SureTemp Plus 678 and 679 Service Manual Rev A

© 1997 by Welch Allyn, Inc. 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 U.S.A. Welch Allyn and SureTemp are trademarks of Welch Allyn, Inc. All rights reserved.

TABLE OF CONTENTS TABLE OF CONTENTS... i LIST OF FIGURES ... iii WARRANTY ...iv SPECIFICATIONS ...v TERMINOLOGY ...vi 1. OPERATIONAL CHARACTERISTICS... 1-1 Basic System Description ... 1-1 Self Tests ... 1-3 Instrument Reset/Self Tests ... 1-3 Display Test ... 1-3 Probe Warmer Circuit Self Tests... 1-4 Battery Life ... 1-4 Normal Mode... 1-5 Monitor Mode ... 1-6 Pulse Timer Mode (Model 678 only) ... 1-6 Backlight (Model 678 only) ... 1-6 F/C Conversion ... 1-7 Temperature Recall... 1-7 Biotech Mode ... 1-7 2. PREVENTIVE MAINTENANCE ... 2-1 Cleaning and Sterilization ... 2-1 Routine Cleaning... 2-1 ETO Gas Sterilization Procedure... 2-1 Battery Removal and Replacement ... 2-2 3. CALIBRATION TESTING ... 3-1 Calibration Key Procedure... 3-1 Model 9600 Calibration Testing Procedure... 3-1

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4. THEORY OF OPERATION ... 4-1 Technical Overview ... 4-1 Probe Enhancements... 4-2 Probe Switch ... 4-2 Normal Mode... 4-2 Power Supply ... 4-3 Low Battery Detection ... 4-3 Microcontroller... 4-3 Reset/Self Tests... 4-4 Microprocessor Clock... 4-4 Temperature Measurement and Display... 4-4 Temperature Measurement A/D Converter... 4-4 Theory of Operation ... 4-4 Circuit Description ... 4-5 Probe Identification Logic ... 4-6 Basic Function... 4-6 Circuit Operation ... 4-7 Probe Warming ( Oral probes only) ... 4-7 Theory of Operation ... 4-7 Circuit Operation ... 4-8 Other Components ... 4-8 Liquid Crystal Display ... 4-8 LCD Backlight (Model 678 Only) ... 4-8 Probe Switch ... 4-9 Mode Button... 4-9 Timer Button (678 Only) ... 4-9 Serial Communications Port ... 4-9 Horn ... 4-9 5. TROUBLESHOOTING... 5-1 Error Codes ... 5-1 Equipment Required... 5-2 Troubleshooting Table... 5-3 Field Serviceable Repairs... 5-8 Field Serviceable Parts... 5-8 Model 678/679 Replacement Parts... 5-9 Replacement Parts-Circuit Board Assemblies ... 5-10 Thermometer Disassembly... 5-12

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Welch-Allyn, Inc.

WARRANTY 3-YEAR LIMITED WARRANTY ON NEW M678 AND ON M679 ONE PER ROOM INSTRUMENTS. 1-YEAR LIMITED WARRANTY ON NEW M679 INSTRUMENT: 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 for the M678 and one per room M679 and one year for the M679 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 Welch Allyn'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. 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 or Diatek devices any license under the patent rights to the manufacturer.

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Welch-Allyn, Inc.

SPECIFICATIONS

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Case Dimensions (nominal):

2.25 in. x 3 in. x 7 in 5.7 cm x 7.6 cm. x 17.8 cm

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Case Material:

ABS Plastic

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Weight (nominal):

10.25 ounces with batteries and probe

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Input:

Welch Allyn Thermistor Probe. P/N 02678-000 (ORAL 4’), P/N 02678-100 (ORAL 9’), 02679-000 (RECTAL 4’), AND 02679 -100 (RECTAL 9’)

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Display range:

28.9o C to 42.2o C (84.0o F to 108.0o F)

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Laboratory Accuracy:

± 0.2o F in the Monitor mode and in a water bath per Welch Allyn document number 90565-000

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Clinical Accuracy:

Meets the ASTM E1112-86 clinical test standard

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Push buttons:

Mode and Pulse Timer

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Mode Button:

Selects oF/ oC, Oral, Axillary and Monitor Modes

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Probes:

Interchangeable Oral (also used for Axillary) and Rectal

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Power Source:

Three “AA” Batteries

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Battery Operating Life:

Approximately 5,000 temperature measurements (At 72o F ambient temperature)

