Thermo Menu Operation Manual SureTemp® & SureTemp 4® Model 670 & Model 675 Thermometer Technical Manual
© 1996 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.
Technical Manual TABLE OF CONTENTS WARRANTY .........................................................................................................................................1 SPECIFICATIONS ................................................................................................................................2 OPERATIONAL CHARACTERISTICS ..................................................................................................2 INTRODUCTION ..........................................
Welch Allyn, Inc. Temperature Measurement and Display .......................................................................................... 16 Battery Voltage Reading.................................................................................................................. 17 A/D Power Control ........................................................................................................................... 17 Probe Detection...............................................................
Technical Manual WARRANTY 1-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 one year 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, Inc. SPECIFICATIONS • Case Dimensions (nominal): 6.25 inches long x 3.7 inches wide x 2.4 inches deep. • Case Material: ABS Plastic. • Weight (nominal): 10.5 ounces with batteries. • Input: Welch Allyn Thermistor Probe. • Display range: 28.9o C to 42.2o C (84.0o F to 108.0o F). • Laboratory Accuracy: ± 0.2o F in the Monitor mode and in a water bath per Welch Allyn document number 90565-000. • Clinical Accuracy: Meets the proposed ASTM clinical test criteria.
Technical Manual The basic end user operation of the Model 670 and Model 675 is covered in the User’s Manual and this manual assumes an understanding of these operations. The following sections will help you determine if the Model 670/675 is functioning properly and, if it is not, refer you to the proper section to isolate the problem. There are many things that can be done to check operation before the unit is disassembled. This section will cover these normal operating characteristics.
Welch Allyn, Inc. 1 2 3 4 5 8 6 7 9 10 13 14 11 •F •C NORMAL MONITOR 12 1. 2. 3. 4. 5. 6. 7. Probe cover box Probe Display Backlight/Recall switch Timer switch Display legends Battery access door 8. 9. 10. 11. 12. 13. 14.
Technical Manual While watching the display, install the batteries per the instructions in the 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, an error code (EX.X) will be displayed. Refer to the Error Codes section on page 21 for an explanation.
Welch Allyn, Inc. 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 an error code (such as E5.4), the probe is suspect. Note: Probes are very sensitive to temperature variations and the self tests include thermal tests that can be disturbed by any temperature changes. Therefore it is extremely important to minimize thermal disturbance before and during these tests.
Technical Manual 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. With correct use, the patient’s temperature will be displayed in about 10 seconds for Model 670 and 4 seconds for Model 675. The instrument will beep to signal completion of the Normal mode temperature cycle.
Welch Allyn, Inc. button turns on the backlight only for the duration of the button press and then at the end of a Normal mode temperature, the reading will display with the backlight for 5 seconds. Note: When a temperature is recalled, the mode in which it was obtained (Normal or Monitor) will be shown independent of the present setting of the mode switch. Note: When the instrument is in Monitor mode the last temperature memory is updated every second.
Technical Manual all of the A/D conversion electronics are functioning properly, this resistor will produce a reading between 36.7°C and 37.0°C (98.1°F and 98.6°F) inclusive. 6. Press the Backlight/Recall button once to advance the display to the probe type identification test. At this point, probes can be installed or removed. Oral probes should produce the “OrL” display, while rectal probes should produce the “rEC” display. When no probe is installed, the display is blank (except for the flashing M).
Welch Allyn, Inc. PREVENTATIVE MAINTENANCE The following preventative maintenance is recommended to maximize uninterrupted service on the Model 670 SureTemp and 675 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.
Technical Manual 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 channel 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.
Welch Allyn, Inc. CALIBRATION TESTING Calibration Key Procedure Extract the probe and disconnect it from the thermometer. Set the Normal/Monitor switch to the Monitor position and set the F/C switch to the F position. Insert the Calibration Key into the probe connector receptacle on the thermometer. Insert a probe shaft into the probe storage channel 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.
Technical Manual THEORY OF OPERATION Technical Overview The heart of the Model 670 and Model 675 is comprised of three custom integrated circuits which provide most of the microcontroller and analog circuit functions. All control and display functions are governed by the microcontroller (U2), all analog interfacing to the microcontroller, probe, horn and backlight is provided by U1, and operating parameter data is handled by the EEPROM U3.
Welch Allyn, Inc. Probe Enhancements The Model 670 and Model 675 series thermometers have the capability to detect probe type - oral vs. rectal. This allows the oral temperatures to be as fast as possible (10 seconds in the 670 and 4 seconds in the 675) by using different operating modes based on probe type. Rectal probes give a Normal mode temperature in about 15 seconds for both models.
