Welch Allyn 767 User manual

SureTemp®
Model 767 Thermometer
Technical Manual
Thermo Menu
Operation Manual

Technical Manual
© 1997 by Diatek Instruments, Inc., A Welch Allyn Company. All rights reserved. No part of this manual may be reproduced
or transmitted in any form or by any means, electronic or mechanical, including photocopy, without prior consent in writing
from Welch Allyn. Printed in the USA
SureTemp is a trademark of Welch Allyn, Inc. All rights reserved.

Technical Manual
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TABLE OF CONTENTS
WARRANTY.......................................................................................................................................... 1
SPECIFICATIONS................................................................................................................................. 2
OPERATIONAL CHARACTERISTICS................................................................................................... 2
Introduction ...................................................................................................................................... 2
Basic System Description................................................................................................................. 2
Safety & Warnings ........................................................................................................................... 4
Setup................................................................................................................................................ 4
Changing Probes.............................................................................................................................. 5
Normal Mode.................................................................................................................................... 5
Monitor Mode ................................................................................................................................... 5
Biotech Mode ................................................................................................................................... 5
PREVENTATIVE MAINTENANCE......................................................................................................... 6
Cleaning and Sterilization................................................................................................................. 7
Routine Cleaning................................................................................................................................. 7
ETO Gas Sterilization Procedure......................................................................................................... 7
CALIBRATION TESTING...................................................................................................................... 7
Calibration Key Procedure................................................................................................................ 7
M9600 Procedure............................................................................................................................. 8
THEORY OF OPERATION.................................................................................................................... 8
Technical Overview.......................................................................................................................... 8
Probe Enhancements....................................................................................................................... 8
Probe Switch.................................................................................................................................... 9
Monitor Mode ................................................................................................................................. 10
Normal Mode.................................................................................................................................. 11
Power Supply................................................................................................................................. 11
Microcontroller I/O Assignments..................................................................................................... 12
Memory/IO Input/Output Assignments............................................................................................ 13
IIC Interface to LCD Display Driver................................................................................................. 14
Reset/Self Tests............................................................................................................................. 15
Microprocessor Clock..................................................................................................................... 16
Temperature Measurement and Display......................................................................................... 16
A/D Power Control.......................................................................................................................... 17
Probe Detection.............................................................................................................................. 17
Probe Warming.............................................................................................................................. 17
Liquid Crystal Display..................................................................................................................... 18

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Backlight (Optional)........................................................................................................................ 18
Horn 19
F/C Switching................................................................................................................................. 19
ERROR CODES.................................................................................................................................. 19
TROUBLESHOOTING......................................................................................................................... 21
Equipment Required....................................................................................................................... 21
Terminology ................................................................................................................................... 22
Troubleshooting Table.................................................................................................................... 23
FIELD SERVICEABLE REPAIRS........................................................................................................ 28
FIELD SERVICEABLE PARTS............................................................................................................ 29
THERMOMETER DISASSEMBLY....................................................................................................... 29
THERMOMETER REASSEMBLY........................................................................................................ 34
SUGGESTED SPARE PARTS LIST.................................................................................................... 35
OPTIONS AND ACCESSORIES .........................................................................................................35
TABLE OF FIGURES
FIGURE 1 - THERMOMETER DIAGRAM.............................................................................................. 3
FIGURE 2 - SYSTEM BLOCK DIAGRAM............................................................................................ 10
FIGURE 3 - LCD DISPLAY.................................................................................................................. 15
FIGURE 4 - THERMOMETER ASSEMBLY DRAWING....................................................................... 30
FIGURE 5 - SYSTEM SCHEMATIC .................................................................................................... 32
FIGURE 6 - PRINTED CIRCUIT ASSEMBLY...................................................................................... 33

