Welch Allyn SureTemp 679, SureTemp 678 Service manual
SureTemp
Thermo Menu
678 Operation Manual
679 Operation Manual
679V Operation Manual
®
Model 678 & Model 679 Thermometer
Technical Manual
© 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
SureTemp® Model 678/SureTemp® Model 679 i
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
ii Welch-Allyn, Inc.
LIST OF FIGURES
FIGURE 1 - THERMOMETER DIAGRAM..............................................................................1-1
FIGURE 2 - M678 DISPLAY.................................................................................................. 1-3
FIGURE 3 - SYSTEM BLOCK DIAGRAM..............................................................................4-1
FIGURE 4 - PROBE LOGIC CIRCUITRY..............................................................................4-6
FIGURE 5 - PROBE LOGIC DIAGRAM.................................................................................4-6
FIGURE 6 - SELF-TEST /ERROR TABLE.............................................................................5-2
FIGURE 7 - THERMOMETER ASSEMBLY DRAWING....................................................... 5-13
FIGURE 8 - MAIN PCA........................................................................................................5-14
FIGURE 9 - ELECTRONICS ASSEMBLY............................................................................5-15
FIGURE 10 - SCHEMATICS................................................................................................5-17
SureTemp® Model 678/SureTemp® Model 679 iii
W ARRANTY
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
year for the
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.
M678 and one per room M679
M679
from the date of first shipment from Welch Allyn. This warranty
:
and one
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.
iv Welch-Allyn, Inc.
SPECIFICATIONS
Case Dimensions
•
(nominal):
Case Material:
•
Weight (nominal):
•
Input:
•
Display range:
•
Laboratory Accuracy:
•
Clinical Accuracy:
•
Push buttons:
•
Mode Button:
•
Probes:
•
Power Source:
•
Battery Operating Life:
•
2.25 in. x 3 in. x 7 in
5.7 cm x 7.6 cm. x 17.8 cm
ABS Plastic
10.25 ounces with batteries and probe
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’)
28.9o C to 42.2o C (84.0o F to 108.0o F)
± 0.2o F in the Monitor mode and in a water bath
per Welch Allyn document number 90565-000
Meets the ASTM E1112-86 clinical test standard
Mode and Pulse Timer
Selects oF/ oC, Oral, Axillary and Monitor Modes
Interchangeable Oral (also used for Axillary) and
Rectal
Three “AA” Batteries
Approximately 5,000 temperature measurements
(At 72o F ambient temperature)
Display Type:
•
Operating temperature:
•
Storage Temperature:
•
Liquid Crystal Display, 3½ digits plus special icons
16o C to 40o C (60.8 o F-104o F) @ 15% to 95%
RH non-condensing per ASTM E1112-86
-20o C to 50o C (-4o F-120o F) @ 15% to 95%
RH non-condensing per ASTM E1112-86
SureTemp® Model 678/SureTemp® Model 679 v
TERMINOLOGY
Many standard abbreviations are used in this Technical Manual.
Abbreviation Definition
PCB printed circuit board
PCA printed circuit assembly
LCD Liquid Crystal Display
BATT Battery
DMM Digital Multi-Meter
O-Scope Oscilloscope
Component Reference Designators include:
Abbreviation Definition
C capacitor
D diode
E test point
J connector jack
(the board itself)
(the board with all its components)
L inductor
P connector plug
Q transistor
R resistor
S switch
T transformer
U integrated circuit
X crystal, resonator
vi 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
Manual
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:
and this manual assumes an understanding of these operations. This chapter
There are many things that can be done to check operation before the unit is
disassembled. This section will cover these normal operating actions.
User’s
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. Probe cover box 6. Probe Handle
2. Display 7. Probe storage well
3. Timer button (678 only) 8. Probe connector receptacle
4. Mode button 9. Probe cover storage well/ Battery cover
5. Probe cover ejection button
Figure 1 - Thermometer Diagram
SureTemp® Model 678/SureTemp® Model 679 1-1
Technical Manual
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.
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
1-2 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
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
Maintenance
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
the unit is reset. However, resetting the electronics is the
Preventive
section.
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
SureTemp® Model 678/SureTemp® Model 679 1-3
section.
Technical Manual
Probe Warmer Circuit Self Tests
Proper instrument functionality should be verified first as described in the
Reset/Self Tests
section (above) before a probe is installed. With a properly
Instrument
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.
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.
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
Troubleshooting
section.
Battery Life Problems
in the
1-4 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.
If the instrument determines that room temperature is above 33.9°C (93.0°F).
•
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.
SureTemp® Model 678/SureTemp® Model 679 1-5
Technical Manual
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
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.
Timer Problems
in the
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
Problems
1-6 Welch-Allyn, Inc.
section in the
Troubleshooting
section.
Backlight
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
Troubleshooting
the
section.
Temperature Recall Problems
in
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.
SureTemp® Model 678/SureTemp® Model 679 1-7
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