Amron 8895-AMP-8 User manual

8895-UM REV 1.0
User Manual
for
Amron International, Inc.
Model 8895-AMP-8
Model 8895-AMP-16
S/N______________________
1380 Aspen Way, Vista California 92081-8349
United States of America
Phone: [phone]
Fax [phone]
email: [e-mail]
web: www.amronintl.com
This manual and the information contained herein are provided for use as an operation and
maintenance guide. No license or rights to manufacture, reproduce, or sell either the manual or
articles described herein are given. Amron International, Inc. reserves the right to change
specifications without notice. Copyright© 2013 Amron International, Inc.

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TABLE OF CONTENTS
1. INTRODUCTION AND SPECIFICATIONS ........................................................................................................... 3
INTRODUCTION..............................................................................................................................................31.1
ELECTRICAL SPECIFICATIONS .........................................................................................................................31.2
POWER...........................................................................................................................................................31.3
MECHANICAL .................................................................................................................................................41.4
2. WARRANTY AND SERVICE POLICY .................................................................................................................. 5
LIMITED WARRANTY ......................................................................................................................................52.1
SERVICE POLICY..............................................................................................................................................52.2
3. ACCESSORIES.................................................................................................................................................. 6
8895-005........................................................................................................................................................6
3.1
8895-100........................................................................................................................................................63.2
8895-600........................................................................................................................................................63.3
8895-700........................................................................................................................................................63.4
8895-800........................................................................................................................................................63.5
4. CONTROLS AND CONNECTIONS...................................................................................................................... 7
FRONT PANEL CONTROLS...............................................................................................................................74.1
REAR PANEL CONNECTIONS...........................................................................................................................74.2
5. INSTALLATION AND OPERATION .................................................................................................................... 7
INSTALLATION................................................................................................................................................75.1
OPERATION ....................................................................................................................................................85.2
THEORY OF OPERATION .................................................................................................................................85.3
FUNCTIONAL BLOCK DIAGRAM....................................................................................................................105.4
6. MAINTENANCE............................................................................................................................................. 11
7. DRAWINGS................................................................................................................................................... 12
SCHEMATIC, MODEL 8895-AMP-8 ...............................................................................................................137.1
SCHEMATIC, MODEL 8895-AMP-16 .............................................................................................................147.2
SCHEMATIC, AUDIO 1&28895-200 PC CARD..............................................................................................157.3
SCHEMATIC, AUDIO 3&48895-200 PC CARD..............................................................................................167.4
SCHEMATIC, AUDIO 5&68895-200 PC CARD..............................................................................................177.5
SCHEMATIC, AUDIO 7&88895-200 PC CARD..............................................................................................187.6
SCHEMATIC, INPUT AUDIO &POWER 8895-200 PC CARD............................................................................197.7
SYSTEM INTERCONNECT DIAGRAM MODEL 8895........................................................................................207.8
CABLE ASSEMBLY MODEL 8895-600 ............................................................................................................217.9
OUTSIDE JUNCTION BOX DIAGRAM MODEL 8895-700 ................................................................................227.10
INSIDE JUNCTION BOX DIAGRAM MODEL 8895-800....................................................................................237.11
PARTS IDENTIFIER MODEL 8895-AMP-8 &-16, FRONT ................................................................................247.12
PARTS IDENTIFIER MODEL 8895-AMP-8, BACK ............................................................................................257.13
PARTS IDENTIFIER MODEL 8895-AMP-16, BACK ..........................................................................................267.14
OUTSIDE JUNCTION BOX MODEL 8895-700 .................................................................................................277.15

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PARTS IDENTIFIER MODEL 8895-700............................................................................................................28
7.16
INSIDE JUNCTION BOX MODEL 8895-800.....................................................................................................297.17
PARTS IDENTIFIER MODEL 8895-800............................................................................................................307.18
8. PARTS LIST GENERAL .................................................................................................................................... 31
MODEL 8895-AMP-8, TOP ASSEMBLY ..........................................................................................................328.1
MODEL 8895-AMP-16, TOP ASSEMBLY ........................................................................................................328.2
MODEL 8895-005, PNEUMATIC HEADSET FOR O2 HOOD ............................................................................338.3
MODEL 8895-100, PATIENT ENTERTAINMENT SET ......................................................................................338.4
MODEL 8895-600, CABLE ASSEMBLY, 20 FOOT LENGTH ..............................................................................338.5
MODEL 8895-700, JUNCTION BOX (OUTSIDE)..............................................................................................348.6
MODEL 8895-800, JUNCTION BOX (INSIDE) .................................................................................................358.7
MODEL 8895-8-500, CHASSIS &REAR PANEL ASSEMBLY .............................................................................358.8
MODEL 8895-16-500, CHASSIS &REAR PANEL ASSEMBLY ...........................................................................378.9
MODEL 8895-200A, PC CARD ASSEMBLY .....................................................................................................388.10

