Welch Allyn GSI TM262 User manual

2.6 INITIAL SETUP

Place the TM 262TM Auto TympTM on a stable counter or table where it
will subsequently be used, and near a properly grounded wall outlet.
Attach accessories to their appropriately-labled connectors on the rear
panel of the TM 262 (see Figure 2-9).

Locate the POWER switch on the rear panel of the TM 262 and move
the switch to the ON ( ) position. Note that the lamp (F1) on the front
panel is illuminated, indicating the TM 262 is receiving power. The
TM 262 symbol will then appear on the display along with a listing of
the revision number for the Tymp/Reflex and Audiometry (if purchased)
software. Next, the display will default to the Tymp/Reflex mode and
the probe’s green lamp will begin to blink, indicating that the TM 262 is
ready to begin a test. If both the green and yellow lamps are illumi­nated at the same time, either the probe is occluded or the tymp/
reflex software did not properly initialize. Simply move the power
switch to the OFF ( ) position, inspect the probe tip for any signs of
an occlusion, and reposition the power switch to ON ( ). If both green
and yellow lamps are still illuminated and you are certain that the
probe is not occluded, contact the Welch Allyn Technical Service
Department (see page 55). In the meantime, it is still possible to
select the Audiometry mode (if purchased).

Allow the instrument to warm-up for about five minutes before conduct­ing a test. This allows the electronic circuits to stabilize prior to use.
If the storage temperature is lower than the room temperature, allow
some additional time for the instrument to reach room temperature.

Warning

The TM 262 is designed to be used with a hospital grade outlet. Injury to per­sonnel or damage to equipment can result when a three-prong to two-prong
adapter is connected between the TM 262 power plug and an AC outlet or
extension cord. Additionally, those TM 262 Auto Tymps that are equipped with
power transformers use a specific transformer (8000-0260, 8000-0261 or 8000-

0262) which should not be interchanged with any other transformer or supply.
The TM 262 is a specifically-calibrated device and the periodic service and
adjustments which the instrument may require should be done only by an

authorized Welch Allyn service technician.

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2.6.1 Loading The Paper

Remove the printer cover (see Fig. 2-3 for location) by placing your fin­gers along the back edge of the printer and pulling upward on the cover.
Cut the printer paper so that the leading edge of paper is straight across.
Place the roll of paper inside the paper well so that the paper will unroll
from the lower surface. See paper loading label for additional help
(Figure 2-11).

Paper exit

Paper loading
label

PAPER LOADING

INSERT THE LEADING EDGE SQUARELY INTO

THE PAPER ENTRANCE WHILE PRESSING THE

PAPER ADVANCE ON THE FRONT PANEL

FIGURE 2-11: Paper Loading

Position the leading edge of the paper roll into the paper entrance while
pressing the PAPER ADVANCE button. The paper will begin to ap­pear out of the printer mechanism. Continue to advance the paper so
that a section of paper is long enough to pass through the printer cover
once it is repositioned over the printer.

Paper
entrance

2.6.2 Paper Storage

The TM 262TM Auto TympTM utilizes a thermal printer, which requires a
heat-sensitive paper to create an image. For maximum paper life, any
spare rolls of paper should be stored as follows:

1) Store in the dark, i.e., in a drawer or cabinet

2) Do not store above 77°F (25°C)

3) Store at less than 65% relative humidity

The above recommendations are for the maximum paper life (greater
than five years). Storing your TM 262 thermal paper at high temperatures
or high humidity levels will only shorten the total paper life.

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2.7 PRETEST TYMPANOMETRY CHECKS

For your convenience, a test cavity is provided with your TM 262
Auto TympTM. This test cavity enables you to quickly verify the proper
calibration of your unit. Welch Allyn, Inc. strongly recommends that
you make this quick check a part of your daily routine.

2.7.1 Calibration

To initiate the quick check, select the Tymp only mode and insert
the probe (without a tip on it) into the 0.5 cm3 opening on the test
cavity. See Figure 2-12.

NOTE

Since the TM 262 is designed to start automatically, it is important that the
probe is inserted as quickly and as smoothly as possible. During the calibra­tion check, the probe must be held carefully and without movement. Do not
place the probe on the same counter as the instrument or any moving object
during this check, as mechanical noise will be picked up by the probe and
interfere with the calibration check.