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WARRANTY
3-YEAR LIMITED WARRANTY ON NEW INSTRUMENTS: Instrumentation purchased new from
Welch Allyn, Inc. (Welch Allyn) is warranted to be free from original defects in material and
workmanship under normal use and service for a period of three years from the date of first shipment
from Welch Allyn. This warranty shall be fulfilled by Welch Allyn or its authorized representative
repairing or replacing at Diatek's discretion, any such defect, free of charge for parts and labor.
Welch Allyn should be notified via telephone of any defective product and the item should be
immediately returned, securely packaged and postage prepaid to Welch Allyn. Loss or damage in
shipment shall be at purchaser's risk.
Welch Allyn will not be responsible for loss associated with the use of any Welch Allyn product that (1)
has had the serial number defaced, (2) has been repaired by anyone other than an authorized Welch
Allyn Service Representative, (3) has been altered, or (4) has been used in a manner other than in
accordance with instructions.
90 DAY LIMITED WARRANTY ON PROBES AND PROBE COVERS:
Welch Allyn warrants probe covers and probes to meet Welch Allyn’s specifications for the Product at
the time of purchase and to be free from original defects in material and workmanship under normal
use and service for a period equal to 90 days from the date of first shipment of such Product to the
customer by or on behalf of Distributor.
THIS WARRANTY IS EXCLUSIVE AND IN LIEU OF ANY IMPLIED WARRANTY OR
MERCHANTABILITY, FITNESS FOR PARTICULAR PURPOSE, OR OTHER WARRANTY OF
QUALITY, WHETHER EXPRESSED OR IMPLIED. WELCH ALLYN WILL NOT BE LIABLE FOR ANY
INCIDENTAL OR CONSEQUENTIAL DAMAGES.
The information in this manual has been carefully reviewed and is believed to be accurate; however,
no responsibility is assumed for inaccuracies. Furthermore, this information does not convey to the
purchaser of Welch Allyn devices any license under the patent rights to the manufacturer.

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SPECIFICATIONS
Case Dimensions: 5.1 inches high x 4.1 inches wide x 4.0 inches deep.
Case Material: ABS Plastic.
Weight: 1.0 lbs
Input: Welch Allyn Thermistor Probe (Oral P/N 02767-000, Rectal P/N 02767-100).
Display range: 28.9oC to 42.2oC (84.0o F to 108.0o F).
Laboratory Accuracy: ± 0.2o F in the Monitor mode and in a water bath per Welch Allyn SOP 90565-000.
Clinical Accuracy: Meets the proposed ASTM clinical test criteria.
Push buttons: Mode button
Probes: Interchangeable Oral, Rectal
Power Source: Model 767 Wall Transformer.
Display Type: Liquid Crystal Display, 3½ digits plus special icons.
Operating temperature: 16oC to 40o C (60.8 o F-104o F) @ 15% to 95% RH non-condensing per ASTM E1112-86.
Storage Temperature: -20oC to 50oC (-4oF-120o F) @ 15% to 95% RH non-condensing per ASTM E1112-86.
OPERATIONAL CHARACTERISTICS
Introduction
The Welch Allyn 767 SureTemp is a wall mounted thermistor thermometer to be used for measuring
patient temperatures ranging from 84 °F to 108 °F (28.9 °C to 42.2 °C). Oral and rectal probes utilize
single-use disposable probe covers which limit cross-contamination. Oral and rectal temperatures are
taken using Normal or Monitor operating modes. Axillary temperatures are taken with an oral probe
with the unit operating in the Monitor mode. In the Normal mode, the thermometer’s microprocessor
“predicts” body temperature in about 4 seconds for oral temperatures and in about 15 seconds for
rectal temperatures. The Monitor mode continuously displays the temperature of the probe which will
reflect the patient’s actual temperature in about 3 minutes and will continue for as long as the probe
remains in place.
Basic System Description
The thermometer system consists of four main components: the external AC power supply, the
thermometer instrument, the probe, and the probe cover.
The M767T Thermometer can use either a Welch Allyn Model 767 domestic (120V 60HZ) or
international (230V 50Hz) Wall Transformer or a Welch Allyn Model 77305 AC Adapter for its external
AC power supply. These power supplies are available from Welch Allyn.
The main instrument’s operation is described below.
The Model 767T is easily connected to the Model 767 Wall Transformer. Two screws are used to
secure the Model 767T to the Model 767 Wall Transformer. The use of a 9’ long probe cord with a
safety latch incorporated into its connector housing ensures that the Model 767T can be safely used
with the Model 767 Wall Transformer without slipping out of its connector.

