OTS AQUACOM MK-III User manual

Aquacom
mk-III
3-diver intercom
Full-Duplex Surface Station for
Underwater Communications
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“Technology In Depth” ®

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506279-000 REV. A
- NOTICE -
This manual and the information contained herein are provided for use as a main-
tenance and operation guide. No license or rights to manufacture, produce, and/
or sell either the manual or articles described herein are given. Undersea Systems
International, Inc., dba Ocean Technology Systems, reserves the right to change
specications without notice. We recommend that all users read and fully understand
this manual before using the Aquacom®MK-III 3-Diver Intercom.
All statements, technical information, and recommendations herein are based on
tests we believe to be reliable, but the accuracy or completeness thereof is not guar-
anteed; and the following is made in lieu of all warranties, expressed or implied,
including the implied warranties of merchantability and tness for purpose: Seller’s
and Manufacturer’s only obligation shall be to replace such quantity of the product
proved to be defective. Before using, the user shall determine the suitability of the
product for intended use, and the user assumes all risk and liability whatsoever in
connection therewith. Neither Seller nor Manufacturer shall be liable either in tort
or in contract for any loss or damage—direct, incidental, or consequential—arising
from the use of or the inability to use the product. No statement or recommenda-
tion not contained herein shall have any force or effect unless it is in an agreement
signed by ofcers of the Seller and Manufacturer.
- IMPORTANT SAFETY NOTICE -
(Please read before using product.)
It is absolutely essential that all operators are properly trained and equipped
and fully understand this user’s manual before attempting to use the MK-III
3-Diver Intercom.
While the MK-III 3-Diver Intercom provides good underwater communica-
tions, it does not change or eliminate the potential hazards of diving!
Copyright © 2019 by Undersea Systems International, Inc., dba
Ocean Technology Systems. All rights reserved.
Specications subject to change without prior notice.
Refer to the Library page of our Web site, www.otscomm.com, for a list of
any changes made to this manual since its publication.

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506279-000 REV. A
Table of Contents:
Section 1: Introduction ................................................................................4
Section 2: Description of Equipment..........................................................5
2.1 Specications ...................................................................................5
2.2 Included With MK-III ......................................................................6
2.3 Additional Components ...................................................................6
2.3.1 Communications Cables....................................................6
2.3.1.1 CommRopes ......................................................6
2.3.1.2 Floating Commcable .........................................6
2.3.2 Earphone-Microphone (EM) Assemblies ..........................6
2.3.3 Umbilical Adapters............................................................6
2.3.4 THB-MK-III Headset ........................................................7
2.36 HHM-2 Microphone..........................................................7
2.4 MK-III Panel Map............................................................................7
2.5 MK-III Case Map.............................................................................8
Section 3: Supplying Electrical Power........................................................9
3.1 Internal Battery ................................................................................9
3.1.1 Battery Charging..............................................................10
3.1.2 Battery Replacement .......................................................11
3.2 AC Power.......................................................................................12
3.3 External DC Power ........................................................................12
Section 4: Operation ................................................................................. 13
4.1 Controls and Adjustments..............................................................13
4.1.1 System Settings...............................................................13
4.1.2 Topside Controls.............................................................14
4.1.3 Diver Controls ................................................................16
4.2 Daisy Chaining...............................................................................16
4.3 After the Dive ................................................................................16
4.4 Helpful Hints..................................................................................17
Section 5: Maintenance And Sub-Panel replacement ........................... 18
5.1 Preventive Maintenance.................................................................18
5.2 Sub-Panel Replacement .................................................................18
5.3 Troubleshooting .............................................................................20
5.4 Spare Parts .....................................................................................21
Limited Warranty ......................................................................................24
Table of Figures:
Figure 1: Panel Map.....................................................................................7
Figure 2: Case Map ......................................................................................8
Figure 3: Accessory Net ...............................................................................9
Figure 4: Battery Replacement .................................................................11
Figure 5&6: Two and Four Wire Conguration......................................13