3

0.5 cm

3

2.0 cm

TYMP

5.0 cm

3

TM

FIGURE 2-12: Test Cavity

The calibration check will start automatically if the probe has been in­serted into the cavity properly. This is confirmed by the green lamp
changing from blinking to a steady condition. If the orange lamp is illu­minated, the probe is not properly positioned within the cavity so that
a large pressure leak exists. If the yellow lamp is illuminated, the probe
tip has been occluded. In either case, remove the probe and wait for
the blinking green lamp. Insert the probe once again. Clean the probe
tip if necessary (see Section 3.2).

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When the test sequence is completed, the green lamp on the probe is
no longer illuminated. Remove the probe from the test cavity and note
that the green lamp is blinking once again. The display will indicate a
flat line on the tympanogram along with the value of the test cavity next
to the letters ECV (ear canal volume), i.e., 0.5. The letters NP will ap­pear next to the labels cm3 and daPa and three dashed lines will ap­pear next to the letters GR (gradient). Since the test cavity is a hard­walled cavity, the tympanogram should be a flat line, indicating that
there is no mobility in the system. The TM 262TM Auto TympTM places the
letters NP next to the cm3 and daPa headers to indicate that there is no
peak compliance and, therefore, no peak pressure can be determined
during the quick check. Also, since there is no compliance peak de­tected, it is not possible to calculate a gradient. Therefore, the TM 262
displays the dashed lines when a gradient calculation isn’t possible.

Using the same sequence, place the probe in the test-cavity opening la­belled 2.0 cm3. Note that the display looks the same as with the 0.5 cm
measurement, except for the value placed next to the letters ECV (2.0).
If you wish, the same sequence can be followed with the 5.0 cm3 open­ing on the test cavity. To keep a record of this test-cavity-calibration
check, simply press the PRINT ALL button on the front panel of
the TM 262.

2.7.2 Altitude Adjustment

Since sound pressure will vary with altitude and barometric pressure,
some variation from the 0.5, 2.0 and 5.0 cm3 readings may be observed.
Your TM 262 is carefully calibrated at our factory, which is at approxi­mately 250 feet above sea level. If you are located at an elevation of
1000 feet or higher, your instrument may need to be recalibrated to
account for your elevation. It is not necessary to recalibrate for baro­metric pressure changes on a daily basis. Just keep in mind that a
change in barometric pressure (i.e., from low to high or high to low)
will slightly affect the test-cavity readings.

The altitude calibration adjustment allows for “corrections” to the Ear
Canal Volume (ECV) measurement and test cavity volume measure­ment for variations due to altitude. Because the TM 262 is a pressure­sensitive device which makes measurements relative to ambient air
pressure, changes in air pressure due to weather or altitude will affect
the Ear Canal Volume (ECV) read-out of the instrument. The slight pres­sure change resulting from changing weather conditions will usually
yield volume read-outs within ±0.1 cm3 of the expected cavity value;
however, pressure changes due to altitude can shift these cavity values
by as much as 30%. These changes in pressure do not affect the

accuracy of the compliance measurement system in any way.

But, many instrument operators prefer that their equipment give ECV
values as they would appear at sea level. The altitude calibration mode
allows the operator to adjust his/her Auto Tymp without the services of
a qualified Welch Allyn Service Technician.

3

14

TABLE 2-2: Altitude Correction

Altitude Correction

Altitude (ft.) Altitude Table (cm3)
0 to 1,500 2.0
2,000 to 3,500 2.1 ± 0.1
4,000 to 6,000 2.2 ± 0.1
6,500 to 7,500 2.3 ± 0.1
8,000 to 9,000 2.4 ± 0.1
9,500 to 10,000 2.5 ± 0.1

The altitude calibration mode can only be entered when the TM 262 is
powered up from its “off” state while the PROGRAM mode button,
is depressed. Hold the PROGRAM button for approximately

PROG

PROG

five seconds.

STEP 1

When entering the altitude mode the display will read as follows:

Altitude Mode
ECV 2.0

3

9.99

cm

Standard
(E71) is displayed in the bottom right corner of the display until the probe is
in the 2.0 cm

STEP 2

Place the probe into the 2.0 cm
check cm

STEP 3

If the measured volume is not within the published table value ±0.1cc, then
the operator should exit the altitude mode by pressing the PROGRAM
button and contact field service.

Providing the measured volume agrees with the published table ±0.1cc,
the operator may proceed with the altitude adjustment.

STEP 4

With the probe still in the 2.0 cm
enter the custom calibration mode. Custom will appear on the fourth line
of the display.

3

cavity.

