Welch Allyn SureTemp 767 Technical Manual
  1. Manuals
  2. Brands
  3. Welch Allyn Manuals
  4. Thermometer
  5. 767
  6. Technical manual

Welch Allyn SureTemp 767 Technical Manual

Hide thumbs Also See for SureTemp 767:
Table of Contents

Advertisement

Quick Links

Thermo Menu
Operation Manual
®
SureTemp
Model 767 Thermometer
Technical Manual

Advertisement

Table of Contents
loading
Need help?

Need help?

Do you have a question about the SureTemp 767 and is the answer not in the manual?

Questions and answers

Subscribe to Our Youtube Channel

Related Manuals for Welch Allyn SureTemp 767

Summary of Contents for Welch Allyn SureTemp 767

  • Page 1 Thermo Menu Operation Manual ® SureTemp Model 767 Thermometer Technical Manual...
  • Page 2 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.

  • Page 3: Table Of Contents

    Technical Manual 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......................
  • Page 4 Welch Allyn Model 767T 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......................

  • Page 5: Warranty

    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.

  • Page 6: Specifications

    28.9 o C to 42.2 o C (84.0 o F to 108.0 o F). Laboratory Accuracy: ± 0.2 o 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.

  • Page 7: Figure 1 - Thermometer Diagram

    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 Top Color...

  • Page 8: Safety & Warnings

    Service Department at (800) 854-2904. • 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.

  • Page 9: Changing Probes

    Technical Manual 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.

  • Page 10: Preventative Maintenance

    (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.

  • Page 11: Cleaning And Sterilization

    6. Remove the sterilization packaging. 7. Before applying power, allow the probe and instrument to stabilize to room temperature for at least one hour. 8. Verify proper calibration of the thermometer and probe using the Welch Allyn Model 9600 Calibration Tester. CALIBRATION TESTING Calibration Key Procedure Unplug the probe from the thermometer.

  • Page 12: M9600 Procedure

    The reading on the thermometer must be within the range specified on the 9600. Refer to the M9600 Operation Manual for complete instructions. Note: All Welch Allyn thermometers (thermistor and infrared ear thermometers can be checked in the M9600.) If you are having problems with the use of the M9600, refer to the Troubleshooting section in the M9600 Operation Manual.

  • Page 13: Probe Switch

    Technical Manual Probe Switch The probe switch (S2) is activated by the probe shaft when the probe is installed or removed from its storage channel. Placing the probe into the channel, pulls U1-29 high via R27. When the probe is withdrawn, this line is pulled low.

  • Page 14: Monitor Mode

    Welch Allyn Model 767T FIGURE 2 - SYSTEM BLOCK DIAGRAM Monitor Mode The Monitor mode is selected manually by the Mode button (S1) on the right side of the instrument. This button, when pressed, ties U1-30 low. When this line (*DMODE) is held low for more than two seconds with the probe’s shaft withdrawn from its holder, the thermometer enters Monitor mode.

  • Page 15: Microcontroller I/O Assignments

    Technical Manual Microcontroller I/O Assignments The following table depicts the input/output assignments for the microcontroller, with “active low” signals prefixed with an underscore (refer to schematic and block diagram): MC68HC11D0 Input/Output Assignments Signal Name Port In/Out Pin Number R/_W PD7, R/_W PD6, AS _wake_up _IRQ...

  • Page 16: Memory/Io Input/Output Assignments

    Welch Allyn Model 767T Memory/IO Input/Output Assignments The following table depicts the input/output assignments for the PSD311L peripheral, with “active low” signals prefixed with an underscore (refer to attached schematic and block diagram): PSD311L Peripheral Input/Output Assignments Signal Name Port...

  • Page 17: Iic Interface To Lcd Display Driver

    Technical Manual IIC Interface to LCD Display Driver The display driver utilizes an IIC serial interface. Each write to the display (signals sda and scl) must begin with the following four command bytes followed by up to eight data bytes: 70H (device type), e0H (device select), c8H (device mode), 18H through 26H (LCD driver RAM start address).

  • Page 18: Reset/Self Tests

    Welch Allyn Model 767T • • DRIVER ADDRESS 24 - 25 26 - 27 28 - 29 30 - 31 32 - 33 34 - 35 36 - 37 38 - 39 FIGURE 3 - LCD DISPLAY Reset/Self Tests Upon power-up, the microcontroller and memory/IO chips (U1 and U2) receive a power-up reset signal from the components associated with the reset line (U1-14 and U2-3).

  • Page 19: Microprocessor Clock

    Technical Manual Microprocessor Clock The clock for the processor is generated by X1. This is a single 3 pin ceramic resonator with internal capacitors running at 7.3828 MHz. The microcontroller, U1, drives this component into oscillation by incorporating an internal inverter. Temperature Measurement and Display The thermometer uses probes which incorporate negative temperature coefficient thermistors.

  • Page 20: A/D Power Control

    Welch Allyn Model 767T 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.

  • Page 21: Liquid Crystal Display

    Technical Manual Once a stable temperature is determined a 200 mS test pulse of power is applied to the probe via the warming circuitry. The probe temperature change resulting from this pulse is used to determine parameters needed for the PWM algorithm. This completes the probe characterization process. The warming circuitry consists of Q2, Q4, Q10, R8, R15, R16, R18, R25, R28, C14, C15, C202, D6, L1 and the resistance in the probe connected to J1-B and J1-E.