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506279-000 REV. A
SECTION 1
Introduction
In this manual, you will nd all of the information you will need to know
regarding the Aquacom MK-III 3-Diver Intercom system. Start with Sec-
tion 2 which contains a list of specications and information about MK-III
hardware. Once you’ve read this section, please read the operation instruc-
tions contained in section 4. These sections will instruct you in the vital
functions of the MK-III 3-Diver Intercom.
Before operating the MK-III 3-Diver Intercom, read this entire manual. In
addition to the information presented on functions and operation, there are
some important safety issues all users must be familiar with before using
the MK-III. If you have any questions, contact your local OTS dealer, or
feel free to contact OTS directly (See page 20 for OTS contact informa-
tion.)

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506279-000 REV. A
SECTION 2
EQUIPMENT DESCRIPTION
2.1 SPECIFICATIONS
Input Voltage:
Idle Current:
Audio Frequency:
Battery Type:
Battery Life:
Operating Temperature:
Storage Temperature:
Cabinet Material:
Front-Panel Material:
Housing Dimensions(HxWxD):
Weight:
Latches:
Case:
12VDC (Minimum 3 amps) or 90–240 V AC, 50–60 Hz
300 mA
300-4000 Hz
Nonspillable Lead Acid, 12v, 7.2Ah
20 hours idle, 12 hours Working
-40°C to 50°C (-40°F to 122°F)
-40°C to 40°C (-40°F to 104°F)
Molded ABS
Stainless Steel
10-3/4in x 16-3/4in x 8-3/4in
19.5 lbs (8.84kg)
Stainless Steel
Designed to meet IP65

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506279-000 REV. A
2.2 INCLUDED WITH THE MKIII
e following items are provided with the MK-III:
• RCS-20US battery charger
• RB-12 rechargeable battery
2.3 ADDITIONAL COMPONENTS, SOLD SEPARATED
All additional components can be sourced from OTS or your local OTS
dealer.
2.3.1 COMMUNICATIONS CABLES
Each diver requires an intercom cable to connect to the MK-III. Be sure
to obtain cables that mate with the Diver Earphone-Microphone Assem-
bly and the corresponding MK-III mating connectors. e MK-III panel
mounted Diver Earphone-Microphone connectors are available in Banana,
Amp, and 5-pin MS styles.
2.3.1.1 COMMROPES
OTS oers CommRopes consisting of communication cables bundled in-
side a durable yet exible rope for connecting Ear/Microphone assemblies
to the MK-III.
2.3.1.1 FLOATING COMMCABLE
Floating Communications Cables were made with Public Safety and
Aquarium divers in mind. is buoyant cable helps minimize entangle-
ment hazards by keeping the bulk of the cable on the surface.
2.3.2 EARPHONE-MICROPHONE (EM) ASSEMBLIES
Each diver will require an Earphone-Microphone Assembly in order to
communicate. OTS oers a wide range of options and styles to match
your Full Face Mask. e MK-III supports the use of pre-amplied micro-
phones, which tend to be more durable, rugged and require less mainte-
nance than dynamic(unpowered) microphones—although they oen have
lower delity, range, and speech intelligibility.
2.3.3 UMBILICAL ADAPTERS
OTS oers adapters to interface to your current umbilical/communica-
tions cables and the intercom cable that you’ve chosen to use.

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506279-000 REV. A
1. Diver and Tender Microphone Controls: ese knobs control the
microphone volumes from each diver and for the tender.
2. Diver Earphone Volume Controls/PTT: ese knobs control the out-
put volume to each diver and to the Tender, and can be depressed to
control the Push-To-Talk functions.
3. Diver Umbilical Receptacles: Connects Diver intercom cables to the
MK-III. is sub-panel is available in Amp and a 5 pin MS connec-
tor version. e banana connectors can be used with bare wire, in the
event that your earphone-microphone cables do not have a mating
connector.
4. Topside Volume And Panel Speaker Control on/o: Controls the
diver unit speaker volume
5. Aux Jack: An 8mm audio jack that can be used to connect accessories
and to play external audio from another device.
Fig. 1
2.3.4 THB-MK-III HEADSET (900465-000)
OTS oers an optional tender headset designed to support all MK-III fea-
tures, including a headset mounted Push-to-talk button.
2.3.5 HHM-2 MICROPHONE (910193-000)
OTS oers an optional hand-held microphone designed to support all
MK-III features.
2.4 MKIII PANEL MAP
Figure 1 depicts the MK-III panel. Use the numbered key to familiarize
yourself with the locations and functions of each control before attempting
to dive with the MK-III Intercom.

