Logitek
MON-10
Meter Monitor
& Switcher
Operation & Service Manual
MON-10
INSTRUCTION MANUAL
Table of Contents
SECTION 1 — GENERAL INFORMATION
1-1 General Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1-2 Physical Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1-3 Electrical Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1-4 Instrument Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1-5 Where to find help . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
SECTION 2 — PREPARATION FOR USE
2-1 Initial Inspection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2-2 Claims . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2-3 Repacking for Shipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2-4 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2-5 Connecting Inputs and Outputs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
SECTION 3 — OPERATING INSTRUCTIONS
3-1 Input Selector Pushbuttons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3-2 SOURCE Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3-3 METER Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3-4 VOLUME Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
SECTION 4 — PRINCIPLES OF OPERATION
4-1 General Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4-2 Fuse. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4-3 Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4-4 Switching and Amplification Circuitry. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
SECTION 5 — REPLACEMENT PARTS LIST
5-1 MON-10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
SECTION 6 — MANUFACTURERS LIST
SECTION 7 — DIAGRAMS
Page i
** MON-10 Instruction Manual **
SECTION 1 — GENERAL INFORMATION
1-1 General Description
and serial number appear on a label on the back of the
unit near the power cord. All correspondence to your
Logitek dealer or to the Logitek factory should refer to
the model number and serial number.
The Logitek MON-10 is a mechanical routing
switcher, a six-range VU meter and a six-watt amplifier
all in one convenient rack-mounted unit.
1-5 Where to find help
The MON-10 features ten balanced stereo inputs,
any one of which can be selected using front-panel
pushbuttons. The selected input is passively fed to
balanced output terminals on the rear panel. It is also
buffered and fed to a four-position source mode
switch. This switch selects whether the meter and
monitor will be fed the left channel, the right channel,
the mono sum (L+R) or the out-of-phase difference
(L-R).
Logitek customer service personnel are available
to help with any questions, comments or problems you
might have with the MON-10, both during and after the
warranty period. Our hours of operation are 8AM to
5PM central time. We may be contacted in one of the
following ways:
By Phone: 877-231-5870 (U.S.A. & Canada)
or 713-664-4470
The output of the source mode switch feeds a meter
amp, which in turn feeds a built-in VU meter and peak
LED. The VU meter can be switched between any of
six ranges, as determined by the front panel meter
switch. The mode switch also feeds a six-watt monitor
amp, which in turn feeds either a built-in speaker,
headphones, or an external speaker.
By Fax:
713-664-4479
By Email:
By Mail: Logitek Electronic Systems, Inc.
5622 Edgemoor Drive
Houston, TX 77081
1-2 Physical Description
USA
The Logitek MON-10 is constructed within a 3 1/2"
H x 19" W X 7" D cabinet, which is designed to take up
two rack spaces in a standard 19" equipment rack.
The power cord, fuse and all connections except the
headphone jack are located on the rear panel. The
headphone jack, meter, speaker and all controls are
located on the unit’s front panel.
1-3 Electrical Specifications
Number of Inputs:
10 stereo
Input Level:
normal
maximum
0 dBu
+23 dBu
Input Impedance:
140kohms
Line Output Level:
Line output switching is passive so the output
level, impedance and balancing is the same as
that of the selected input.
Speaker Output Level:
maximum
Speaker Output Noise:
6 watts
60 dBu
ref. 0 dBu input
AC Line Input Voltage:
50-60 hz
105-129 V
(optional factory modification for 220-240 VAC)
1-4 Instrument Identification
The MON-10 is identified by a model number and a
three or four digit serial number. The model number
** MON-10 Instruction Manual **
Page 2
SECTION 2 — PREPARATION FOR USE
2-1 Initial Inspection
Unbalanced equipment can be fed from the output
of the MON-10 by connecting the “+” terminal on the
MON-10 to the “hot” input on the unbalanced equip-
ment, while leaving the “-”terminal on the MON-10 un-
connected. Connect the cable shield to the ground
side of the input connector on the unbalanced unit.