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The Model 767T probe is similar in appearance to the probe for the M600, M670, and M675; but is
incompatible with any of these instruments. M600, M670, and M675 probe are also incompatible with
the Model 767T instrument.
Welch Allyn’s 767T thermistor based probes can be identified by color combinations as follows:
Handle
Color Top Color Connector Color/Type Model # Probe Type
Fog White Blue Fog White,
Latching M767T Oral
Fog White Red Fog White,
Latching M767T Rectal
The Model 767T instrument’s connector receptacle configuration and size disallows insertion of any
but Model 767T probes.
The probe covers are unchanged from previous models and are compatible for use with all of Welch
Allyn’s thermistor based thermometers.
MODE
1
3
2
4
6
78
9
5
1. Display 6. Probe
2. Probe storage channel 7. Probe handle collar
3. Dual probe cover storage well 8. Ejection button
4. Probe connector receptacle 9. Mode selection button
5. Probe connector receptacle latch
FIGURE 1 - THERMOMETER DIAGRAM

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Safety & Warnings
CAUTION: DISCONNECT THE SYSTEM FROM THE MAINS SUPPLY BEFORE CONNECTING
THE 767 SURETEMP 4 THERMOMETER.
USE THE 767 SURETEMP 4 WITH WELCH ALLYN 3.5V 767 SERIES WALL TRANSFORMER
ONLY.
DO NOT USE IN THE PRESENCE OF FLAMMABLE ANESTHETICS.
Caution: Federal (USA) law restricts this device to sale by or on the order of a physician.
In order to obtain accurate and reliable temperature-taking results and ensure patient safety, it is
important that this booklet be read thoroughly prior to using the instrument. If you have any technical
or clinical questions concerning the thermometer’s use and/or care, please contact our Customer
Service Department at [phone].
• Single-use disposable probe covers, available from Welch Allyn or Diatek, will limit patient cross-
contamination. The use of any other probe cover or the failure to use a probe cover may produce
temperature errors and will invalidate the instrument’s warranty.
• Oral probes (blue ejection button) are to be used for taking oral and axillary temperatures only.
Rectal probes (red ejection button) are to be used for taking rectal temperatures only. The use of
the wrong probe will produce temperature errors.
• The thermometer case is not waterproof; do not drip fluids onto it.
• Do not use this instrument for any purpose other than that specified in this booklet. Doing so will
invalidate the instrument’s warranty.
• Do not use the thermometer if you notice any signs of damage to the probe or instrument.
Contact our Customer Service Department for immediate assistance.
Setup
1. Install supplied Oral probe or optional Rectal probe by inserting the latching plug on the end of
the coiled cord into plug receptacle on the unit. The plug snaps into place and cannot be
removed without depressing the latch. (Figure 1).
2. Insert probe shaft completely into probe storage channel.
3. Turn on the 767 Wall Transformer.
4. (blinks) and (steady) are displayed when an oral probe is installed. When
displayed, the thermometer is characterizing the probe. The display will clear when complete.
This process will take from 10 - 70 seconds.
is displayed when a rectal probe is installed.
5. Remove the probe from the storage channel.
6. Observe the LCD to see that all display segments appear followed by the display of the probe
type OrL = Oral or rEC = Rectal. Replace probe in storage channel.
7. Insert two boxes of disposable probe covers (part number 05031) into the dual storage well.