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Display Type:

Liquid Crystal Display, 3½ digits plus special icons

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Operating temperature:

16o C to 40o C (60.8 o F-104o F) @ 15% to 95% RH non-condensing per ASTM E1112-86

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Storage Temperature:

-20o C to 50o C (-4o F-120o F) @ 15% to 95% RH non-condensing per ASTM E1112-86

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TERMINOLOGY Many standard abbreviations are used in this Technical Manual. Abbreviation

Definition

PCB

printed circuit board (the board itself)

PCA

printed circuit assembly (the board with all its components)

LCD

Liquid Crystal Display

BATT

Battery

DMM

Digital Multi-Meter

O-Scope

Oscilloscope

Component Reference Designators include: Abbreviation

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Definition

C

capacitor

D

diode

E

test point

J

connector jack

L

inductor

P

connector plug

Q

transistor

R

resistor

S

switch

T

transformer

U

integrated circuit

X

crystal, resonator

Welch-Allyn, Inc.

1. OPERATIONAL CHARACTERISTICS Note: This manual describes both the Model 678 and the Model 679 thermometers. The bulk of the discussion is equally applicable to both products. Where there are differences, it will be noted as to which instrument the discussion applies. The Welch Allyn Model 678 and 679 Thermometers are the next generation of thermistor based medical grade thermometers providing the accuracy and ease of use of thermistor technology as in the well known Model 675. The Model 678 and Model 679 provide a Normal mode oral temperature in about 4 seconds, significantly faster than the typical 30-40 second average time to temperature in earlier products. Basic end user operation of the Model 678 and Model 679 is covered in the User’s Manual and this manual assumes an understanding of these operations. This chapter will help you determine if the Model 678/679 is functioning properly and, if it is not, refer you to the proper section to isolate the problem. Note: There are many things that can be done to check operation before the unit is disassembled. This section will cover these normal operating actions.

Basic System Description The thermometer system consists of five main components: The batteries, the thermometer instrument, the wall mount, the probe and the probe cover.

1. 2. 3. 4. 5.

Probe cover box Display Timer button (678 only) Mode button Probe cover ejection button

6. 7. 8. 9.

Probe Handle Probe storage well Probe connector receptacle Probe cover storage well/ Battery cover

Figure 1 - Thermometer Diagram

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Batteries

The Model 678 and Model 679 thermometers use three standard alkaline “AA” cells. These batteries are readily available and provide long life for reduced down time. No battery charging is required. Note: The use of Ni-Cad rechargeable batteries is allowed. The nominal cell voltage of 1.2 volts for Ni-Cad (vs. 1.5 volts for alkaline) combined with the lower actual capacity than alkaline will result in a much shorter time between battery charges than alkaline battery life.

Instrument

The main instrument operates very similarly to the Model 675. Basic operation has been kept similar to that of the Model 675 to ease learning and use.

Wall Mount

The wall holder is easily secured to a wall (or rolling stand). An optional locking mechanism with a removable key for securing the instrument is available. Through the use of available long probe cords, the thermometer can be used without removing it from the wall holder.

Probe

The probe is similar to earlier probes. Model 670/675 probes are incompatible with Model 678/Model 679 instruments, but Model 767 and Welch Allyn Vital Signs Monitor probes can be used in Model 678/Model 679 thermometers.

Probe Covers

The probe covers are unchanged from previous models and are compatible across all Welch Allyn and Diatek thermistor based thermometers. Welch Allyn’s thermistor-based probes can be identified by color combinations as indicated in the following table.

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Handle Color

Top Color

Cord Color

Connector Color

Model #

Probe Type

Green

Green

Green or Black

Green

M600

Oral

Red

Red

Green or Black

Green

M600

Rectal

Green

Green

Green

Modular Phone style

M650

Oral

Red

Red

Green

Modular Phone style

M650

Rectal

White

Blue

White

Blue

M670/M675

Oral

White

Red

White

Red

M670/M675

Rectal

White

Blue

White

White with latch

M678/679/767

Oral

White

Red

White

White with latch

M678/679/767

Rectal

Welch-Allyn, Inc.

