0.1u
C53
0.1u
C60
0.1u
C54
0.1u
C61
0.1u
C69
100uF 35V
C70
100uF 35V
C56
0.1u
C62
0.1u
R80
1.5K
1 2
D14
ON
V-15
V+15
1
2_8
LEVEL4
1
2_14
1
4_1
R79
100
1
4_7
1
+V1
1
-V1
1
4_8
1
TP5
GND
1
TP6
GND
1
TP3
GND
1
TP4
GND
1
TP1
GND
1
TP2
GND
C4510n
C39
1uF
C67 10u
C40
1uF
8
9
10
IC2C
12
13
14
IC2D
1
4
2
3
11
IC4A
5
6
7
IC4B
8
9
10
IC4C

1 2 3 4 5 6
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C
D
6
54321
D
C
B
A
1
Parsek s.r.l.
via Aterno, 30
66020 S.Giovanni Teatino
Chieti
ITALY3
Little Mark III
22-Jan-2009 17:47:05
Sheet1.Sch
Title
Size: Number:
Date:
File:
Revision:
Sheet of
Time:
B
R6
18K
V1
-V1
R2
1M
CN1 R16
2.2K
C5
100p
1
2
3
P1 47K LOG
R7
33K
C1
47n
C3
100p
R35
2.2K
R8
22K
R15
22K
LEVEL1
R9
22K
C4
100p
R1
1M
R14
22K
C8
0.1u
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
CN3
SEND-EFF
RETURN
S-MIX(+)
S-MIX(-)
TUNER
OUT-POST
IN-EQL
IN-DIRECT
OUT-POST
1 2 3
CN5
C7
4.7u
D1
9.1V 1/4W
R5 470
D2
9.1V 1/4W
R32
56K
C12 47p
R33
56K
R22
22K
V1
-V1
R21
33K
C10
0.47u
RETURN
IN-EQL
LEVEL3
1 2
CN2
IN-EQL
R20
18K
C24
0,47u
C23
0,47u
R18
18K
Sub
R34
100
LEVEL2
R23
22K
R36
3.3K
SEND-EFF
TUNER
C9
0.1u
R37
10K
C11
0.33u
R17
4.7K
C25
10u
D7
D6
D10
LEVEL1
LEVEL3
D5
LEVEL2
R38
10K
R43
1.5K
C30
0.1u
R29
22K
V+15
1 2
D13
LED
D12
6.2V 1/4W
D9
OUT-POST
LEVEL4
1
2 3
T2
BC846
D11
LEVEL5
1
1_1
1
1_8
1
1_14
1
2_1
1
Tuner
1
Send
1
2_7
1
T1
1
Return
1
Input
R19
18K
C18
1u
D3
12V
D4
12V
C2
330p
C13
47n
C14
47n
C15
47n
R44
330
1
32
T3
2N7002
R4
1M
C22
1u
D8
C21
1u
R3
1M
V+15
V+15
R12
100K
R13
100K
C6
33p
R10
100K
R11
100K
1
2
3
4
CN4
C16
1u
C17
1u
1
4
2
3
11
IC1A
5
6
7
IC1B
8
9
10
IC1C
12
13
14
IC1D
5
6
7
IC2B
1
4
2
3
11
IC2A
R28
22K
R25
22K
R27
22K
R30
22K
R31
22K
R24
22K
R26
22K
R40
1K
R39
1K
C27
33p
C26
33p
1
2
3
P2
LINE_OUT
S-MIX(+)
S-MIX(-)
C20
1u
R41
1M
C19
1u
R42
1M
1
MIX(+)
1
MIX(-)
C28
33uF 63V
C29
33uF 63V
V1
-V1
3
2
1
8 4
IC3A
TL072
5
6
7
IC3B
TL072

1 2 3 4 5 6
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C
D
6
54321
D
C
B
A
3
Parsek s.r.l.
via Aterno, 30
66020 S.Giovanni Teatino
Chieti
ITALY3
Little Mark III
22-Jan-2009 17:47:05
Sheet3.Sch
Title
Size: Number:
Date:
File:
Revision:
Sheet of
Time:
B
C68
10u
C46
10n
C73
4.7n
R87
8.2K
R88
8.2K
1 2
3
T4 J112
-V1
1
2
5
4
IC6
H1AA1
R56
47K
R90
820K C78
2.2u
R92
820K
C79
1u
R91
820K
R59
2.2K
R93
120
R86
1K
R66
220
R55
47K
C81
47p
C74
1n
C75
1n
R89
22k
R94
47K
R84
10K
R95
6.8K
R85
10K
C82
220p
R82
4.7K
R74
100
1
2
3
CN6
Bib
Mono
1 2 3
CN7
Bib
Mono
1
2
3
P7
POT1-S
1 2 3 4
CNP7
MASTER
Output
1
5_1
1
5_7
1
5_14
1
5_8
R83
3.3K
D15
D16
12
13
14
IC4D
V1
-V1
1
4
2
3
11
IC5A
5
6
7
IC5B
8
9
10
IC5C
12
13
14
IC5D
OUT-POST OUT-POST
1
2
3
4
5
6
7
8
9
10
CN8
+
V+15
V-15
V+22
R54
47K
C80
47pF
1
4_14
R53
47K R73
100