When feeding unbalanced equipment from the output
of the MON-10, it is important that the “-” output termi-
nal be left unconnected. Connecting this terminal to
ground will not harm the equipment. However, it might
cause undesired crosstalk.
Check the shipping carton carefully for external
damage. If the carton shows evidence of abuse, ask
the carrier’s agent to be present when the unit is un-
packed. Carefully unpack the unit to avoid damaging
the equipment through the use of careless proce-
dures.Inspect all equipment for damages immediately
after unpacking. Bent and broken parts, dents, and
scratches should be noted.If damage is found, refer to
paragraph 2-2 for recommended claim procedures.
Keep all packing material for possible future use.
Care should be taken to be sure that cable shields
are connected to grounded equipment on only one
end of the cable. On any cable which connects two
pieces of equipment, of which both are grounded, the
cable shield must be left unconnected on one end, or
poor noise performance may result.
2-2 Claims
If the unit has been damaged, notify the carrier im-
mediately. File a claim with the carrier and advise
Logitek of such action to arrange for repair or replace-
ment without waiting for a claim to be settled with the
carrier.
An external speaker may be connected to the
SPEAKER OUT terminals on the rear panel. For best
performance, be sure that the speaker ground return
is connected to the indicated ground terminals on the
unit. To use the speaker on the front panel, connect
the SPEAKER OUT terminal to the INTERNAL
SPEAKER terminal. DO NOT CONNECT BOTH AN
EXTERNAL SPEAKER AND THE INTERNAL
SPEAKER AT THE SAME TIME, AS THE AM-
PLIFIER MAY BE DAMAGED IF YOU DO.
2-3 Repacking for Shipment
If the unit must be returned to Logitek, attach a let-
ter to it showing the owner’s name and address. A de-
scription of necessary service should be included in
the letter. The original shipping carton and packaging
materials should be used for reshipment if possible.
Use FRAGILE labels on each surface. Return the unit
freight prepaid. Be sure to insure the unit for its full
value. The unit will be repaired promptly and returned
freight prepaid.
2-4 Installation
The MON-10 is designed to be mounted in a stan-
dard 19" equipment rack by using the four mounting
holes in the corners of the front panel. While
flow-through ventilation is not necessary, the unit
should not be mounted directly above equipment
which produces significant heat, such as equipment
using vacuum tubes. The unit should never be oper-
ated if the ambient temperature is above 55 degrees C
(131 degrees F).
2-5 Connecting Inputs and Outputs
All inputs and outputs (except the headphone out-
put) are connected via the barrier strips on the rear
panel. These terminals are “wire-capturing”, so it is
not necessary to attach crimp lugs to each wire before
fastening the wire to the terminal. Crimp lugs may be
used, however, if desired.
Balanced line-level inputs and the line output
should be connected the to terminals as indicated on
the rear panel. Unbalanced sources can be fed to the
MON-10 by connecting the “hot” lead from the unbal-
anced source to the “+” input terminal on the MON-10,
while connecting the “-”terminal on the MON-10 to the
accompanying MON-10 ground terminal.
Page 3
** MON-10 Instruction Manual **
SECTION 3 — OPERATING INSTRUCTIONS
3-1 Input Selector Pushbuttons
The meter, monitor, and output terminals can be fed
from any one of ten different stereo inputs.The input is
selected by depressing any of the ten pushbuttons on
the front panel. Inputs may be labeled using the re-
movable label strip under the pushbuttons.
3-2 SOURCE Switch
The SOURCE switch determines the mode of the
signal fed to the meter and monitor, but DOES NOT af-
fect the line output signal. From the stereo input se-
lected on the input selector pushbuttons, the
SOURCE switch selects the left channel, the right
channel, the mono sum (L+R) or the out-of-phase dif-
ference (L-R) signal to feed to the meter and monitor,
allowing a visual and aural evaluation of channel bal-
ance and source phasing.