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506279-000 REV. A
6. Panel Microphone: e panel mounted Microphone.
7. Diver Pre-amp: Powered Mic on/o switch with LED.
8. Panel Mounted Speaker: e panel mounted speaker.
9. Push to Talk: e push to talk button toggles the panel mounted mi-
crophone.
10. REM: Remote Tender Headset PTT connection.
11. Line In: e Line In input allows for external audio playback to the
divers, such as a music or another MK-III.
12. Remote Speaker: Remote speaker receptacles. Can be used to connect
a two-pin unpowered speaker.
13. Line Out: e Line Out input can be used to connect recording equip-
ment, allowing recording at the line level, but not at the speaker level.
And to connect another MK-III.
14. 12 Volts Power/CHG: e connector for an external 12VDC power
supply and for charging the battery.
15. Battery Level: Indicator for the charge level of the battery.
16. Power: e power indicator. is light indicates if the unit is powered
on.
17. Power Switch: A two position toggle switch for turning on and o the
power to the MK-III
2.5 MKIII CASE MAP
Fig. 2
1. Case Latches: e stainless-steel latches on either side of the case are
used to close and seal the MK-III case.

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506279-000 REV. A
When the latches are closed and the unit is sealed, the MK-III is pro-
tected from ocean spray. While the MK-III has been tested against an
overboard scenario, it is not guaranteed to be protected against full
submersion.
2. Bumper Feet: e MK-III has an additional set of Bumper Feet, al-
lowing the unit to be used from either a face up (vertical) or face out/
horizontal orientation. e face out (horizontal) orientation is espe-
cially useful when utilized on a work station or in rain or spray condi-
tions to prevent water from accumulating on the panel.
3. Lid hinges: e hinges on the back of the unit are designed to allow
the lid to be removed from the unit. While the lid is removed, the
unit can be operated while rotated 90°.
4. Safety Vents: e Safety vents can be opened by rotating counter-
clockwise. ese vents must be opened if the MK-III is transported
by air, or when the unit is charging.
5. Accessory Net: Inside the lid hangs the Accessory Net. (See g 3.)
Elastic loops mount the net to hooks built into the lid. e net can be
used to store MK-III accessories, such as the AC charger. If stowing
a headset, ensure that it is not pressing against the umbilical binding
posts when the lid is closed.
SECTION 3
SUPPLYING ELECTRICAL POWER
e MK-III 3-Diver Intercom provides three options for supplying power:
the internal Battery, 90-240 Volts AC, or a 12-Volt DC external power sup-
ply. e best option for you will depend on your application prole.
3.1 Internal Battery, RB-12, Non-spillable
Inside the MK-III is a lead-acid battery, which supplies 12 volts at
7.2amp-hours. Once the battery has reached less than 11.4Vdc, e unit
will shut o aer 1 minute of the LED blinking red. e power shut o
occurs to prevent sudden battery malfunction or shortened battery life.
Fig. 3