Operational Characteristics

Self Tests Instrument Reset/Self Tests If a problem is reported with an instrument, it is preferred that the user investigate operation before the unit is reset. However, resetting the electronics is the recommended starting point in the checkout process. The batteries must be removed from the instrument to reset the internal microprocessor electronics. Follow the battery removal instructions in the Preventive Maintenance section. Caution: After battery removal, any remaining charge due to internal capacitance must be discharged to achieve a proper reset. After the batteries are out, press the Mode or Timer button for about 5 seconds. The electronics will now properly reset upon new battery installation. 1. Remove the probe from the probe storage well and unplug the probe connector from the instrument by depressing the locking tab and pulling on the connector body. Do not pull on the cord. 2. While watching the display, install the batteries per the instructions in the Preventive Maintenance section and observe the power up self test. The self test includes several internal microprocessor self tests, instrument electronics tests and the display test. If there are internal electronics problems detected by the self tests, the error “|X|” icon will be displayed and an audible tone will sound. Refer to the Error Codes in the Troubleshooting section for an explanation. Display Test The display test begins with each display segment and icon being individually lit in brief and rapid succession. Immediately after this, all display segments and icons are simultaneously illuminated briefly followed by a display of the software revision in this instrument. The beeper also briefly sounds at the beginning of the test. At the end of the test, the display goes blank.

Figure 2 - M678 Display Note: If a probe is installed during this power up time, the probe type will be displayed as the last item before the display blanks. At this point, there should be no probe connected to the instrument. If there is no display, any missing segments, or no beeper, refer to the Troubleshooting section. ®

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Probe Warmer Circuit Self Tests Proper instrument functionality should be verified first as described in the Instrument Reset/Self Tests section (above) before a probe is installed. With a properly functioning instrument, the probe can be run through the self test. If the instrument is functioning properly and a probe is installed, the instrument will initiate the probe warmer self test during the instrument reset self test and whenever a probe is plugged in. If an instrument has passed the Instrument Reset/Self Tests section, install the probe connector and observe the display of the probe type. For Models 678 and 679, the probe type will display for approximately 2 seconds. •

If the display does not show “OrL” or “Aly” with an Oral/Axillary probe plugged in, or “rEC” with a Rectal probe plugged in, there is a problem with either the probe or the probe connector in the instrument.

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If the display goes blank after the probe type display, the probe has passed its tests and the instrument is ready for use. Do not withdraw the probe during this self test.

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If the display shows the malfunction icon |X|, refer to the Troubleshooting section.

Note: Handle the probe only by the probe handle, not the metal shaft. When removing a probe, disconnect the connector by pressing the locking tab and pulling on the connector body. Do not pull it by the cord. If there are any problems with probe initialization, refer to the Troubleshooting section.

Battery Life Under normal use, battery life is expected to provide approximately 5,000 temperature measurements. This number is based on a 22.2°C (72.0°F) ambient temperature, with the security features turned off. Colder ambient temperatures, excessive security alarms, use of non-alkaline batteries, and other usage patterns can reduce battery life. Instruments are shipped with fresh batteries, but we cannot guarantee full life from the first set of batteries due to potential long storage times between shipping and actual use. Battery life can also be reduced by storage at elevated temperatures. If you are experiencing short battery life, refer to Battery Life Problems in the Troubleshooting section.

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Welch-Allyn, Inc.

Operational Characteristics

Normal Mode After instrument and probe warmer self tests, the system is ready for use. Normal mode operation is the rapid mode of temperature taking. This is the default mode and is automatically selected when the probe is withdrawn from the probe well. 1. Upon withdrawal of the probe from its storage well, every segment on the display will be illuminated. Watch for the display to change from the all segments test to the probe type display; “OrL/Aly” or “rEC”, depending on the probe and algorithm type , followed by °C or °F, whichever is selected. This display might take several seconds to appear. At the same time that the probe type is displayed, a short beep will sound. 2. At this point, load a probe cover and take a temperature. To change between the Oral and the Axillary algorithms; place the instrument in Ready mode as described above, and press the Mode button for approximately two seconds. Observe that the display changes between “Orl” and “Aly” every time the Mode button is pressed for more than two seconds. Note: It is possible that the display will switch from the probe type display to the “walking segments” display and back again several times before the probe is inserted in the mouth. This is acceptable operation and will not adversely effect the temperature taken. The thermometer will automatically switch to Monitor mode under some conditions. These are: •

If the prediction algorithm has not been activated for more than 60 seconds after taking the probe out of the storage well.

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If the instrument determines that room temperature is above 33.9°C (93.0°F).

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If the thermometer is unable to predict an oral temperature after 15 seconds due to improper technique such as excessive probe movement.