  • Page 22: Horn

    Welch Allyn Model 767T Whenever anything is being displayed, the microcontroller outputs a high to U4-12. U4 then outputs a low at pin 13, which is sent out to the backlight oscillator on the Display PCA via J2B-5. Vdd is also supplied to the oscillator via J2B-1.
  • Page 23 Technical Manual Error Code Table - Software Version R1.7 and above NUMBER ERROR TYPE DESCRIPTION System Hardware/Software Errors E0.1 NON-RECOVER Internal RAM read/write test failed E0.2 NON-RECOVER Internal ROM check sum failed E0.3 NON-RECOVER CPU instruction error E0.9 NON-RECOVER Fatal Software Errors System Transitory Errors E1.0 TRANSITORY...

  • Page 24: Troubleshooting

    Welch Allyn Model 767T Error Code Table - Software Version R1.6 and below (continued) A/D Converter Errors E2.0 RECOVERABLE Low cal. resistor pulse width error E2.1 RECOVERABLE Hi cal. resistor pulse width error E2.2 RECOVERABLE PTB resistor pulse width error E2.3...

  • Page 25: Terminology

    Technical Manual Terminology Many standard abbreviations are used in this section (and elsewhere): printed circuit board (the board itself) LCD PCB PCB holding the display assembly printed circuit assembly (the board with all its Digital Multi-Meter components) Main PCB large PCB holding the microprocessor O-Scope Oscilloscope Liquid Crystal Display...

  • Page 26: Troubleshooting Table

    Welch Allyn Model 767T Troubleshooting Table SYMPTOM POSSIBLE CAUSE PROCEDURE No operation No power to unit Make sure its power supply is plugged in and turned on. Make sure the power supply is providing between 5.9 and 10 Volts AC. Make sure the power contacts are making contact with the power supply.
  • Page 27 Technical Manual Troubleshooting Table (continued) SYMPTOM POSSIBLE CAUSE PROCEDURE Display Failed component in Check that data and clock signals on U5-1 and U5-2 are problems LCD driver circuit. toggling between 0 and 5 volts immediately after power up or (continued) after pressing and releasing the Mode button.
  • Page 28 Welch Allyn Model 767T Troubleshooting Table (continued) SYMPTOM POSSIBLE CAUSE PROCEDURE No Backlight Broken trace. Check U1-21 and U4-12 for proper signal level (+5V (Backlight is when LCD is on. U4-13 and the cathode of D101 should an Option) be low when the LCD is on. With backlight off, all of the oscillator parts (Q101, Q102, R106, R107, C102 and T1(primary) should be at +5VDC.
  • Page 29 Technical Manual Troubleshooting Table (continued) SYMPTOM POSSIBLE CAUSE PROCEDURE Normal/ Ambient above Causes auto switch to Monitor mode. Monitor 33.9°C (93.0°F) Mode switching problems Switched to Monitor If 30 seconds pass after ready in Normal mode, unit mode before probe switches to Monitor mode.
  • Page 30 Welch Allyn Model 767T Troubleshooting Table (continued) SYMPTOM POSSIBLE CAUSE PROCEDURE Cal Key Defective mode Check proper switch operation. Refer to F/C, Mode, and shows only switch or broken Recall Switch troubleshooting section, above. trace. “°F”. Monitor Probe malfunction Change probe.

  • Page 31: Field Serviceable Repairs

    Some minor changes to the exact calibration point will be caused by changing R20, R21 and R23, but as long as the proper type and tolerance resistors are used (0.1%, supplied by Welch Allyn), the unit will remain within specifications.

  • Page 32: Field Serviceable Parts

    Welch Allyn Model 767T FIELD SERVICEABLE PARTS All parts are serviceable by qualified technicians except for the EEPROM and the Monochip 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.

  • Page 33: Figure 4 - Thermometer Assembly Drawing

    Technical Manual FIGURE 4 - THERMOMETER ASSEMBLY DRAWING...
  • Page 34 Welch Allyn Model 767T Item Part Number Description 20983-1000 PCA, TEMP/DISP/CONN 25211-0000 HOUSING, FRONT 25212-0000 HOUSING, REAR 25213-0000 HOUSING 25214-0000 WINDOW, LCD 25215-0000 PLUG, BP 25219-0000 HOLDER, PROBE 43012-0000 BEAD, FERRITE 58101-000 SWITCH, PROBE 58102-000 HORN, PIEZO 58518-0000 CONNECTOR, ZEBRA...

  • Page 35: Figure 5 - System Schematic

    Technical Manual FIGURE 5 - SYSTEM SCHEMATIC...

  • Page 36: Figure 6 - Printed Circuit Assembly

    Welch Allyn Model 767T FIGURE 6 - PRINTED CIRCUIT ASSEMBLY...

  • Page 37: Thermometer Reassembly

    Technical Manual THERMOMETER REASSEMBLY If the Display PCA has been removed from the Front housing, lay the Front housing on a flat surface. Ensure that the LCD and zebra strips have been installed into the Front housing (the bump on one end of the LCD should be to the right as you look in the back of the Front housing). Then, carefully install the Display PCA into the Front housing, with the display flex-strip (J2) on the left side.

  • Page 38: Suggested Spare Parts List

    Welch Allyn Model 767T SUGGESTED SPARE PARTS LIST PART NO. DESCRIPTION QTY PER 100 UNITS 20991-0000 ASSY, CONNECTOR PCA WITH CABLE & FERRITE BEAD 20992-0000 ASSY, PROBE SWITCH 58102-000 HORN, PIEZO 81054-0000 WASHER, FIBER .187 OD X .089 ID .031 THK...
  • Page 39 7420 Carroll Road, San Diego, California 92121 • (800) 854-2904 • (619) 621-6600 • FAX (619) 621-6610 70841-0000A...

This manual is also suitable for:

Suretemp 767t

Table of Contents