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Changing Probes
• Depress the latch and unplug the probe connector from the thermometer.
• Remove the probe from the storage channel.
• Repeat steps 1 through 6 in the SETUP section.
Normal Mode
Most temperatures are taken in the Normal (predictive) mode. The thermometer automatically resets
to the Normal mode after the probe is returned to the storage channel.
Note: For Oral probes; if the instrument’s display changes to the probe type display, OrL°F, before
the probe cover is loaded, the display will change to°F(without OrL) briefly upon loading of the probe
cover. The instrument is not ready for the probe to be inserted into the patient’s mouth until the
display returns to OrL°F.
The thermometer will switch to Monitor Mode automatically under the following conditions:
1. If the prediction algorithm has not been activated within 30 seconds of withdrawing the probe
from the probe storage channel.
2. If the instrument determines that room temperature is above 33.9°C (93.0°F).
The thermometer reads the probe temperature immediately upon removal of the probe’s shaft
from the storage channel. If the probe is extracted immediately after taking a temperature; it will
not have had sufficient time to cool to room temperature. This will cause the instrument to detect
a false room temperature higher than actual room temperature.
Monitor Mode
Monitor mode is generally used for long term temperature monitoring, taking axillary temperatures, or
when difficult situations prevent accurate temperatures from being taken in the Normal mode.
When used correctly, the instrument will display the patient’s temperature in about 4 seconds. The
instrument will beep briefly to signal completion of the Normal mode temperature cycle.
If the probe’s shaft is not inserted into the storage channel within 30 seconds of completion of a
Normal mode temperature cycle, the instrument will shut off. Simply replace the probe’s shaft into the
storage channel to prepare for the next temperature.
Note: The instrument will shut off automatically if the probe temperature remains below 28.9°C
(84.0°F) for more than 5 minutes.
Biotech Mode
Biotech mode provides the ability to query the following information:
1. Display test.
2. Software revision.
3. Internal temperature reference measurement to the nearest 1/100 of a degree Fahrenheit.

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4. Probe temperature to the nearest 1/100 of a degree Fahrenheit (98.30 will be displayed as 830).
Biotech Mode is entered by the following steps:
Note: While in the Biotech mode, the leading digit and decimal point are suppressed in order for the
instrument to display temperatures at higher resolution (i.e., 98.3 °F will be displayed as 830).
1. Ensure that a probe has been installed.
2. Depress and hold the Mode button for 7 seconds.
3. Observe that the instrument completes its display test. This is the same display test as initiated
when power is first applied. Each segment of the display is individually lit. Following this, all
segments are lit briefly.
4. The instrument will then momentarily display the software revision with the left half of the probe
shaft icon and the probe cover icon (indicating Biotech Mode). The display should show “r X.X”
where “X.X” is the revision number (i.e., r1.5). You will need to know the revision number when
discussing operation with Welch Allyn customer support.
5. A temperature display of the internal-reference-resistor measurement comes next. This reading is
generated by the instrument reading an internal, precision, fixed resistor as if it were a probe. If all
of the A/D conversion electronics are functioning properly, this measurement will produce a
reading between 678°C (36.78°C) and 689°C (36.89°C), or 820°F (98.20°F) and 840°F (98.40°F),
inclusive. Momentarily depressing the Mode button will always toggle the reading between Celsius
and Fahrenheit regardless of the mode.
6. A display of the probe tip temperature can now be obtained by withdrawing the probe from its
holder. The display will be of the same form as the internal-reference-resistor measurement
display (see above).
Note: If the probe is not removed from the probe holder within 1 minute, the unit will exit from the
Biotech Mode.
7. To exit Biotech Mode at any time, put the probe back into its holder. If the probe was never
removed from its holder, pull it out from its holder and then return it to its holder.
If you cannot enter the Biotech mode, refer to the Biotech Mode Problems section of the
Troubleshooting section.
PREVENTATIVE MAINTENANCE
The following suggested preventative maintenance is recommended to maximize uninterrupted
service on the Model 767 SureTemp 4 Thermometer
Units which are in service on a regular basis should have the following preventative maintenance
performed every 6 months:
1. Visually inspect the thermometer for physical damage which might cause future product failure.
2. Clean the unit per instructions in your Directions for Use manual supplied with the thermometer
and/or per the instructions below.