3

3

value against the altitude correction table for accuracy.

cavity provided with the instrument and

3

cavity, select the PAGE button to

PAGE

PROG

STEP 5

The value now displayed in the cm

3

display area is the volume measured
and adjusted to the current altitude. If the value displayed is 2.0 cc, then
the volume is adjusted to the current site. If the value is not 2.0 cc ±0.1,
then press the SAVE button to customize the volume measurement

M+

to the current altitude. The measured volume should now read 2.0 cc.

STEP 6

To exit the altitude mode, press the PROGRAM button to return to

PROG

normal mode.

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2.8 PRETEST AUDIOMETRIC CHECKS
(Models with Audiometer Only)

2.8.1 Noise Recovery Period

Exposure to high levels of sound (e.g., unmuffled lawn mowers, loud
music, gunfire) tends to create a Temporary Threshold Shift (TTS) which
diminishes with time after exposure. Any subject tested soon after such
exposure may exhibit a hearing loss that does not reflect his/her normal
hearing threshold. This test procedure, therefore, generally prescribes a
16 hour interval between the last exposure to high-level sounds and the
administration of any hearing test.

2.8.2 Elimination of Ambient Noise

Excessive noise in the test environment during audiometric testing,
such as that produced by conversation, computers and public address
systems reduces test validity because it tends to mask the test signals,
particularly at the lower frequencies where earphone cushions provide
less effective attenuation. An acoustically-treated room may be
required if ambient noise reaches objectionable levels, i.e., sufficient
to cause apparent hearing loss at the low frequencies. Also, earphone
sound enclosures are available from Welch Allyn as an optional
accessory. If the person being tested is in the same room as the
audiometer, it is recommended that he/she be seated about three
feet (one meter) away from the TM 262TM Auto TympTM.

Maximum permissible noise levels are specified by the American Na­tional Standards Institute—Criteria for Permissible Background Noise
during Audiometric Testing, ears covered with earphones (S3.1-1991
revised). Table 2-3 shows the maximum background levels that can be
present inside the room while a valid hearing test is being conducted.
For more comprehensive information about hearing testing and hearing
conservation, refer to the Bibliography.

TABLE 2-3: Permissible Noise Levels

Test Tone

Frequency (Hz) 125 250 500 750 1000 1500 2000 3000 4000 6000 8000

Test Room

Ears covered 34.0 22.5 19.5 21.5 26.5 26.5 28.0 33.5 34.5 38.0 43.5
maximum
permissible octave
band levels

Ears covered
maximum
permissible one-third
octave band levels

29.0 17.5 14.5 16.5 21.5 21.5 23.0 28.5 29.5 33.0 38.5

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2.9 BIOLOGICAL CHECK

To determine that your TM 262 is functioning properly, perform a daily
check on a normal ear—your own if possible. This allows you to listen
for the probe tone and the stimulus tone (during reflex) and determine if
the air-pressure system is working properly. Keep a copy of your chart
for a day-to-day reference in checking your TM 262.

If you purchased the TM 262TM Auto TympTM with audiometry, select the
AUDIOMETRY button located in the center section of the front
panel. Note that the display changes to an audiogram format. The Hz
and Hz buttons allow you to select each frequency and the dB
HL knob allows you to alter the intensity of each frequency. Position the
test headset on your head so that each earphone is covering the ap­propriate ear (i.e., red is right and blue is left). Select the right earphone
by pressing the front panel button labelled R and check for the follow­ing while depressing the present bar:

• Depressing the Hz button causes the frequency to change to
a lower frequency, depressing the Hz button causes the fre­quency to change to a higher frequency.

• Each frequency or tone is pure, i.e., there is no distortion or
crackling sound present.

• Rotating the dB HL knob in a clockwise direction increases in
intensity of the tone.

• Rotating the dB HL knob in a counter-clockwise direction de­creases the intensity of the tone.