Technical Manual Normal Mode, Model 675 The Oral probe is pre-warmed using a pulse width modulation (PWM) controller to 33.9°C (93°F) upon extraction from the storage channel. When the probe is first extracted and colder than 33.9°C, the pulse widths are at a maximum percentage ON vs. OFF to warm the probe quickly. When the probe reaches 33.9°C, the pulse widths narrow to a duty cycle just enough to maintain temperature.
Welch Allyn, Inc. When the reset signal is complete, the microprocessor launches a series of self checks which include RAM test, ROM test, EEPROM test, instruction set test, self calibration tests (PTB test, hi cal, low cal), probe warmer circuitry tests, probe test, battery voltage test and ambient temperature test. Any failures here will cause a specific error code to be displayed to assist debugging. Microprocessor Clock The clock for the processor is generated by X1.
Technical Manual the discharge current but constitutes a very small constant DC resistance so it has no effect on results. Its only purpose is for RFI suppression. C3, C10, C11, C12 and C13 are also only for RFI, and ESD purposes. In Monitor mode a calibration cycle, where each of the fixed resistors is measured by the A/D function, is performed once every second. In Normal mode a calibration cycle is performed once at the beginning of the temperature prediction process.
Welch Allyn, Inc. Probe connector installation does not “wake” the instrument up. When the probe shaft is stowed, the probe switch places voltage on U2 pin 23 via R24. This “wakes up” the processor which then reads the RAM flag and sees that the probe logic lines are indicating a probe is connected. This situation triggers a probe characterization routine as described in the Probe Warming section. The probe type is determined by the probe logic lines at J1-B and E. Oral probes pull both lines low.
Technical Manual Once the probe has been brought near 33.9°C (93°F), the pulse widths are reduced to maintain this temperature. This is when the display switches from the all segments display test to “OrL” indicating that the unit is ready for placement in the mouth. Note: Do not confuse this with the displays during probe characterization, where “OrL” is indicating that characterization is in progress with the probe in the holder.
Welch Allyn, Inc. The momentary backlight switch (S4) pulls processor pin 39 low. R19 acts as a pull up to return this line high when not in use. This line is also run to test connector J3 pin 6 to allow automated testing of this function during factory test. The processor active high signal is sent out on U2 pin 52 to U1 pin 12 where it is inverted and buffered. This signal coming out of U1 pin 13 pulls through diode D8 and flex strip J2 pin 21 to the display board mounted oscillator.
Technical Manual Non-recoverable errors are generated from internal test failures that are catastrophic (or from promoted recoverable errors). The error code and any appropriate icon will be displayed along with the “[X]” Instrument Malfunction icon. The only way to continue at this point is to reset the electronics by removing the batteries. NOTE: The error codes E2.1, E2.3, E3.0, E3.1, E3.2 and E4.1 can sometimes be caused by a faulty probe.
Welch Allyn, Inc. Error Code Table (continued) E3.0 E3.1 E3.2 NON-RECOVER RECOVERABLE TRANSITORY E4.0 E4.1 RECOVERABLE RECOVERABLE E5.0 E5.1 E5.2 E5.3 E5.4 E5.5 E5.6 E5.7 RECOVERABLE RECOVERABLE RECOVERABLE TRANSITORY TRANSITORY RECOVERABLE RECOVERABLE RECOVERABLE E6.1 E6.2 E6.3 E6.4 RECOVERABLE RECOVERABLE RECOVERABLE TRANSITORY E9.
Technical Manual Power and ground are available at the end terminals of slide switches S2 or S3.
Welch Allyn, Inc. Troubleshooting Table SYMPTOM POSSIBLE CAUSE PROCEDURE No operation Dead batteries, no batteries, battery missing, battery incorrectly installed Refer to Battery Replacement section on page 11. Check that all batteries are installed in proper direction. Reset electronics (see Instrument Reset/Self Tests section on page 4) Refer to Biotech Mode section on page 8 and enter Biotech mode to measure battery voltage as seen by electronics.
Technical Manual Troubleshooting Table (continued) SYMPTOM POSSIBLE CAUSE PROCEDURE Display problems (continued) Broken/shorted flex strip cable. Check continuity of all 30 lines. Assure continuity with flexing of strip. Check for shorts between adjacent lines at both ends. No beeper sound No Timer function ® Failed component in LCD voltage regulator circuit. Check voltages on U2-6, 7 and 8 for about 3.6, 2.4 and 1.2 volts respectively with LCD active. Cracked LCD.
Welch Allyn, Inc. Troubleshooting Table (continued) SYMPTOM POSSIBLE CAUSE PROCEDURE Timer segment missing. LCD problem. See Display problems section. No Backlight/Recall Defective backlight/Recall switch Check J3-6 for proper switch function. Broken trace. Check U2-39 for proper switch function also J2-21. With backlight off, all of oscillator parts (Q1, Q2, R1, R2, C5 and T1(primary) should be at Vcc. Defective Component Check U1-12 and 13, check D8, Q1, Q2. Unit switched to Monitor mode.