3-3 METER Switch
The METER switch determines the 100% VU level
of the meter. By selecting any of the six positions, the
user can measure audio levels over a wide range. The
METER switch DOES NOT affect the line output or the
speaker and headphone level.
3-4 VOLUME Control
This control sets the level fed to the internal
speaker, the external speaker and the headphone
jack. It DOES NOT affect line output signal or the me-
ter.
** MON-10 Instruction Manual **
Page 4
SECTION 4 — PRINCIPLES OF OPERATION
4-1 General Information
“R”and “L+R”position on switch S12b and the “R’posi-
tion on S12a. The right channel signal is also inverted
by IC3b and fed to the ”L-R" position on switch S12b.
The MON-10 is designed to need a minimum of
maintenance for long trouble-free operation. Should
repair be necessary, the technician should first read
the information in the manual concerning the circuits
in question, and should follow proper procedures for
testing and replacing semiconductors. Logitek engi-
neers are readily available at the factory to provide
technical assistance both during and after the war-
ranty period.
The output of the SOURCE switch S12a is fed
through the VOLUME pot R38a and buffer amp IC6 to
the J6 HEADPHONE jack tip contact. Likewise, the
output of S12b is fed through VOLUME pot R38b and
buffer amp IC5 to the J6 HEADPHONE jack ring con-
tact. The output of the J6 tip ring switching contacts
are combined by R44 and R45 to form a mono sum
and fed through power amp IC9 to the rear panel AMP
OUT terminal. This terminal may be connected to an
external speaker, or it may be connected to the IN-
TERNAL SPEAKER terminal so that the speaker on
the front panel is active.
4-2 Fuse
The primary winding of the power transformer is
fused with a 1/2 amp slow-blow type 20mm fuse,
housed in a fuse holder on the rear panel of the unit. It
should only by replaced with fuses of the same type
and current rating.
The output of S12a and S12b are also combined to
a mono sum by R32 and R33 and fed to op-amp IC4b,
which amplifies the signal and feeds it though the me-
ter trim control R32 to the front-panel VU meter. The
gain of IC4a, and thus the calibration of the meter, is
set by the resistor selected by the METER switch, S11.
The meter may be more precisely trimmed by adjust-
ing R30 for the desired reading.
* * * * * * * IMPORTANT NOTE * * * * * * *
Do NOT replace fuses without first disconnecting
the amplifier’s power cord from the wall socket, as
dangerous voltages are present which may cause
electrical shock. Always use fuses of the same value
and type as specified in this manual. Do NOT use
fuses of a higher value than those specified, as shock
hazard and fire hazard may result.
The output of IC4b also feeds D3, which rectifies
the signal and feeds holding capacitor C9, decay time
resistor R28, and op-amp IC4a . IC4a works as a com-
parator, comparing the rectified audio signal of the
peak adjust control, R29. When the audio signal ex-
ceeds the threshold determined by the setting of R29,
IC4a supplies current to turn on the peak led, D1.
* * * * * * * * * * * * * * * * * * * * * * * * * * *
A blown fuse is most often, although not always, a
symptom of another failure. Related circuitry should
always be carefully examined after any fuse failure,
especially if a replacement fuse also blows.
4-3 Power Supply
Each MON-10 contains a well-regulated power
supply to create necessary operation voltages.
T1 is a center-tapped step-down power transformer
which is loaded with a full-wave bridge rectifier, RT1.
The DC outputs of RT1 are filtered by capacitors C11
and C12 and fed to two voltage regulators, IC8 and
IC7. These regulators provide positive and negative
18 volt outputs which feed the unit’s amplifier stages.