With correct use, the patient’s temperature will be displayed in about 4 seconds for Model 678 and for Model 679. The instrument will beep to signal completion of the Normal mode temperature cycle. Note: The thermometer reads the probe temperature immediately upon removal from the storage well. If the probe was just placed into the storage well from a previous temperature and immediately extracted, insufficient time may have passed to allow the probe to cool to room temperature. This will result in the instrument determining room temperature to be higher than actual. This could result in the instrument switching to Monitor mode immediately if it detects room temperature to be above 33.9°C (93.0°F). For best results, the user should wait at least 30 seconds between Normal mode temperatures. If the probe is left out of the storage well after completion of a Normal mode temperature, the unit will shut down after 30 seconds to conserve power. Simply replace the probe in the storage well to prepare for the next temperature.

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Monitor Mode The instrument can be placed in Monitor mode by pressing and holding the Mode switch for two seconds after a predictive (normal) temperature has been taken. This mode will be indicated on the display by a capital M in the bottom right corner. Monitor mode provides a direct readout of the probe temperature. This mode of operation has the ability to provide long term monitoring of a patient’s temperature. Unlike Predictive mode, Monitor mode will follow a temperature as it rises or falls. The typical slow rise in temperature when Monitor mode is used is due mainly to the mouth temperature slowly recovering from placement of the colder (room temperature) probe. The probe itself is actually very fast at rising to the temperature of its surroundings, usually within a few seconds. Because of this slow mouth recovery, the recommended time to wait before recording a Monitor mode oral temperature is 3 minutes. Similarly, the recommended waiting period for an axillary temperature taken in Monitor mode is 5 minutes. Monitor mode is also useful in testing the accuracy of the combined probe/instrument system when the probe can be warmed to a known temperature, as with a Welch Allyn Model 9600 Calibration Tester or in a circulating water bath. Note: The instrument will shut off automatically if the probe temperature remains below 28.9°C (84.0°F) or above 42.2 °C (108.0 °F) for more than 5 minutes. If Monitor mode does not display expected temperatures or exhibits other problems, refer to the Troubleshooting section.

Pulse Timer Mode (Model 678 only) Pulse Timer mode is activated from a Low Power or Recall mode by pressing the Timer button. Whenever the unit enters the Pulse Timer mode, it will emit an audio beep at 0, 15, 30, 45 and 60 seconds. The display will then count up one second at a time, “01”, “02”, ..., “60”. Pulse timer mode will be terminated automatically upon completion of a 60 second count and go back to low-power mode. The pulse timer can be shut off at anytime during the 0-60 count by pressing the Timer button, the Mode button or removing the probe from the probe holder. Connecting a probe will also terminate the pulse timer. If the timer does not work or exhibits other problems, refer to Timer Problems in the Troubleshooting section. Backlight (Model 678 only) The backlight is turned on automatically in any mode except Low Power. Once the backlight is turned on, it will automatically shut off whenever the instrument goes into Low Power mode. The backlight provides a display light for use in dark rooms. The LCD is backlit such that all readings are clearly readable in a darkened room from a distance of 18 inches. If the backlight does not work or is showing other problems refer to the Backlight Problems section in the Troubleshooting section.

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Welch-Allyn, Inc.

Operational Characteristics

F/C Conversion When a final temperature is displayed (in Normal, Recall, or Monitor mode), pressing and releasing the Mode button will toggle the temperature between °F/°C. Note: A recalled temperature will be displayed in whichever scale (°F/°C) is selected at the time of recall. This can also be changed during display. If pressing the Mode button does not change the scale of the displayed temperature, refer to Mode Button Problems in the Troubleshooting section. Temperature Recall Whenever the instrument is in Low Power or Pulse Timer mode, pressing and releasing the Mode button will cause the most recent predicted temperature to be displayed for 5 seconds. An “A”, “O”, or “R” will be displayed near the lower right corner of the LCD, designating Axillary, Oral and Rectal temperatures for the recalled temperature. Pressing the Pulse Timer button will interrupt the temperature recall function. Note: No Monitor temperatures will be saved for recall. When a temperature is recalled, the mode in which it was obtained (axillary, oral or rectal) will be shown independent of the present mode. If the last temperature can not be recalled, refer to Temperature Recall Problems in the Troubleshooting section.

