Welch Allyn Service Manual Universal Charger

711 Charger

Service Manual

711 UNIVERSAL DESK CHARGER

711380

Rev. D

Welch Allyn Medical Division 4341 State Street Road P.O. Box 220 Skaneateles Falls, NY 13153-0220 Copyright 2001

P art N o

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D escri pti on New Release of Uni versal C harger S ervi ce Manual

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D ate 10/09/01

A pproved DK

711380

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5-43926

11/09/01

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Update per E C N

5-44417

03/12/02

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5-44590

05/06/02

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Drawings and/or illustrations and/or part numbers contained in this document are for reference purposes only. For current revisions call the Welch Allyn Customer Service phone number listed in Section 1 page 3.

SERVICE MANUAL 711380 REV. D

WELCH ALLYN UNIVERSAL DESK CHARGER i

Contents

PAGE

Section 1: General Information 1.1 About the Universal Desk Charger ............................................................................... 1 1.2 Block Diagram ............................................................................................................. 1 1.3 Hardware Electrical Specifications ............................................ ...................................... 2 1.4 Help Information ............................................................................................................ 3 1.5 Product Number Structure ............................................................................................. 3 1.6 Safety Warnings ........................................................................................................... 4 1.7 Approvals .................................................................................................................... 4 Section 2: Service 2.1 Incoming Inspection/Checklist ..................................................................................... 5 2.2 Required Tools............................................................................................................. 5 2.3 Incoming Operational Test ........................................................................................... 5 Section 3: Troubleshooting 3.1 Functional Tests/ Initial Diagnostic Steps ..................................................................... 6 Section 4: Repair and Disassembly 4.1.1 Base Housing Removal/Installation ............................................................................ 7 4.1.2 Printed Circuit Board Replacement ............................................................................ 7 4.1.3 Fuse Replacement .................................................................................................... 8

Appendix A: Theory of Operation..............................................................................................9

Appendix B: Assembly Drawing..............................................................................................13

Appendix C: Electrical Schematic..........................................................................................14

ii WELCH ALLYN UNIVERSAL DESK CHARGER

SERVICE MANUAL 711380 REV. D

The universal desk charger electrical circuitry is designed to provide a safe (if not optimal) trickle charge profile for all Welch Allyn handles. It is intended to replace the 71110 Desk Charger. However, the major improvements over the 71110 that directly affect the electrical design are: 1. It is intended to operate from an AC power source from 100V to 275V. Along with a standard IEC connector, this will be an international unit. Performance tests show that the charger will operate down to 90V with a single handle receiving a full charge rate (65 mA), and two handles receiving >45 mA. This exceeds our present 71110 handle which provides 20 30 mA under the same conditions. 2. It is intentionally designed to charge handle / battery combinations that range from 2.5V to 5.5V end-of-charge voltages. Given the present high / low line and high / low battery voltage combinations, the 71110 charger varies its charge current from 20 mA to 80 mA. The universal desk charger is designed to vary by less than 10% under these conditions (typically less than 2%). 3. The universal desk charger provides charge indicator LEDs as well as power on indicator LED(s).

1.1 About the 711 Universal Charger

IMPORTANT: for a complete description on the function and use of the 711 Universal Charger, as well as user safety warnings, cautions, and warranty information, read and understand the 711 Universal Charger Operators Manual part number 711371 (English). Other languages are available.

Charging Well #1

1.2 Block Diagram

AMBER LED (on when current is active)

Current Limit P O W E R I N P U T

Voltage Limit

Output

Charging Well #2

AMBER LED (on when current is active) POWER ON LED Current Limit Voltage Limit Output

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WELCH ALLYN UNIVERSAL DESK CHARGER 1

1.3 Hardware Electrical Specifications

1.3.1 Absolute Maximum RatingsInput Voltage Range: 100VACRMS to 240VACRMS, 50Hz or 60HZ. 275VACRMS (limited by LM317T max voltage spec and transformer design) It is only guaranteed to maintain SELF internal voltages up to 240V, which is its highest rated input. 0V Open Circuit Voltage (Output may be dragged below zero volts if input voltage is less than the peak input voltage) 0 mA to +100 mA (internally limited to 80 mA for short circuit) 5 - 35 Degrees Celsius *, 10% - 90% Relative Humidity Storage Temperature: -20 - +50 Degrees Celsius *, 10% - 90% Relative Humidity

Peak Input Voltage:

Output Voltage:

Output Current:

Operating Temperature:

* This may not be a suitable range for the batteries under charge. 1.3.2 Operating Conditions Output Voltage: Current Limit: Power Consumption C opy rig ht D ATE 1-9-01 D ATE 3/15 /01

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W elch AllynTHESE DRAWINGS AND SPECIFICATIONS ARE THE PROPERTY OF WELCH ALLYN, INC. AND SHALL NOT BE REPRODUCED, OR COPIED, OR USED AS A BASIS FOR SALE OR MANUFACTURE OF EQUIPMENT OR DEVICES WITHOUT WRITTEN PERMISSION. U niv e rs al C ha rger P C B DWG NO 711118 Sheet 1 of 1 R ev X4

D ATE TITLE Size B

T hursd ay, M arch 15, 2 001

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