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1. INTRODUCTION AND SPECIFICATIONS
INTRODUCTION1.1
The Model 8895-AMP-8 & 8895-AMP-16 Entertainment Amplifiers are four-channel audio
amplifiers designed to provide entertainment audio to patients within a hyperbaric chamber
environment. The amplifier is one part of a complete system to provide entertainment audio.
Amron has all the components available to build a complete system, including cables.
Patients wear a pneumatic headset to provide audio entertainment. This configuration was
selected so that the patients could use the headset while receiving oxygen treatment and still
safely have audio entertainment. No electrical energy is present at the headset. Volume
level is adjustable by each patient, and each patient has channel selection control. Up to four
audio selections can be provided.
The patient headset is driven by a patient entertainment module which converts the electrical
signal to a sound pressure wave to drive the pneumatic headset. The audio transducer is
isolated from the pneumatic headset via a diaphragm. The electrical signal to the patient
entertainment module is a low voltage/low wattage signal, typically one watt with a maximum
voltage of 12 VDC. A volume control is provided as part of the headset tubing, allowing each
patient to adjust their listening level.
Each patient entertainment module has channel selection capabilities. A push-button switch
allows the patient to step through up to four different selections of audio. Again, in keeping
with the safety issues of a chamber environment, the electrical switching is done with low
voltage current, limited logic level signals. Up to eight patient entertainment modules can be
driven by the 8895-AMP-8 and sixteen can be driven by the 8895-AMP-16.
A 110/220 volt selector switch is located on the rear of both the Model 8895-AMP-8 & 8895-
AMP-16. Select the desired voltage by turning the sector switch with a small slotted
screwdriver.
ELECTRICAL SPECIFICATIONS1.2
Input Channels............................................................................................................ 4 Stereo
Input Impedance (Each Input)................................................................................... 600 Ohms
Frequency Response..................................................................................... 100 Hz to 30 kHz
Sensitivity (Input) ...............................................................................................................1 mV
Output Channels ......................................................................................................................8
Output Power per Channel (RMS @ 8 Ohm Load).......................................................¼ Watts
Output Impedance.........................................................................................Less than 8 Ohms
POWER1.3
A.C. Power..................................................................................... 115/220 Volts AC 50/60 Hz
Isolation Transformer ..................................................................... Split Bobbin Medical Grade

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MECHANICAL
1.4
Enclosure ....................................................................................... Black Anodized Aluminum
Length ............................................................................................................13.0 in. (33.0 cm)
Width..............................................................................................................17.0 in. (43.2 cm)
Height...............................................................................................................3.5 in. (8.9 cm)
Weight .............................................................................................................7.3 Lbs. (3.3 kg)

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2. WARRANTY AND SERVICE POLICY
LIMITED WARRANTY2.1
Amron warrants that its manufactured products are free from defects in material and
workmanship under normal use and service, as described in all literature covering the
products for a period of 90 days from date of shipment. Amron’s obligations under this
warranty are limited to the repair of, or replacement of materials at Amron’s discretion. This
warranty shall not cover defects which are the result of misuse, negligence, accident, repair,
or alterations.
SERVICE POLICY2.2
For technical assistance or to request a repair please call [phone] Monday-Friday,
6am-5pm PST. Please do not return any product without an authorization number. After
obtaining a return authorization number, wrap and pack the item securely and ship to the
following address. We suggest that you use a carrier that provides tracking information and
insure the item for full replacement value.
Amron International, Inc.
Attn: Repairs Department
1380 Aspen Way
Vista, CA 92081
Be sure to reference the return authorization number on the shipment. For non-warrantable
repairs, a minimum evaluation fee will be charged. A written evaluation and quote will be
provided for approval before Amron proceeds with the repairs.