4-4 Switching and Amplification Circuitry
Input signals to the MON-10 are selected by the in-
put selector pushbuttons S1-S10 and fed directly to
the LINE OUT terminals on the unit’s rear panel. The
left channel of the selected input signal is also fed to
IC1b, which isolate the signal and convert it to a sin-
gle-ended source. The right channel of the selected
input signal is similarly fed to IC2a and IC2b, which do
the same as IC1a and IC1b.
The single-ended left channel output from IC1b is
fed to the “L”, “L+R”and “L-R”position on the SOURCE
switch, S12a and the “L” position on S12b. The sin-
gle-ended right channel output from IC12b is fed to the
Page 5
** MON-10 Instruction Manual **
SECTION 5 — REPLACEMENT PARTS LIST
All replacement parts are stocked in depth at the Logitek factory. Most are also available through local electronic parts
distributors. For your convenience in purchasing replacement parts locally, we include the following parts list.
All Logitek part numbers consist of a two letter manufacturer code followed by that manufacturer’s standard part num-
ber for the item. A List of manufacturers, arranged alphabetically by manufacturer code, follows this parts list in Section 7.
All resistors are 1/4 watt, +/- 5% tolerance unless otherwise noted.
SYMBOL
5-1 MON-10
DESCRIPTION
LOGITEK PART NUMBER
Capacitors
C1-4
C9
47uf/10V non-polar electrolutic
.01uf/16V ceramic
NI-UES1A470MPJ
CE-UK16-103
C10
C11
C12,13
C14-18
C19
15uf/20V tantalum
SL-TAP156K020CCS
SL-TAP224K050HSB
IL-108TTA035M
SL-TAP106K025HSB
IL-33MSS063K
.22uf/50V tantalum
1000uf/35V electrolytic
10uf/25V tantalum
.33/50V polyester film
1uf/35V tantalum
C20
SL-TAP105KO35HSB
Diodes
D1
Red LED
IE-LL203R
D2,3
D4,5
D6
D7,8
D9
Small signal diode
1A signal diode
6.3V zener 1W
1A signal diode
6.3V zener 1W
MO-1N4148
MO-1N4001
MO-1N4735
MO-1N4001
MO-1N4735
Fuses
F1
1/2 amp slow blow, 20mm
LF-239.250
Integrated Circuits
IC1-4
IC5,6
IC7
IC8
IC9
6 pc.
1 pc.
2 pc.
1 pc.
Dual bi-fet op-amp
Dual Quiet op-amp
-18 volt regulator
+18 volt regulator
Power op-amp
8-pin dip socket
Heat sink - pc mount
Heat sink - clip
TI-TLO72CP
SG-NE5532N
TI-uA7918CKC
TI-uA7818CKC
NA-LM1875T
EM-100-083-10-1005
AA-5632B
TM-6045B
BQ-K4-54-AC
TO-220 insulator
Connectors
J1
6-pin large dip socket
6-pin socket
3-pin socket
Headphone jack
40-pin socket
3-pin socket
6-pin header large
6-pin header
3-pin header
40-pin header
3-pin header
Power entry module
PN-CE156F20-6A
PN-CE100F28-6A
PN-CE100F28-3A
SW-RN114BPC
PN-050-040-455
PN-CE100F28-3A
PN-MFSS156-6A
PN-MFSS100-6A
PN-MFSS100-3A
PN-051-040-153
PN-MFSS100-3A
SR-6200.4115
J2,3
J4,5
J6
J7,10
J11
P1
P2,3
P4,5
P7,10
P11
P14
Meter
M1
1 pc.
1 pc.
