Welch Allyn 4802D User manual

Welch Allyn Pediatric/Infant Scale with USB
Service Manual
Model 4802D –Pediatric/Infant Scale
For Serial Numbers Beginning with: U1072 only

© 2018 Welch Allyn. All rights are reserved. To support the intended use of the product described in this
publication, the purchaser of the product is permitted to copy this publication, for internal distribution only,
from the media provided by Welch Allyn. No other use, reproduction, or distribution of this publication, or any
part of it, is permitted without written permission from Welch Allyn. Welch Allyn assumes no responsibility for
any injury to anyone, or for any illegal or improper use of the product, that may result from failure to use this
product in accordance with the instructions, cautions, warnings, or statement of intended use published in this
manual.
Software in this product is Copyright 2018 Welch Allyn or its vendors. All rights are reserved. The
software is protected by United States of America copyright laws and international treaty provisions
applicable worldwide. Under such laws, the licensee is entitled to use the copy of the software incorporated
with this instrument as intended in the operation of the product in which it is embedded. The software may not
be copied, decompiled, reverse-engineered, disassembled, or otherwise reduced to human-perceivable form.
This is not a sale of the software or any copy of the software; all right, title, and ownership of the software
remain with Welch Allyn or its vendors.
For information about any Welch Allyn product, contact your local Welch Allyn representative:
http://www.welchallyn.com/en/other/contact-us.html
DIR 80022693 Ver. A
Revision date: 2018-05
Welch Allyn, Inc.
4341 State Street Road
Skaneateles Falls, NY 13153 USA
www.welchallyn.com
Customer Support
Placing orders, checking on pricing, billing, or repairs
[e-mail]
1.800.535.6663, Option 2, 1, 5
9am - 5pm EST
Mon - Fri

CONTENTS
Introduction ..................................................................................................................................................4
Intended use .............................................................................................................................................4
Indications for use.....................................................................................................................................4
Intended clinical care environments.........................................................................................................4
Symbols.....................................................................................................................................................5
Safety ............................................................................................................................................................7
About warnings and cautions ...................................................................................................................7
General warnings and cautions ................................................................................................................ 8
Electrostatic discharge (ESD) ....................................................................................................................9
Overview .......................................................................................................................................................9
Purpose and scope....................................................................................................................................9
Technical support services......................................................................................................................10
Warranty Service.....................................................................................................................................10
Non-warranty service..............................................................................................................................11
Returning products .................................................................................................................................11
Recommended service intervals.................................................................................................................12
Battery replacement...............................................................................................................................13
Scale setup ..................................................................................................................................................13
Enter Setup Mode...................................................................................................................................14
Enter Service Mode.................................................................................................................................15
Factory Mode..........................................................................................................................................16
Calibration of Scale .................................................................................................................................19
USB Details..............................................................................................................................................20
Disassembly and repair...............................................................................................................................21
Required tools:........................................................................................................................................22
Connector types......................................................................................................................................22
Cart Disassembly.....................................................................................................................................23
Scale Disassembly ...................................................................................................................................32
Troubleshooting..........................................................................................................................................54
Scale Troubleshooting.............................................................................................................................54

4
Symptoms and Solutions ........................................................................................................................55
Appendix .....................................................................................................................................................56
Shipping Packing Materials .....................................................................................................................56
Scale Full Exploded View.........................................................................................................................57
Fastener Reference (NOT TO SCALE) ......................................................................................................61
Introduction
Intended use
The Welch Allyn Pediatric/Infant Scale is intended to be used by clinicians for weighing
patients from 0.35 oz. to 44 lbs. (10 g to 20 kg) and measuring patients up to 32 inches
(81 cm), depending on the size of the scale cradle.
Indications for use
The Welch Allyn Pediatric/Infant Scale is used by clinicians to weigh and measure the
length of neonate and pediatric patients.
Pediatric scales can make contact with a patient’s head, neck, back, arms, legs, and side.
Contact duration is intended to be limited to less than 30 seconds.
Intended clinical care environments
The Welch Allyn Pediatric/Infant Scales are intended to be used in the following clinical care
environments:
Hospitals
Ambulatory care centers
Physicians' offices
Other professional medical facilities