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3. ACCESSORIES
8895-0053.1
Pneumatic Headset has dual ear muffs with male Q.D.
8895-1003.2
Patient Entertainment Set contains audio sound transducer and channel selector switch.
Comes complete with 20 foot electrical hookup cable, 5 ½ foot sound tubing (includes
volume control and female Q. D.)
8895-6003.3
Cable Assembly connects amplifier 8895-AMP-8 to outside junction box on chamber.
Handles audio and channel selection signals for up to 8 patient entertainment modules. Two
cable assemblies required for the 8895-AMP-16 amplifier unit. Cable Assembly is 20 feet
long, other lengths available on special order.
8895-7003.4
Outside Junction Box has connector to mate with 8895-600 cable assembly and an electrical
penetrator (20 conductor, ¾” Male NPT) to mount to chamber. Unit is pre-assembled and
tested, ready to screw into the chamber penetrator.
8895-8003.5
Inside Junction Box has male adapter bushing to mount to chamber penetrator (3/4” Male
NPT) and terminal boards to attach electrical feed-thru wires from 8895-700. Two cable
grommets protect the cables from the patient entertainment modules as they enter the
junction box. Entertainment modules are wired to the terminal boards to complete the
installation.

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4. CONTROLS AND CONNECTIONS
Before using the Entertainment System, you should familiarize yourself with the controls and
connections. Improper use of the controls and connections may deprive the user of the full benefits
of the system.
FRONT PANEL CONTROLS4.1
4.1.1 Power Switch –Turns AC Power on/off.
4.1.2 Power Indicator –Confirms power is on or off
4.1.3 Source Input Volume Level Controls –Used to balance the volume levels from
different sources, one of each of the four inputs
4.1.4 MV –Master Volume control
REAR PANEL CONNECTIONS4.2
4.2.1 AC Power Cord –Connect to AC power source
4.2.2 Entertainment output (1 thru 8) –MS Cable attachment point for studio to patient
entertainment modules.
4.2.3 Source A Input (L&R) - RCA audio jack for connection to audio source i.e., AM/FM
tuner, recording device, CD, DVD, or MP3 player, or TV audio out. Stereo input for
left and right channels.
4.2.4 Source B Input (L&R) - RCA audio jack for connection to audio source i.e., AM/FM
tuner, recording device, CD, DVD, or MP3 player, or TV audio out. Stereo input for
left and right channels.
4.2.5 Source C Input (L&R) - RCA audio jack for connection to audio source i.e., AM/FM
tuner, recording device, CD, DVD, or MP3 player, or TV audio out. Stereo input for
left and right channels.
4.2.6 Source D Input (L&R) - RCA audio jack for connection to audio source i.e., AM/FM
tuner, recording device, CD, DVD, or MP3 player, or TV audio out. Stereo input for
left and right channels.
4.2.7 Entertainment Output (9 thru 16, Model 8895-AMP-16 only) - MS cable attachment
point for audio to patient entertainment modules.
5. INSTALLATION AND OPERATION
INSTALLATION5.1
If you have purchased a complete system, begin by installing all components. The patient
entertainment module should be installed in a convenient location for the patient to reach
while seated in a normal position. Patient will need to be able to reach the yellow push
button switch in order to change channels.

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The outer junction box should be installed before the inner junction box. This makes it easier
to feed the wires through the chamber penetrator. After both junction boxes are installed,
connect the electrical feed-thru wires in the inside junction box. Next you will want to run the
patient entertainment module cables to the inside junction box, routing the cable through one
of the appropriate strain reliefs. Connect the wires from the patient entertainment module as
shown on the System Interconnect Diagram, DWG NO. 8895-SYS-D101. There are four
wires from each module, two are clear and two are blue in color. Use an ohmmeter to
identify the clear wire with the switch in the line and connect as shown. Next identify the
blue wire on the side opposite the speaker from the switch and connect as shown. Connect
the remaining wires, clear and blue as shown.
Route and install the cable between the amplifier and the outer junction box. Connect the
amplifier to the audio source components and check out the system confirming the presence
of audio and proper operation of the channel selector.
OPERATION5.2
Turn power on and confirm power is on by observing the power on indicator. Make
sure all sources of audio are on and operating properly.
On initial set up, set all volume controls on the source devices to minimum and all front
panel volume controls to mid-scale. Use one of the headsets within the chamber,
making sure the volume control valve on the sound tubing is full “ON”. Slowly advance
source “A” while listening to the headset within the chamber. Cycle the source selector
switch to locate the presence of audio and confirm the operation of the system.
Set the volume level for source “A” for a comfortable level on the headset in the
chamber. Repeat this procedure for source “B”, being sure to first advance the channel
selector one step. After setting channel “B”, repeat this procedure for channels “C” &
“D”. If you are not going to have four sources of audio material, you can leave a channel
open (nothing connected) or you can put the same material on multiple channels using
a “Y” cable available from any retailer selling audio equipment (female jack to two male
jacks).
Once the volume levels are set for the four channels, note the position of the volume
controls on the source equipment.
The volume controls on the front panel adjust the range of audio levels which the
amplifier will accommodate. If you have a source of material which has a low output
you can increase the sensitivity of that channel without affecting the other channels.
The master volume (MV) controls the output of the amplifier and adjusts the volume
level to all patient entertainment modules.
Once a proper level is achieved no further adjustment should be necessary.
THEORY OF OPERATION5.3
The 8895-AMP-8 & 8895-AMP-16 are built in two configurations, an 8-patient and a 16-
patient version. There are eight output audio amplifiers in the -8 and sixteen in the -16, each
driving one patient entertainment module. Each of the amplifier’s inputs can be remotely
controlled to select one of four input sources of audio. The remote source selection is done
by a push button on the patient entertainment module.