AUD

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Specifications

STANDARDS:

IEC 601-1 Medical Electrical Equipment Requirements for Safety
CSA C22.2 No. 601-1-M90 Electromedical Equipment,

Warnock Hersey Listed
ANSI S3.39-1987 Aural Acoustic Impedance Admittance (Type 3)
IEC 1027-1991 Aural Acoustic Impedance/Admittance (Type 3)
ANSI S3.6-1989 Audiometers (Type 4)
IEC 645-1 Pure Tone Audiometers (Type 4)

TYMPANOMETRY/REFLEX MODES:

Probe Tone: 226 Hz, ± 3%
Sound Pressure Level: 85.5 dB SPL, ± 2.0 dB,

measured in a 2.0 cm3 coupler

Harmonic Distortion: <5%
Admittance (Compliance) Range: 0 to 1.5 cm

0 to 3.0 cm

NOTE:

1. The range is automatically selected based upon the amplitude
of the compensated (tymp only) tympanogram.

2. The maximum uncompensated (ECV + tympanogram peak)
admittance (compliance) range is 0 to 5.0 cm3.

3. ECV/cavity limits for initiating pressurization is 0.2 to 6.0 cm3.

Compliance Accuracy: ± 0.1 cm3 or ± 5%, whichever is greater

3
3

PNEUMATIC SYSTEM

Pressure Range: +200 to –400 daPa

NOTE:

1. 1 daPa = 1.02 mm H20

2. Pressure sweeps to at least –100 daPa. To save test time,
pressure sweep stops once tympanogram returns to baseline
after –100 daPa.

3. Full pressure sweep for 6 cm3 from sea level to 7000 ft.
altitude with no leak.

Pressure Accuracy: ±10 daPa or ±15%, whichever is greater

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Rate of Sweep: 600 daPa/sec except near tympanogram peak

where sweep rate slows to 200 daPa/sec to provide better
definition of peak compliance.

Direction of Sweep: Positive to negative
Tympanometric Test Time: approximately one second

NOTE:

High compliance tympanograms will take somewhat longer

Gradient: Tympanogram pressure width at 50% of peak

compliance.

ACOUSTIC REFLEX STIMULI:

Frequencies: 500, 1000, 2000, and 4000 Hz
Accuracy: ±3%
Total Harmonic Distortion: <5%
Rise/Fall Time: 5 to 10 msec
Output Levels:

IPSI: 500 and 4000 Hz:80, 90, 100 dB HL

1000 and 2000 Hz: 85, 95, 105 dB HL

NOTE:

1. Ipsi stimuli are time multiplexed with probe tone
(106 msec ON, 53 msec OFF).

2. Stimuli are presented at lowest level first. If there is no
response, the intensity is increased by 10 dB until a
response is detected or the maximum dB HL is reached.

Pressure: Automatically set to pressure at peak compliance with

an offset of –20 daPa.

Reflex Determination: Compliance change of 0.05 cm3 or greater.
Reflex Test Time: 1 to 12 seconds depending upon the number of ipsi

test frequencies selected (four maximum) and intensity required.

Probe LED Indicators:

Steady yellow: occlusion
Blinking green: ready to start testing
Steady green: test in progress
Steady orange: leak

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AUDIOMETRY MODE (Model No. 26230, No. 26230-RS,
No. 26235 and No. 26235-RS only— marked “Version 4”)

Frequencies: 125, 250, 500, 750, 1000, 1500, 2000, 3000, 4000,

6000, 8000 Hz

Accuracy: ± 3%
Total Harmonic Distortion: < 3% (125 to 3000 Hz measured acous-

tically at maximum dB HL; 4000 & 6000 Hz measured electrically)

Intensity Levels: 125 Hz: –10 to 50 dB HL

500 to 6000 Hz: –10 to 90 dB HL

250 and 8000 Hz: –10 to 70 dB HL

NOTE:

An additional +10 dB is available per frequency via the
+10 dB button.

Accuracy: 125 to 4000 Hz ±3 dB

6000 and 8000 Hz ±5 dB

Step Size: 5 dB
Signal-to-Noise Ratio: > 70 dB in 1/3 octave;

less than –10 dB HL for levels less than 60 dB HL

Rise/Fall Time: 20 to 50 msec
Tone Format (tone is normally off until present bar is depressed):

Continuous: steady when present bar is depressed
Pulsed: 2.5/sec (i.e., 200 msec ON, 200 msec OFF)
FM (frequency modulated): 5 Hz, ±5%

TRANSDUCERS

IPSI: Welch Allyn design
Audiometric Headset: Pair TDH-39 earphones with MX41AR

cushions (60 ohms impedance)—Models No. 26230,
No. 26230-RS, No. 26235 and No. 26235-RS only
(marked “Version 4”)

PRINTER

Paper Roll Length: approximately 80 feet (960")
Tests/Roll: Tymp and Reflex = 420 tests or 210 people

Tymp and Reflex plus one audiogram =
230 tests or 115 people

Speed: approximately 1.5 minutes to print three screens

(including audiogram).

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