5
Symbols

6

7
Safety
About warnings and cautions
Caution statements can appear on the Welch Allyn Pediatric Scales, the packaging, the
shipping container, or in this Service manual.
The Welch Allyn Pediatric Scales are safe for patients and trained clinicians when used in
accordance with the instructions and caution statements presented in this Service manual.
Before using the device, you must familiarize yourself with all cautions, with the steps to
power up the device, and with the sections of this Service manual that pertain to your
use of the device. In addition to reviewing the general cautions presented in the next
section, you must also review the more specific cautions that appear throughout the
manual in conjunction with setup/startup, operation, and maintenance tasks. No additional training is
required.
•Failure to understand and observe any warning statement in this manual could lead
to patient injury or illness.
•Failure to understand and observe any caution statement in this manual could lead to
damage to the equipment or other property, or loss of patient data.

8
General warnings and cautions

9
Electrostatic discharge (ESD)
Electrostatic discharge is a sudden current flowing from a charged object to another
object or to ground. Electrostatic charges can accumulate on common items such as
foam drinking cups, cellophane tape, synthetic clothing, untreated foam packaging
material, and untreated plastic bags and work folders, to name only a few.
Electronic components and assemblies, if not properly protected against ESD, can be
permanently damaged or destroyed when near or in contact with electrostatically
charged objects. When you handle components or assemblies that are not in protective
bags and you are not sure whether they are static-sensitive, assume that they are static sensitive
and handle them accordingly.
•Perform all service procedures in a static-protected environment. Always use
techniques and equipment designed to protect personnel and equipment from
electrostatic discharge.
•Remove static-sensitive components and assemblies from their static-shielding bags
only at static-safe workstations—a properly grounded table and grounded floor mat—
and only when you are wearing a grounded wrist strap (with a resistor of at least 1
megaohm in series) or other grounding device.
•Use only grounded tools when inserting, adjusting, or removing static-sensitive
components and assemblies.
•Remove or insert static-sensitive components and assemblies only with monitor
power turned off.
•Insert and seal static-sensitive components and assemblies into their original static shielding
bags before removing them from static-protected areas.
•Always test your ground strap, bench mat, conductive work surface, and ground
cord before removing components and assemblies from their protective bags and
before beginning any disassembly or assembly procedures.
Overview
Purpose and scope
This service manual is a reference for periodic preventive maintenance and corrective service procedures
for the Welch Allyn Pediatric Scales. It is intended for use only by trained and qualified service personnel.
Corrective service is supported to the level of field-replaceable units. These include circuit-board
assemblies and some subassemblies, and other parts.

10
Find instructions for functional testing and performance verification in the Calibration section in this
manual.
This manual applies only to this device. For servicing of any other product, see the service manual for the
specific device.
Service work not described in this manual must be performed by qualified service
personnel at the factory or at an authorized Welch Allyn service center.
Technical support services
If you have a problem with the device that you cannot resolve, call the Welch Allyn Technical Support
Center nearest you for assistance. A representative will assist you in troubleshooting the problem and will
make every effort to solve the problem over the phone, potentially avoiding an unnecessary return.
Technical support is available 9am-5pm EST.
Welch Allyn offers the following technical support services:
•Telephone support
•Replacement service parts
•Product service
For information on any of these services, go to this site: http://www.welchallyn.com/en/service-
support.html.
Warranty Service
Welch Allyn will warranty the weight scale to be free of defects in material and workmanship and to
perform in accordance with manufacturer specifications for the period of one year from the date of retail
purchase.
The warranty period shall start on the date of purchase. The date of purchase is:
1. The invoiced ship date if the device was purchased directly from Welch Allyn
2. The date specified during product registration
3. The date of purchase of the product from a Welch Allyn authorized distributor as documented
from a receipt from said distributor