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506279-000 REV. A
DANGER
WHILE RECHARGING THE BATTERY AND THE SAFETY
VENTS ARE OPEN, THE UNIT MUST BE KEPT AWAY
FROM WATER AND OCEAN SPRAY. FAILURE TO KEEP
THE UNIT FREE FROM WATER MAY CAUSE INJURY OR
DEATH
Charge Remaining LED Audio Tone
100% 3 Green No Tone
80% 2 Green No Tone
60% 1 Green No Tone
40% Ye l l o w 1 beep / 1minute
25% Red 2 beep / 30 second
At startup, if the LED is solid red, the battery is no longer holding a
charge and must be replaced.
3.1.1 BATTERY CHARGING
To charge the MK-III using AC power, connect the supplied charger/
maintainer AC power cable to the Charger/Maintainer input (Fig 1, #14).
Connect the Charger/Maintainer power plug to an AC power outlet that
supplies 90–240 volts at 50/60 Hz.
Safety Precautions:
While charging the battery it is very important to open the 2 safety vents.
Allow at least 20 minutes after charging for any gasses to dissipate before
returning the unit to its operating position and closing the ventilation valve
(by rotating fully clockwise to prevent water entry).
A fully depleted battery can be recharged completely in about 3–5 hours.
While the battery is being charged and its voltage is below maximum, the
charge indicator LED located on the RCS-20US will illuminate red in color.
When the battery has been completely recharged, the charger will enter
trickle-charge mode to maintain maximum battery voltage and the charger
LED will illuminate green.
LED BATTERY CONDITION INDICATOR

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506279-000 REV. A
Do not allow a battery to remain discharged for long periods of time. While
in storage or long periods of non-use, charge the battery at least every 60-90
days. Failure to maintain a charge on the battery will result in a failure to
take and maintain a charge.
Ensure that the RCS-20US is operated in a dry area and connected to
a GFI protected circuit.
3.1.2 BATTERY REPLACEMENT:
The battery should provide a long lifetime of service through many depletion
and recharging cycles. Nevertheless, eventually the battery may cease
maintaining an adequate charge; in this event you will have to replace the
battery. Replacement batteries (part no. 392016-000) are available from
OTS or your local dealer.
Follow these instructions to replace the battery:
1. Ensure the power switch (Fig. 1, #17) is toggled to the off position. If
the unit is connected to an external power source, unplug the power
cable from it.
2. Disconnect all devices attached to the front panel.
3. Using a Phillips screwdriver, remove and set aside the ten panel screws
and nylon washers.
4. Using the two handles, remove the front panel. The MK-III’s internal
hardware and electronics are attached to the panel, so care must be
taken when handling the panel.
5. Disconnect the battery wire connector on the PCB by pulling connector
away from the mating connector.
Fig. 4

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506279-000 REV. A
6. Remove and set aside the four hex nuts, washers, lock washers (#1,2,
and 3) and battery bracket (#4) that secures the battery to the base.
7. Lift the battery (#5) and turn it so that the terminals are facing upwards.
Remove the connectors from the terminals and lift the battery away
from the unit.
8. Replace the battery with the new one. The terminals should be oriented
upwards. Reconnect the battery connectors to battery, connecting the
red right angle connector to the + Terminal and connecting the straight
clear connector to the - Terminal.
9. Secure the battery with the bracket and hex nuts. Tighten the hex nuts
securely without overtightening.
10. Reconnect the battery wire harness to the PCB.
11. Reinstall the MK-III panel using the screws and washer previously
removed.
13. Reconnect all devices to the front panel.
3.2 AC POWER
To operate the MK-III using AC power, connect the supplied charger/
maintainer AC power cable to the Charger/Maintainer input (Fig 1, #14).
Connect the Charger/Maintainer power plug to an AC power outlet that
supplies 90–240 volts at 50/60 Hz.
Operation of the unit with AC power will supply charging current to the
battery. See Section 3.1.1 for safety precautions. While operating the unit
with AC power, you do not have to open the safety valves.
Note: The standard AC power cable has a plug compatible with the standard
electrical outlets used in the U.S.A. However, if you need a plug for a
different region of the world, appropriate power cords are available from
OTS or your OTS dealer.
3.3 EXTERNAL DC POWER
To operate the MK-III using an external 12-volt DC power source (such
as a lead-acid battery of 5.0 Ah or other DC power supply of at least 3A),
connect electrical cables via a mini double banana plug to the DC power
receptacle (Fig. 1, #14) on the MK-III front panel. Be sure to connect the
negative lead to the black socket and the positive to the red.
If the voltage of the external DC power source falls below that of the internal
battery, the MK-III will begin to draw current from both power sources.
Therefore, the battery level indicator (Fig. 1, #15) will monitor the voltage
of both the internal battery and the external DC source.

