Amron 8895-AMP-8 User manual

User Manual
for
Amron International Diving Supply, Inc.
Model 8895-AMP-8
Model 8895-AMP-16
Entertainment Amplifier
S/N__________________
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 Diving Supply, Inc.
reserves the right to change specifications without notice.
Amron International Diving Supply, Inc
1380 Aspen Way, Vista, California 92081 U.S.A
Phone [phone] Fax [phone]
Email: [email protected]
Web : www.amronintl.com
Copyright @ 1998, Amron International, Inc.
Revised October 2010

TABLE OF CONTENTS
SECTION
Specifications 1
Electrical .......................................................................................................................1.1
Power............................................................................................................................1.2
Mechanical....................................................................................................................1.3
Size...............................................................................................................................1.4
General Information 2
General Information ......................................................................................................2.1
Figure 1 Picture 8895-AMP-8........................................................................................2.2
Figure 2 Picture 8895-AMP-8 (rear)..............................................................................2.3
Options and Accessories 3
Accessories...................................................................................................................3.1
Warranty and Service Policy 4
Limited Warranty...........................................................................................................4.1
Service Policy................................................................................................................4.2
Controls and Connections 5
Controls and Connections ............................................................................................5.1
Installation and Operation 6
Operation ......................................................................................................................6.1
Installation.....................................................................................................................6.2
Theory of Operation 7
Theory of Operation......................................................................................................7.1
Functional Block Diagram.............................................................................................7.2
I

TABLE OF CONTENTS
II
Maintenance 8
Periodic Tests and Checks ...........................................................................................8.1
Drawings and Schematics 9
General .........................................................................................................................9.1
Schematic, Model 8895-AMP-8 ....................................................................................9.2
Schematic, Model 8895-AMP-16 ..................................................................................9.3
Schematic, Audio 1 & 2 8895-200 PC Card..................................................................9.4
Schematic, Audio 3 & 4 8895-200 PC Card..................................................................9.5
Schematic, Audio 5 & 6 8895-200 PC Card..................................................................9.6
Schematic, Audio 7 & 8 8895-200 PC Card..................................................................9.7
Schematic, Input Audio & Power 8895-200 PC Card....................................................9.8
System Interconnect Diagram Model 8895...................................................................9.9
Cable Assembly Model 8895-600...............................................................................9.10
Outside Junction Box Diagram Model 8895-700.........................................................9.11
Inside Junction Box Diagram Model 8895-800 ...........................................................9.12
Parts Identifier, Models 8895-AMP-8 & -16, Front......................................................9.13
Parts Identifier, Model 8895-AMP-8, Back..................................................................9.14
Parts Identifier, Model 8895-AMP-16, Back................................................................9.15
Outside Junction Box Model 8895-700.......................................................................9.16
Parts Identifier, Model 8895-700.................................................................................9.17
Inside Junction Box Model 8895-800..........................................................................9.18
Parts Identifier, Model 8895-800.................................................................................9.19
Parts List 10
General .......................................................................................................................10.1
Model 8895-AMP-8, Top Assembly ............................................................................10.2
Model 8895-AMP-16, Top Assembly ..........................................................................10.3
Model 8895-005, Pneumatic Headset for O2 Hood....................................................10.4
Model 8895-100, Patient Entertainment Set...............................................................10.5
Model 8895-600, Cable Assembly, 20 Foot Length....................................................10.6
Model 8895-700, Junction Box, Outside.....................................................................10.7
Model 8895-800, Junction Box, Inside........................................................................10.8
Model 8895-8-500, Chassis & Rear Panel Assembly.................................................10.9
Model 8895-16-500, Chassis & Rear Panel Assembly.............................................10.10
Model 8895-200A, PC Card Assembly .....................................................................10.11

SPECIFICATIONS
ELECTRICAL 1.1
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
POWER 1.2
A. C. Power............................................................................ 115/220 Volts AC 50/60 Hz
Isolation Transformer.............................................................Split Bobbin Medical Grade
MECHANICAL 1.3
Enclosure ............................................................................... Black Anodized Aluminum
SIZE 1.4
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)
1