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The entertainment module contains an audio transducer which produces an audio sound
pressure wave to drive a pneumatic headset. The entertainment module has a diaphragm to
separate the transducer from the sound tube. This prevents the possibility of the back flow of
oxygen into the transducer when the headset is being used in an oxygen enriched area such
as an oxygen treatment hood.
The amplifier unit has four stereo inputs, each having a left and right audio input. This allows
the system to be connected to a stereo source. The stereo information is mixed using a
center taped transformer. The transformer also provides isolation from the source
equipment. The output of the transformer is fed to a potentiometer to control the signal level.
The output of the volume control is fed to an operational amplifier to buffer the signal. There
are four separate circuits, one for each of the four input sources of audio. This input section
has two output jacks, J6 & J8, which feeds the audio output section of the amplifier card.
The audio output amplifier is fed by one of the four input audio sources. The patient controls
the source by activating the channel selector button. The contact closure is de-bounced and
steps a ring counter. The ring counter output is buffered and decoded from binary by a
series of “AND” gates. The output of the “AND” gates drives a four pole analog switch which
routes one of the four input audio sources of the input of the final audio output amplifier. The
selection of audio sources is “A”, “B”, “C” and “D”; and then repeats beginning with “A”.
The audio amplifier IC is a stereo unit. Each side is used for separate channels. Each unit
has a separate volume control which is voltage controlled. All amplifiers are controlled from a
common volume control. The output of each amplifier’s current is limited by resistors and
capacity; and is coupled to eliminate any D.C. voltage which might appear on the output.
All of these circuits are powered from a common power supply. The supply uses fuses
mounted on the P.C. card. Fuses are ½ amps and each side of the line is fused. The AC
power switch interrupts the AC line before the power transformer. The power transformer is
a medical grade transformer providing excellent isolation from the line and low leakage
current. A full wave rectifier, filter capacitors (C23, C35 & C34), and two 3-terminal fixed
voltage regulators are used. The first regulator is 15 Volts and the second is 5 Volts.
On the 8895-AMP-16 a second amplifier card is used. The second card uses the same
power transformer as the first card. Also the input audio section of the first card is bused to
the second card. The input volume controls on the second card are not used, and left off the
card along with the AC power switch. All other circuits of the second remain functional and
operate in the same manner as the first card.

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FUNCTIONAL BLOCK DIAGRAM
5.4

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6. MAINTENANCE
The patient entertainment module pressure integrity should be checked annually. This can be done
without disturbing the module. Remove the headset and pressurize the tubing line to the
entertainment module with 10 PSI of air. The module should hold this pressure without loss for a
period of 60 seconds. If the unit does not hold pressure, do not use this patient entertainment
module/headset in an oxygen enriched environment and return to Amron for service.
No other specific routine maintenance is required. No preventative maintenance is required. A
functional check of all circuits may be desirable; however, a problem report by the end user will
identify any problems.

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7. DRAWINGS
The following drawings illustrate the electrical and mechanical details of the diver communication
unit. The corresponding parts lists for each drawing are detailed in the parts lists section, or are
included as part of the drawing. All drawings are at their current revision level as of the date of
printing. Amron reserves the rights to revise the documentation without notification.

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SCHEMATIC, MODEL 8895-AMP-8
7.1

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SCHEMATIC, MODEL 8895-AMP-16
7.2

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SCHEMATIC, AUDIO 1 & 2 8895-200 PC CARD
7.3

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SCHEMATIC, AUDIO 3 & 4 8895-200 PC CARD
7.4

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SCHEMATIC, AUDIO 5 & 6 8895-200 PC CARD
7.5

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SCHEMATIC, AUDIO 7 & 8 8895-200 PC CARD
7.6

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SCHEMATIC, INPUT AUDIO & POWER 8895-200 PC CARD
7.7