2 1/2" VU meter
2 1/2" light box
Light bulb
SO-AL29R, B-SCALE
SO-29/LIGHT BOX-12VDC
CM-382
** MON-10 Instruction Manual **
Page 6
SYMBOL
R1-4
R5-8
R9-12
R13-16
R17
R18
R19
R20
R21
DESCRIPTION
Resistors
LOGITEK PART NUMBER
69.8K, 1%
4220, 1%
69.8K, 1%
4220, 1%
6810, 1%
1540, 1%
909, 1%
562, 1%
174, 1%
53.6, 1%
5100
R22
R23,24
R25
560
R26
R27
11.5K, 1%
5100
R28
R29
R30
R31
1M
5000 peak trim
10K meter trim
1000
BN-3386P-1-502
BN-3386P-1-103
R32,33
R34,
R35
R36,37
R38a,b
R39
20K
1000
10K
10
10K ohm VOLUME pot
1000
CL-70W1N04S103A
R40
R41,42
R43
10K
10
1000
R44,45
R46
R47
10K
1000
1.2
R48
R49
10K
150
1 pc.
1 pc.
Knob
Cap with line
SO-S211-250BLACK
SO-C211BLACK
Rectifiers
RT1
1A bridge
GI-DF10M
Switches
S(1-10)
S11
S12
10 pc.
2 pc.
2 pc.
Input selector
Meter selector
Source selector
Pushbutton cap
Knob
EC-10XTA15(NONE)4UGRA
GR-71BDF30-01-1-AJN
GR-71BDF30-02-1-AJN
SH-FA20108010112
SO-S211-250BLACK
SO-C211BLACK
Cap with line
Speakers
SP1
Speaker
IC-S300SA
Transformers
T1
36v 1A
36V 1.2A 220V primary
ST-P8671
SI-A41-43-36
T1 (220V version)
Terminals
4 pc.
Terminal blocks
Label strip
Label strip holder
Label strip window
Power cord
RD-3PCV-15
AD-4-15230-0030
AD-4-25357-0020
AD-4-25358-0140
BE-17251
Selector card
Terminal card
Amp card
LG-131B
LG-132A
LG-133D
Page 7
** MON-10 Instruction Manual **
SECTION 6 — MANUFACTURERS LIST
CODE
MANUFACTURER
LOCATION
AA
AD
BE
BN
BQ
CE
CL
CM
EC
EM
GI
GR
IC
IE
IL
LF
LG
MO
NA
PN
RD
SG
SH
SI
SL
SO
SR
ST
SW
TI
Aavid Engineering
ADC
Belden Wire and Cable
Bourns, Inc.
Bergquist Co.
Centralab Electronics Div.
Clarostat Mfg. Co., Inc.
Chicago Miniature Lamp, Inc.
Electronic Components Groupe
Ecam Technology
General Instruments/Quality Technologies
Grayhill Inc.
Intervox (International Components Corp)
Industrial Electronics Engineers
Illinois Capacitor
Laconia, NH
Minneapolis, MN
Richmond, IN
Ogden, UT
Minneapolis, MN
Milwaukee, WI
Dover, NH
Buffalo Grove, IL
Minneapolis, MN
Scottsdale, AZ
Sunnyvale, CA
LaGrange, IL
Melville, NY
Van Nuys, CA
Lincolnwood, IL
Des Plaines, IL
Houston, TX
Littlefuse, Inc.
Logitek (Circuit cards)
Motorola Semiconductor Products
National Semiconductor
Panduit Corp.
Reed Devices, Inc.
Signetics Corporation
ITT Schadow, Inc.
Signal Transformer
AVX/Stantel Corp.
Selco Products
Schurter, Inc.
Stancor Products
Phoenix, AZ
Santa Clara, CA
Tinsley Park, IL
Carol Stream, IL
Sunnyvale, CA
Eden Prairie, MN
Inwood, NY
Myrtle Beach, SC
Buena Vista, CA
Petaluma, CA
Logansport, IN
Chicago, IL
Switchcraft Inc.
Texas Instruments, Inc.
Thermalloy, Inc.
Dallas, TX
Dallas, TX
TM
** MON-10 Instruction Manual **
Page 8
SECTION 7 — DIAGRAMS
Page 9
** MON-10 Instruction Manual **
** MON-10 Instruction Manual **
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