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This warranty does NOT cover damages caused by misuse or abuse, including but not limited to:
Failure caused by unauthorized repairs or modifications
Damage caused by shock or dropping during transportation
Damage caused by improper use of the power supply
Failure caused by improper operation not consistent with the instructions stated in
this Service Manual
Should this device require maintenance (or replacement at our option) under warranty, contact your local
Welch Allyn representative: http://www.welchallyn.com/en/service-support.html.
Non-warranty service
Welch Allyn Product Service Centers and Authorized Service Providers support non-warranty
repairs. Contact any Welch Allyn regional service center for pricing and service options.
Welch Allyn offers modular repair parts for sale to support non-warranty service. This
service must be performed only by qualified end-user biomedical/clinical engineers using
this service manual.
Returning products
When returning a product to Welch Allyn for service, ensure that you have the following information:
a. Product name, model number, and serial number. This information may be found on the
product and serial number labels.
b. A complete return shipping address.
c. A contact name and phone number.
d. Any special shipping instructions.
e. A purchase-order number or credit-card number if the product is not covered by a
warranty.
f. A full description of the problem or service request.
1. Contact Welch Allyn and request a RMA number.
Note: Welch Allyn does not accept returned products without an RMA.
2. Ship the device to Welch Allyn, observing these packing guidelines:
•Packaging - If you are returning a scale to a Welch Allyn Repair facility please ensure you
use proper packing materials. Contact Welch Allyn for details and part numbers for materials
if needed.
•Remove from the device the battery, power cords, and other ancillary products and
equipment, except those items that might be associated with the problem.
•Dispose of damaged or leaking batteries in an environmentally safe manner consistent with
local regulations.
3. Clean the device
Note: To ensure safe receipt of your device by the service center and to expedite processing and return
of the device to you, thoroughly clean all residue from the device before you ship it to Welch Allyn. For
cleaning requirements, see the Cleaning instruction in the Directions for Use.
Welch Allyn thoroughly cleans all returned devices on receipt, but any device that cannot be adequately
cleaned cannot be repaired.

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4. Write the Welch Allyn RMA number with the Welch Allyn address on the outside of the shipping
carton.
Recommended service intervals
To confirm that the device is functioning within the design specifications, perform periodic service as
indicated below. Customers can perform the basic functional verification and calibration procedures
referenced below by following the instructions in this manual.
Perform the following preventive maintenance quarterly to keep your scale in working order, or as
required based on usage or per your facility maintenance schedule, whichever comes first.
1. Have your service department check the calibration annually or as required. Calibration
instructions are provided in the scale service manual.
2. Inspect the cradle for cracks or loose mounting hardware. Replace or repair as necessary.
3. Inspect the scale’s enclosure for damage or loose or missing hardware. Replace or repair as
necessary.
4. Inspect the power adapter cable for abrasions or other sign of wear.
5. Do not expose the scale to excessive water or moisture.
6. Do not store the scale where heavy objects can be placed on it.
7. Replace the batteries annually or as required.
8. When storing the scale, remove the batteries from the battery area. Batteries can corrode over a
period of time. Make sure to check the batteries before putting the scale back into use.
9. Do not service or perform any maintenance while the scale is in use with a patient.

13
Battery replacement
Scale setup
You can customize the scale to best suit your needs using the Custom Modes.
The custom modes on the scale are Setup, Service, Factory, Calibration.
1. Press and hold ZERO and REWEIGH while pressing the power button to enter Custom mode.
2. Key in different PIN to access the mode.
Some menu items include editors. These can be interacted with using the following keys: (e.g. Show
‘0000’ as initial 4 digits PIN):
REWEIGH: Increment the selected character. If the current selected character is “9”, it shall
wrap to “0” when the “Reweigh” button is pressed.
RECALL: Decrement the selected character. If the current selected character is “0”, it shall wrap
to “9” when the “Recall” button is pressed.
LB/KG: Move to the next character/enter.
Keying through the menu with the LB/KG key will show the option, then the current setting for that
option. To change a setting select the current setting for the desired option and use the REWEIGH
key to increment or move to the next setting option, or the RECALL key to decrement or move to