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506279-000 REV. A
SECTION 4
OPERATION
4.1 CONTROLS AND ADJUSTMENTS
4.1.1 System settings
System power: The MK-III’s system power switch is a 2-position toggle
that turns the unit on and off. Allow 2 seconds for the unit to fully power up.
Two-Wire or Four-Wire selection: Only for banana connector versions.
To select Two-wire transmit mode, plug the earphone banana connector
into the microphone banana connector. (See Fig. 5 on the next page) This
allows for a diver to transmit or receive, but never both at the same time.
To select Four-wire mode, plug the microphone connector into the
microphone jack and the earphone connector into the earphone jack. (See
Fig. 6) This will allow the divers to both listen and talk at the same time.
Two-Wire Operating Instructions: Note: Do not connect divers’ ear/
mic assembly in the two wire conguration if you intend to use the Diver
Pre-Amp option. Additionally, Pre-Amplied microphones cannot be used
in two wire mode. Do not engage the Pre-Amp option in two wire mode.
While in the Two-wire conguration, any diver can talk to the Tender, but
not to other divers. If the Tender wishes to talk to the divers, the Tender
must press the PTT button on either their headset or on the panel.
While the PTT button is depressed, the divers cannot communicate with
the Tender; they must wait until the Tender has let go of the PTT button.
In the case that the Tender wants a Diver to talk to the other Divers, the
Tender must depress the Earphone/PTT knob of the talking diver.
WHILE OPERATING THE MK-III, ENSURE THE DIVER’S MOUTH/LIPS
ARE NOT IN DIRECT CONTACT WITH THE MOUNTING SCREWS OF
THE MICROPHONE. FAILURE TO DO SO MAY CAUSE A MILD SHOCK
WHEN THE MK-III PUSH-TO-TALK (PTT) BUTTON IS PRESSED. TO
AVOID SHOCKING, DO NOT PLACE MOUTH/LIPS ON THE SCREWS OF
THE MICROPHONE AND/OR INSULATE THE SCREWS WITH A RUBBER
BO OT.
PLEASE CONTACT OTS IF YOU REQUIRE A RUBBER BOOT FOR YOUR
APPLICATION
WARNING

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506279-000 REV. A
Four-Wire Operation Instructions: While in the Four-Wire conguration,
the Tender and Divers can communicate freely without the need to press
any buttons.
Diver Pre-Amp: Do not connect non-powered earphone / microphone
assemblies when the pre-amp is activated. Doing so will damage the
earphone / microphone assembly. To turn on the Diver Microphone Pre-
Amplier, press and hold the Diver Pre-Amp button for 5 seconds. When
the Pre-Amp is activated, a blue ring light around the button will activate.
Turning on the Pre-Amplier is required if the divers are using powered
microphones. You cannot connect a combination of Powered and Unpowered
microphones while the Pre-Amplier is on. Doing so may cause damage
to an unpowered microphone.
4.1.2 TOPSIDE CONTROLS
Topside Mic Volume: Adjusts the volume of both the panel and headset
microphone.
Speaker Volume: Adjusts the volume of both the panel mounted speaker and
the headset earphones. Pressing on the knob will turn on and off the panel
mounted speaker and the connected LED, but not the headset earphones.
Push-To-Talk: WARNING: pressing the push-to-talk button could shock
the divers in the event that the diver microphone mounting screws are in
direct contact with the diver’s mouth. Ensure that the microphone is placed
away from the Diver’s mouth or the screws are insulated with a rubber boot.
Fig. 5 Fig. 6

