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FAQ's
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Equipment Calibration
A minimum of an annual calibration is recommended for all test equipment. This servicing should include cleaning of all contacts, earcushions, checking of cords, transducers, replacement of tubing, and most important of all verification of all output levels, frequencies etc. to comply with the relevant standards.
The following are a quick reference to help trouble shoot the most basic problems which occur, when all else fails, consult our experienced customer service staff.
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Phones seem to intermittantly lose signal:
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Check for oxidation at the plugs, transducers and patch cables by spinning the plug in the sockets while the signal is being presented continuously. Usually indicated by crackling., or loss of signal. Clean with a spray type cleaner or wipe with an alcohol pad, and plug & unplug connections which will wipe off oxidation by friction.
Check for lose connections at transducer, set screws on phones should be tight, wiggle cables at transducer and plugs, listen for cut out of signal due to break in cables.
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If earphone/insert transducers dropout intermittantly, cables check out okay:
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Switch left & right at patch panel or audiometer. Right is now left transducer, left is now right transducer. If problem follows to same transducer, that is if the left transducer is still dropping out even when plugged into right output, cord or transducer is defective.
If problem is now located in the right transducer, check the panel connections, patch cables, and connections at audiometer. If all check out okay, possible audiometer intermittancy.
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Headphone/bone conductor do not fit properly:
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The headband tension for these devices has pobably weakened, a simple retensioning of the headband by bending the headband inwards until about 1 to 2 inches of air space is between the two sides of the headband should rectify this.
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Bone conduction at 500, 2000, & 4000 seem irrattic with B71 bone conductor:
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Unfortunately our experience with this approved bone conductor has been a bit problematic. It seems to be very placement sensitive due to the large flat dime shaped contact surface. A tip is to place the bone conductor on the patient, at 500 Hz, and a loud enough intensity for the patient to comfortably tell when it is at it’s loudest when moved on their mastoid without coming against the pinna. This generally gives more reliable test conditions.
If this does not alleviate the problem, we have switched many customers to the older more natural shaped B70AA bone conductor which seems to provide more consistent test results. We have derived custom calibration values for the B70AA, as none are listed in the ANSI standards for this conductor.
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The microphone cables on these instruments tend to fail due to mechanical wear and tear, usually indicated by kinking of cable at mic entrance, poor levelling or irratic test results. Check operators manual for proper calibration checking information.
If a calibrator is available , place mic in calibrator and turn on calibrator, checking measured output on display, you may have to run a test to see this. Slowly move cable at mic entrance, if a break in the cable measurement should jump and be repeatible. If a calibrator is not available, turn signal level on at 80 dB, place mic near signal source, twisting cable as above, signal should drop out or go off scale.
Check connectors for oxidation at instrument, unplugging and plugging several times can help remove oxidation by friction, or use a liquid contact cleaner.
Damaged mics usually show up in higher or lower than normal outputs, noisy responses, or poor levelling. A calibrator is the only method available to check for this.
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Real ear measurement problems:
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Microphones can be checked as above, do not reuse probe tubes or immerse clean them in any liquids as residues and ear wax can migrate down the tubes causing response and output level errors.
The port that the tube slips onto can become plugged, replacement of the microphone assembly would then be required as they are very difficult clean without damaging the mic or upsetting the frequency response.
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These instruments are precision measuring devices and a daily biological check on a known ear or with calibration cavities supplied with most instruments can help verify proper operation. If system fails these checks the following are the major causes we have found.
Check eartips: Replace if hard or cracked, they should be soft and pliable, avoid using Alcohol in the cleaning of eartips as it prematurely destroys the materials used.
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Cleaning Methods:
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A soaking in a 10% bleach and water solution for a couple of hours will sterilize the tips, as well as a 2% Gluteraldehyde and water solution can be used, soaking for overnight. Use precautions with either chemical to prevent contact with eyes & skin. Rinse thoroughly with fresh water, and allow to thoroughly dry before use.
For general cleaning, a anti-bacterial soap and an ultrosonic cleaner are recommended.
Single use tips are available, eliminating any of the above procedures, please call for further information.
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Operational problems:
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One of the most common problems with these instruments is the accumulation of wax in the probe tip, causing high volumes, flat responses, or reflex artifacts. Clean with supplied tip cleaners, some tips require the probe tubing be removed to perform this, do not push wax up into the probe tip. Consult operation manual for proper procedure or call our technical personnel.
Check probe tubing for signs of wax infiltration, if so replace with exact same length and type of tubing to ensure calibration accuracy.
The probe cable on these devices is where the highest amount of mechanical failure generally occurs (aside from damage from dropping of the probe). This can be indicated by high volumes, leaks, intermittant probe\ipsi levels or irratic operation. Try to keep the cable straightened as much as possible as twisting of the cable causes premature weakening of the cables and can cause the air hose inside the cable to pinch, decreasing or stopping the pressure from getting to the probe tip creating another set of problems.
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Copyright © 1999, Electro-Medical Instrument Co. All Rights Reserved.
All logos or trademarks are the property of their respective owners.
Price subjects to change without notice. Products may differ from illustration.
Web Master: webmaster@dinocom.com http://www.dinocom.com
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