14
the previous setting option. Set the selected option and move to the next setting with the LB/KG
key.
Enter Setup Mode
Device will enter setup mode by entering PIN 9821.
The scale will cycle through these parameters by pressing LB/KG key. Some of these options may be
turned off or on through the Factory Mode
SOFt displays the software version.
dAtE displays the software release date in US date format (MM.DD.YY)
SCALE displays the scale model.
AutOFF* displays the number of seconds before the scale turns off when operating on battery
power. The Cont value prevents the scale from turning off automatically.
ACCont* allows the user to configure the scale to be continuously on if AC power is connected.
This overrides the “AutOff” option.
rES allows the user to configure the resolution the scale will display weights at to the following
options:
0.001 kilograms
0.002 kilograms
0.005 kilograms (Default)
0.010 kilograms
UnitS* allows the user to configure the units the scale will be able to use in typical display mode.
Note: Do not change the scale units if you have purchased the kilogram-only option
UI Display Light ON
KILOS*
This option displays weight in kilograms (0.000). Default is ON
POUNDS and OUNCES*
This option displays weight in pounds and ounces (0 pounds 0.0 ounces).
Default is ON
POUNDS*
This option displays weight in pounds (0.000). Default is ON
OUNCES*
This option displays weight in ounces (0.00). Default is ON
bEEPEr* allows the user to configure the external sound. The default is On.
rEcALL allows the user to configure whether the scale can be powered on in recall mode. If set
to off, then Recall key will not operate.
USb* allows the user to send weight data to the computer. ON is to enable usb data transfer
option, OFF is to disable usb data transfer option.

15
Prtunt* allows the user to configure which unit (pounds or kilograms) will be used in the send
data function when the scale is connected to a computer or a Welch Allyn device.
Press REWEIGH or RECALL to switch between the following options:
PrtOPt* Press REWEIGH or RECALL to switch between the following options:
Set-UP This option is displayed when you have cycled through all the options. Press and hold the
power button to power down the scale
Power off scale to exit Set-up Mode
Enter Service Mode
Device will enter service mode by entering PIN 4351.
The scale will cycle through these parameters by pressing LB/KG key.
n¯vv (Mvv) displays the current mV/V reading on the scale.
A-d displays the current weight. ‘Zero’ may be pressed to perform a user zero.
tESt displays a LED test sequence.
Displays a LED test sequence for numbers from 0, 1, 2, ----, 9 for one cycle with long beep
and all annunciators On
Displays a LED test sequence for numbers from 0., 1., 2., ----., 9. for one cycle with long beep
and all annunciators OFF
Sequences continue one after other till user presses LB/KG to move to the next menu item.
PR-OnS displays the number of power ons.
PC-rC displays the number of power ons using the recall key.
COUntS displays the number of times a weight has been acquired.
rEcntS displays the number of times the reweigh key has been pressed.
rECLLS displays the number of times the scale has recalled the prior weight.

16
bn¯iS (BMIs) displays the number of times of the Height/BMI key has been pressed.
OFFS displays the number of times the scale has manually been powered off.
PrintS displays the number of dockets that have been printed from the scale.
SEndS displays the number of the SendData key has been pressed.
SEtUPS displays the number of times the setup menu has been entered into.
SErvES displays the number of times the service menu has been entered into.
CALS displays the number of times the scale has been span calibrated.
Menu will restart to SrvicE menu title when you have cycled through all the options.
Power off scale to exit Service Mode
Factory Mode
Device will enter factory mode by entering PIN 0294.
The scale will cycle through these parameters by pressing LB/KG key.
Functn
AdC.CFG gives the user the option of connecting to the measurement board via the display
board. If yes is pressed, this option will be enabled until the user progresses from the “_____”
screen.
SOFt displays the software version.
dAtE displays the software release date in US date format (MM.DD.YY)
SCALE displays the scale model.
AutOFF* allows the user to configure the time in seconds until the scale powers off.
ACCont* allows the user to configure the scale to be continuously on if AC power is connected.
This overrides the AutOFF option.
FCt.UNt allows the user to configure the scale so that the units (display and print) cannot be
changed from “Set-Up” menu. (“ON” - the units cannot be changed in Setup mode)
UnitS* allows the user to configure the units the scale will be able to use in typical display mode.
Note: If all units are set to Off, the scale defaults to KILOS.
UI Display Light ON
KILOS*
This option displays weight in kilograms (0.000). Default is ON