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506279-000 REV. A
Pressing the PTT button will mute the panel speaker and activates the panel
microphone for as long as the button is depressed. Pressing the PTT button
also mutes all the diver microphones.
Panel Mic: The Panel Mic is normally deactivated. Pressing the PTT
button will activate the Microphone. The Panel Mic LED will conrm the
microphone is active. Communication should be clear as long as the Tender
is a foot or less away from the panel microphone.
REM Jack: When using the Remote jack, pressing the headset PTT button
mutes the panel mounted speaker, allowing the tender to more clearly hear
the divers. WARNING: pressing the push-to-talk button could shock the
divers in the event that the diver microphone mounting screws are in direct
contact with the diver’s mouth. Ensure that the microphone is placed away
from the Diver’s mouth or the screws are insulated with a rubber boot.
Topside headset Microphone and Earphone Jacks: Used to connect the
Tender earphone and/or microphone to the MK-III.
Line In: The line in jack allows the Tender to connect an RCA cable from
an external audio source to MK-III. It also allows “daisy chaining” MK-IIIs
and / or playing music from a player to the divers.
Line Out: The Line Out jack allows the Tender to connect an RCA cable
from the MK-III to an external device such as an audio recorder or for
“daisy chaining” MK-IIIs together.
AUX: The aux jack can be used to connect optional accessories and to
connect an audio player of your choice. The initial audio level of the player
must be set on the player itself, then can be adjusted for each diver by using
the MK-III’s panel controls.
4.1.3 DIVER CONTROLS
Diver Microphone Volume: Allows the tender to control the microphone
volume from each diver.

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506279-000 REV. A
Diver Earphone Volume: WARNING: pressing the push-to-talk button
could shock the divers in the event that the diver microphone mounting screws
are in direct contact with the diver’s mouth. Ensure that the microphone
is placed away from the Diver’s mouth or the screws are insulated with a
rubber boot. Allows the Tender to control the earphone volume of each
diver. Pressing down on the knob activates the PTT for that diver, which
mutes all the microphones of all the other divers. (But not the tender.)
Diver Earphone and Microphone Connectors: Used to connect diver
intercom cables to the MK-III. Diver earphone and microphone are available
in banana, 5-pin MS, and AMP connector congurations.
4.2 DAISY CHAINING
In the event that you have more than three divers, it’s possible to connect two
MK-III surface units together, allowing for up to six divers to communicate.
To connect two units together, connect an RCA cable from the Line In
connector from one unit to the Line Out connector to the second unit. Repeat
this process for the Line Out connector to the Line In connector.
4.3 AFTER THE DIVE
After each use, be sure to disconnect all connectors from the MK-III panel. If
you have been using the battery for power, recharge the battery for the next
use. Follow the preventive maintenance instructions presented in Section
5.1 to maintain your MK-III in optimal condition
If the MK-III is going to be transported airborne, OPEN BOTH SAFETY
VENTS TO DEPRESSURIZE THE UNIT’S INTERIOR DURING
FLIGHT. Failure to do so will cause the unit to seal shut. The valves are
located on the upper and lower halves of the case’s front with the panel facing
upward and are opened by fully rotating counterclockwise. Before using
the MK-III again, close the ventilation valves (by rotating fully clockwise)
to prevent water from entering the case.

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506279-000 REV. A
4.3 HELPFUL HINTS
These guidelines are provided to help you understand how best to use the
MK-III 3-Diver Intercom.
1. Before diving operations begin, check to ensure the microphone,
earphone, and wiring connections are secure and operating properly.
Ninety percent of all problems in underwater communications are due
to a connection problem.
2. If you will use battery power, always check the battery power level
before the dive, and recharge the battery if necessary.
3. Secure the MK-III if using it on a vessel that is rolling about. Strain-
relieve the umbilical(s) (diver intercom cables) so they will not pull
on the MK-III.
4. Ensure the umbilicals are dressed out so as not to trip anyone.
5. When talking to divers, keep in mind they have many things happen-
ing while underwater. It is best to get the diver’s attention before giv-
ing him a message (e.g., “Red Diver, Red Diver, this is Topside, come
in Red Diver”). The diver should then respond to inform you that he is
listening (e.g., “Topside, this is Red Diver, go ahead”).
6. Avoid excessive tender-to-diver volume. Most of the time, when there
is too much volume, the diver will hear distortion and ask for more
volume.
7. Speak slowly in one brief, continuous sentence. Speaking in short sen-
tences gives divers a chance to take a breath and still receive a clear
message.
8. When communicating with divers, it is a good idea to have the divers
repeat your messages to ensure they understood what you said. Also,
repeat what you heard the divers say to ensure everyone is communi-
cating accurately.
9. If this is the rst time anyone on your team is using underwater com-
munications, the team should get together to talk about the system.
Practice alternative communications in the event the communications
system fails to function.