Technical Manual Troubleshooting Table (continued) SYMPTOM POSSIBLE CAUSE PROCEDURE Probe: Wrong type displayed (continued) Incorrect wiring of probe Oral probes should have a short between pins B, E and F. (refer to instrument PCB designators for probe pin definition.) Rectal probes should have a short between pins E and F but open between pins B and E or F. Replace with new probe.
Welch Allyn, Inc. Troubleshooting Table (continued) 28 SYMPTOM POSSIBLE CAUSE PROCEDURE Battery Life Problems Excessive backlight use Backlight draws significant current. Normal battery life calculations assume only 15% backlight usage. Dead cell If cell voltage is down significantly in only one cell, this battery is defective. All batteries are drained at the same rate by the instrument.
Technical Manual Troubleshooting Table (continued) SYMPTOM POSSIBLE CAUSE PROCEDURE Monitor mode temperature reading too high Probe malfunction Change probe or test calibration of entire system (instrument and probe) with the M9600 Calibration Tester. Instrument malfunction. Check calibration with Cal Key. Probe malfunction. Recharacterize probe. (remove completely from instrument and reinstall.) Normal mode temperature reading too low. Or change probe.
Welch Allyn, Inc. FIELD SERVICEABLE REPAIRS Repairs are considered field serviceable if the repair will not alter the calibration or proper operation of the instrument. Recalibration requires a computer-based system and is normally performed at the factory. All probes designed to work with the thermometer are fully interchangeable. All components in the Model 670 and Model 675 except U1 and U3 can be replaced without effecting instrument operation or calibration.
Technical Manual THERMOMETER DISASSEMBLY Please note that if your thermometer is within the warranty period, you should return the unit to an authorized service representative for servicing; failure to do so will invalidate the warranty. WARNING: This instrument contains microelectronic devices which are highly susceptible to damage by static discharge. Use proper handling and grounding techniques while working on the internal electronics. 1. Withdraw the probe from the probe storage channel. 2.
Welch Allyn, Inc.
Technical Manual Item Model 670 Model 675 (if different from Model 670) 20952-100 Description Qty Electronics Assembly 1 1 20952-000 3 25088-001 Case Front 1 4 25089-001 Case Back 1 5 25090-100 Mid-Frame 1 6 25091-001 Battery Door 1 7 25103-000 Window, Display 1 8 53009-000 Battery.
Welch Allyn, Inc.
Technical Manual FIGURE 5 - SYSTEM SCHEMATIC (CONTINUED) ® ® SureTemp Model 670/SureTemp 4 Model 675 35
Welch Allyn, Inc. NOTES: UNLESS OTHERWISE SPECIFIED 1 MAXIMUM LEAD PROTRUSION OF COMPONENT CONTACTS TO BE .030 INCH, AS SHOWN. 2 INSTALL SWITCH CONTACTS (PART OF S4 & S5) WITH LONG AXIS, AS SHOWN. 3 INSTALL CERAMIC RESONATOR (X1) WITH LETTERING FACING S4 & S5 END OF BOARD. 4 SOLDER CAPACITOR (C13) ACROSS TWO LEADS OF Q11, AS SHOWN. 5 INSERT POLARIZING KEY (DIATEK P/N 58514-0000) INTO CONNECTOR (J1) IN POSITION SHOWN AND SECURE WITH LOCTITE ADHESIVE 495.
Technical Manual FRAME DIATEK P/N 25092-000 2 3 4 LCD DIATEK P/N 60011-000 ZEBRA CONNECTOR DIATEK P/N 58112-000 1 LAMP DIATEK P/N 58104-000 TRANFORMER DIATEK P/N 52005-000 BOTTOM VIEW DISPLAY PCA DIATEK P/N 20926-000 2 NOTES: UNLESS OTHERWISE SPECIFIED 1 INSTALL INSULATION TAPE ALONG METAL SURFACE OF TRANSFORMER AS SHOWN. 2 CLEAN CONTACT AREA ON LCD AND PCA WITH ISOPROPYL ALCOHOL. THEN ALLOW TO DRY BEFORE ASSEMBLY. 3 FINGER PROTECTION MUST BE WORN DURING ASSEMBLY OF ELASTOMERIC CONNECTOR.
Welch Allyn, Inc. THERMOMETER REASSEMBLY Note: Most of the screws in the unit are plastic thread rolling screws and do not require excessive tightening which will strip out the case plastic threads. 1. If the electronics assembly has been removed from the mid-frame, solder the battery wires and the horn wires to the main PCA, then slide the main PCA into the two retaining tabs near the center of the mid frame and insert the top of the main PCA under the two plastic tabs towards the top of the mid-fame.
Technical Manual SUGGESTED SPARE PARTS LIST Welch Allyn Part No.
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