GENERAL INFORMATION
GENERAL INFORMATION 2.1
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 (the same type as used by the airline industry) to provide
audio entertainment for passengers. 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.
2

GENERAL INFORMATION
PICTURE OF THE MODEL 8895-AMP-8 2.2
3

GENERAL INFORMATION
PICTURE OF THE MODEL 8895-AMP-8 (rear) 2.3
4

OPTIONS
ACCESSORIES 3.1
Model 8895-005
Pneumatic Headset has dual ear muffs with male Q.D.
Model 8895-100
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.)
Model 8895-600
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.
Model 8895-700
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.
Model 8895-800
Inside Junction Box has male adapter busing 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.
5

WARRANTY AND SERVICE POLICY
LIMITED WARRANTY 4.1
AMRON INTERNATIONAL DIVING SUPPLY, INC. warrants that its products are free from
defects in material and workmanship under normal use and service (as described in AMRON
INTERNATIONAL DIVING SUPPLY, Inc. literature covering this product) for a period of 90 days
from date of shipment. Amron's obligation under this warranty is limited to the repair or
replacement of defective material at AMRON'S option. This warranty shall not cover defects which
are the result of misuse, negligence, accident, repair or alterations.
SERVICE POLICY 4.2
AMRON INTERNATIONAL encourages owners of equipment to call [phone] for
assistance if problems are encountered. Every effort will be made to assist in solving your
problem. Equipment which must be returned to the factory for repairs should be safely packaged,
insured, and shipped prepaid to:
Amron International, Inc.
1380 Aspen Way
Vista, CA 92081
Be sure to include the following information:
Your Name
Your Company Name
Shipping Address
Phone Number
Contact Name
A short description of the problem is most helpful.
Valid in warranty repairs will be made at no charge. Out of warranty repairs will be handled in the
same fashion, except you will be advised of the repair charges before any work is done.
6

INSTALLATION & OPERATION
OPERATION 6.1
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.
8

INSTALLATION & OPERATION
9
INSTALLATION 6.2
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.
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.

THEORY OF OPERATION
THEORY OF OPERATION 7.1
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.
The entertainment module contains an audio transducer which produces an audio sound pressure
wave to drive a pneumatic headset similar to those used by the airline industry for in-flight audio
entertainment. 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 I.C. 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.
10

THEORY OF OPERATION
FUNCTIONAL BLOCK DIAGRAM 7.2
11

MAINTENANCE
PERIODIC TESTS & CHECKS 8.1
The patient entertainment module pressure integrity should be checked annually. This can be
done without disturbing 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, check the o-ring on the back side of the
audio transducer. If a leak is detected, do not use this patient entertainment module/headset in an
oxygen enriched environment.
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.
12

DRAWINGS
General 9.1
The following drawings illustrate the electrical and mechanical details of the patient entertainment
units. The corresponding parts lists for each drawing are detailed in the parts lists section, or are
included as part of the drawing.
Revisions
When drawings are updated, information about changes is incorporated into a revision sheet. This
revision sheet appears in the manual immediately after the drawings. It lists the drawing number, the
reference designator of the part or parts involved, a description of the revision, and the effective serial
number of the change. With this information the technician can determine the correct drawing for the
current version and any previous version of the unit covered by this manual. If the revision is
applicable for all versions of the unit, it is not included in the revision notice, as the change applies to
all units.
13

DRAWINGS
SCHEMATIC, MODEL 8895-AMP-8 9.2
14

DRAWINGS
SCHEMATIC, MODEL 8895-AMP-16 9.3
15

DRAWINGS
SCHEMATIC, AUDIO 1 & 2 8895-200 PC CARD 9.4
16

DRAWINGS
SCHEMATIC, AUDIO 3 & 4 8895-200 PC CARD 9.5
17

DRAWINGS
SCHEMATIC, AUDIO 5 & 6 8895-200 PC CARD 9.6
18