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506279-000 REV. A
SECTION 5
MAINTENANCE AND SUBPANEL REPLACEMENT
5.1 PREVENTIVE MAINTENANCE
Although the Aquacom®MK-III 3-Diver Intercom has a rugged design,
it should be treated with care, as with any quality electronic equipment.
The following should be done regularly or before every dive to prevent
malfunction of the MK-III:
1. Clean the MK-III by wiping it free of dirt, debris, and water with a clean,
soft cloth. Warm water with a small amount of nonabrasive soap is the
recommended cleaning solution. Do not saturate the cloth or sponge;
doing so may allow water to ow inside the case and cause damage.
To clean the headset or optional hand-held microphone, use a mild soap
solution, and wipe it dry.
2. Examine the exterior of the MK-III to assure there is no damage.
3. Inspect the connectors and controls on the panel for signs of damage.
4. Check the connectors for bent or corroded pins.
5. Check the power cables for cuts and abrasions.
6. With the unit’s power on, test the indicator LEDs to ensure they illuminate
when they should.
7. Inspect the case gasket (underneath the panel) and the O-ring seal
between the case and lid to assure they are clean and show no signs of
deterioration.
8. Inspect the washer that are under the main, options, and umbilical panel
for signs of damage. Replace them as necessary.
9. If the battery has not been used for a long time (we suggest monthly),
recharge it to maintain its life.
If your organization has established a formal Preventive Maintenance
System (PMS) program, the preceding steps can be incorporated into your
regular scheduled maintenance program but should be done frequently.
5.2 SUB-PANEL REPLACEMENT
In the event that the intercom connector sub-panel requires replacement or
you would like to swap the connector style for another, follow the listed
step to remove and then replace the intercom connector sub-panel.

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506279-000 REV. A
1. Ensure that the unit is powered down.
2. Remove the 10 panel screws and washers.
3. Gently lift the panel away from the case and disconnect the panel from
the battery.
4. Turn the panel over so that you can get easy access to the electronics
side of the panel. Gently rest the panel on your work area, allowing the
weight of the panel to rest on the handles.
5. Gently unplug the Sub-panel from the main PCB. In the event that it
is hard to remove, gently rock the connector back and forth until you
can wiggle the connector free.
6. Lift the panel and place it back into place in the case, then remove the
4 sub-panel mounting screws.
7. Lift the sub-panel free from the panel and place the new sub-panel
into position.
8. Replace the sub-panel mounting screws.
9. Flip the panel over and connect the subpanel to the main PCB.
10. Flip the panel over and reconnect the battery wires to the panel.
11. Position the panel into the case, ensuring that no wires are being crushed.
12. Replace the 10 panel screws and washers, tightening in directly opposite
screw locations rst.
13. Ensure that the unit powers back on.
Fig. 8
Fig. 7

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506279-000 REV. A
5.3 TROUBLESHOOTING
The MK-III was designed as high-quality communications equipment.
Nevertheless, as with any electronic equipment, failures occasionally may
occur. The table below provides a list of some problems that might occur,
possible causes, and our recommended solutions to attempt. If you are
experiencing a performance failure of the MK-III that is not mentioned
below, or if you have attempted the suggested solutions and the failure
persists, contact OTS or your local OTS dealer for consultation or repair.
If you need to replace any components or parts, refer to the Spare parts
section for a list of parts and components available from OTS.
Problem Probable Cause Remedy
No power Battery exhausted Recharge battery
Replace battery
Battery leads loose Check battery connec-
tions
Battery does not
charge
Damaged power cable Check power cord
Defective battery Replace battery
No diver voice Microphone type Incom-
patibility
Check for correct
Dynamic/powered mi-
crophone selections.
Poor headset connections Check diver and head-
set connections.
No tender voice Poor tender headset con-
nection
Check tender headset
connection