Biotech Mode To enter this special program mode: 1. Place the thermometer in the wall holder. 2. Press and hold the Mode button, and at the same time remove the probe from the probe well. Press the Mode button approximately 2 seconds to move sequentially through the various program categories. Changes within each category can be made by momentarily pressing and releasing the Mode button. Upon entering the Biotech mode, the following features and selections become available. A number is provided in the flag area to indicate which Biotech category is displayed. To exit Biotech mode at any time, insert the probe into the probe well. Replacing the probe into the probe holder returns the unit to normal operation. The Biotech mode will automatically time out after 5 minutes of inactivity.

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If you cannot enter the Biotech mode, refer to Biotech Mode Problems in the Troubleshooting section. Function

Settings

1. Software Version

Observe the display, The display should show “r X.X” where “X.X” is a number such as 2.3. This can be helpful when discussing operation with Welch Allyn customer support. Press the Mode button for more than two seconds to advance to the Default Algorithm.

2. Default Algorithm Oral/Axillary Modes

Three settings are available to set the default predictive algorithm: oral, axillary or last prediction. To change the default algorithm, momentarily press the Mode button to advance to the next algorithm. The instrument will be placed in the selected algorithm after the probe has been returned to the probe well. When replacing the batteries, the power-up setting is the oral predictive algorithm. Press the Mode button for more than two seconds to advance to the Battery Voltage.

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3. Battery Voltage

This section displays the current battery voltage with 10 mV resolution. The battery is considered acceptable if it measures higher than 3.4 volts. New batteries should produce 4.5 volts or more. Each thermometer is factory tested for accuracy down to a supply voltage of 2.9 volts. At 3.2 volts, the low battery indicator (battery icon) will flash. When the battery voltage is 3.0 volts or less, the low battery indicator will display without flashing. Three double beeps are generated, followed by a blank display. At this point temperature taking is disallowed.

4. Predictive Temperature Counter

This section displays the count of the number of predictive temperature actuations that have occurred since last cleared (in 100’s). Replacing the batteries will clear the counter. The power-up setting is 0.

5. Anti-Theft Temperature Counter System (Model 678 only)

The user can select the anti-theft time out based upon a predictive temperature counter that can be set as 0, 25, 50, 100 and 200 (0=disabled). •

The unit will not function when the predictive temperature counter has reached the user set parameter. The unit will display a warning consisting of a digit representing the last 5 counts (i.e. 5,4,...1,) and will display “SEC” on the LCD for five seconds when the probe is returned to the storage channel after the temperature is complete or after 30 seconds with the final temperature displayed.

•

When the unit enters the alarm state, it will double beep for approximately 10 seconds and display “SEC” on the LCD. This function is deactivated at power-up.

Welch-Allyn, Inc.

Operational Characteristics

6. Instant Anti-Theft Audio Alarm System (Model 678 only)

The user can select an anti-theft option that instructs the instrument to beep continuously (beginning after approximately 5 seconds) whenever the unit is removed from the wall holder. •

The user must defeat the Instant Anti-Theft Audio Alarm within 30 seconds after removal from the wall holder by holding the Mode button and removing the probe from the probe well, or by returning the unit to the wall holder.

•

After 30 seconds, the instrument must be returned to the wall holder to silence and reset the Instant Anti-Theft Audio Alarm.

•

Once in the Instant Anti-Theft Audio Alarm state, the instrument will continue the audio alarm until power is exhausted or until the unit is returned to the wall holder.

Note: At power-up, this mode is deactivated. 7. Error Log (Function 5 in the Model 679)

The instrument will save the last 10 error messages that occur and display those messages in a last in first viewed sequence. While in error log, the display reads E x.x. To display the next error, momentarily press the mode button. Note: Battery removal will clear the error log of all error messages.

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2. PREVENTIVE MAINTENANCE The following preventive maintenance is recommended to maximize uninterrupted service with the M678 and M679 SureTemp Thermometers. Units which are in service on a regular basis should have the following preventive 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 the Directions for Use manual supplied with the thermometer and/or per the instructions below. 3. Perform the Power-Up Display test, Startup Display test and Model 9600 Calibration Testing procedure found in the Model 9600 Operation Manual. Units which are stored for an extended period and not used should have the following performed every 12 months: 1. Replace the batteries according to the procedures found in the Directions for Use manual. 2. Perform the Power-Up Display test, Startup Display test and Model 9600 Calibration Testing procedure found in the Model 9600 Operation Manual.

Cleaning and Sterilization Routine Cleaning Clean the exterior of both the Model 678 or Model 679 instrument, the wall mount and the probe as needed. Wipe all surfaces with a clean cloth dampened with warm water and a mild detergent, alcohol, or a nonstaining disinfectant such as Sporicidin Spray 1 2 and Towelettes or MetriSpray cleanser . Care should be taken to not scratch the LCD faceplate. Make sure that the cloth is damp, but not too wet. Note: Do not allow cleaning solution to run inside the instrument. Never immerse the thermometer into the cleaning solution. Never autoclave the thermometer or probe. ETO Gas Sterilization Procedure When no other form of decontamination such as a germicidal wipe is acceptable, a low temperature (not to exceed 48.9°C [120°F]) ETO gas sterilization cycle may be used. Refer to your institution’s standard operating procedure for the length of the cycle.

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Sporicidin is a registered trademark of Sporicidin International (800) 424-3733.

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MetriSpray is a trademark of Metrex Research Corporation (800) 841-1428. ®

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This type of sterilization may cause some hazing of glossy plastic surfaces and should be used only when absolutely necessary. 1. Ensure that the probe is removed from its storage well and disconnected from the instrument. 2. Remove any probe covers from the probe and from the probe cover storage well. 3. Remove the batteries following the instructions in the Battery Removal and Replacement section below.

WARNING: Leaving batteries in the thermometer during the sterilization procedure may present an explosion hazard. 4. Wrap the thermometer in a standard sterilization type packaging such as the Baxter Tower Dualpeel Sterilization Pouch. 5. ETO gas sterilize at a temperature not to exceed 48.9°C (120°F) and aerate. 6. Remove the sterilization packaging. 7. Before installing the batteries and probe, allow the probe and instrument to stabilize to room temperature for at least one hour. 8. Reinstall the batteries (see Battery Removal and Replacement below) and verify a successful self test. 9. Install the probe connector and insert the probe into the storage well to start the probe initialization process. 10. Verify proper calibration of the thermometer and probe using the Welch Allyn Model 9600 Calibration Tester.

Battery Removal and Replacement 1. Using a flat surface, lay the thermometer on its front panel. 2. Remove the PROBE COVER BOX HOLDER on the back of the instrument by pressing with thumb and middle finger on the “dimples” located in the sides of PROBE COVER BOX HOLDER. The batteries are located under the PROBE COVER BOX HOLDER. 3. Remove the batteries by pulling on the ribbon located under them. 4. Press either the Mode or the Timer button for approximately five seconds to discharge the electronics. 5. Install 3 new “AA” batteries according to the battery polarities marked inside the battery compartment. Verify that the thermometer completes self-test, then goes blank. CAUTION: Incorrect battery polarity may result in damage to the thermometer. 6. Reinstall the PROBE COVER BOX HOLDER.

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Welch-Allyn, Inc.

3. CALIBRATION TESTING The Calibration Key provides a convenient means of testing the thermometer.

Calibration Key Procedure 1. Extract the probe and disconnect it from the thermometer. 2. Insert the Calibration Key (part number 01637-000) into the probe connector receptacle on the thermometer and observe the display. The display should read CAL for two seconds, and then go blank. 3. Insert a probe shaft into the probe storage well and remove it to initiate a temperature taking cycle. Wait for the display test and then observe the display. The display must read between 97.1°F and 97.5°F inclusive for the calibration of the instrument to be correct. 4. Remove the Calibration Key and reinstall the probe connector plug. 5. Then install the probe into the probe storage well. Note: This Cal Key test does not test the probe. To do so requires the use of the Welch Allyn Model 9600 Calibration Tester. If the reading from the Cal Key is not within the specified range or you are having other problems with the use of the Cal Key, refer to Cal Key Problems in the Troubleshooting section.

Model 9600 Calibration Testing Procedure The Model 9600 Calibration Tester provides a convenient means of testing the entire thermometer system (instrument and probe). •

The 9600 must be warmed up and stable at one of the two available temperature settings.

•

The thermistor based instrument under test must be in Monitor mode and no probe cover loaded.

The probe is inserted into the small hole in the dry heat well of the 9600 and allowed to settle for a minimum of 2 minutes to the final temperature. The reading on the thermometer must be within the range specified on the 9600. Refer to the Model 9600 Operation Manual for complete instructions. Note: All Welch Allyn and Diatek thermometers (thermistor and infrared ear thermometers) can be checked in the Model 9600. If you are having problems with the use of the Model 9600, refer to the Troubleshooting section in the Model 9600 Operation Manual.

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