17
POUNDS and OUNCES*
This option displays weight in pounds and ounces (0 pounds 0.0 ounces).
Default is ON
POUNDS*
This option displays weight in pounds (0.000). Default is ON
OUNCES*
This option displays weight in ounces (0.00). Default is ON
bEEPEr* allows the user to configure the external buzzer. The default is ON.
rEcALL allows the user to configure whether the scale can be powered on in recall mode. If set
to off, then Recall key will not operate.
USb* allows the user to send weight data to the computer. ON is to enable usb data transfer
option, OFF is to disable usb data transfer option.
PrntEr allows the user to send weight data to the built-in-printer. ON is to enable printer option,
OFF is to disable printer option. Printer option is not available to this device and turning on the
option will not change functionality
Prtunt* allows the user to configure which unit (pounds or kilograms) will be used in the send
data function when the scale is connected to a computer or a Welch Allyn device.
Press REWEIGH or RECALL to switch between the following options:
Printing is not available on this unit, changing this setting will not change functionality.
PrtOPt* Press REWEIGH or RECALL to switch between the following options:
Menu will restart to FACtrY menu title when you have cycled through all the options.
Power off scale to exit Service Mode

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Default Factory Settings
Test Setting
4802 Standard(lb/Kg) Display
4802 Kg Only Display
Factory
Func
SOFt
U x.x.x
dAtE
xx.xx.xx
SCALE
4802
AutOFF
90
ACCont
On
FCt.UNt
OFF
UnitS
KG LED (On)
LB OZ LEDs (On)
LB LED (On)
OZ (On)
KG LED (On)
LB OZ LEDs (Off)
LB LED (Off)
OZ (Off)
bEEPEr
On
rEcALL
On
USb
On
PrntEr
Off
Prtunt
Kilos Led (On)
Pounds Ounces LEDs (On)
Pounds LED (On)
Ounces (On)
Kilos Led (On)
Pounds Ounces LEDs (Off)
Pounds LED (Off)
Ounces (Off)
PrtOPt
PnlPrt

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Calibration of Scale
Your scale has been carefully calibrated at the factory. This calibration involves matching and tuning of the load cells
and readout electronics. The scale calibration should be checked annually. Only use calibrated, certified scale test
weights for this purpose. Traction or physical therapy weights are NOT acceptable since their actual weight can
often be in error as much as +/-10%. Calibration weights may be purchased from WELCH ALLYN or a local scale
dealer. An alternative to calibration weights is the weight comparison method. This requires a known accurate,
calibrated scale. A fixed weight is “weighed” on the calibrated scale then the same weight is placed on the scale for
comparison.
TEST CALIBRATION WEIGHTS ARE AVAILABLE FROM WELCH ALLYN.
TWO (2) 10 KILOGRAM TEST WEIGHTS ARE RECOMMENDED.
ORDER PART NO. 20022W. (10 KG TEST WEIGHTS)
If only "pound" test weights are available conversion is as follows:
1.0 Pound = 0.454 Kilograms
5.0 Pounds = 2.268 Kilograms
10.0 Pounds = 4.536 Kilograms
20.0 Pounds = 9.072 Kilograms
25.0 Pounds = 11.34 Kilograms
Large changes in calibration often indicate a damaged load cell or faulty readout component. It is generally
recommended that if calibration is necessary for your scale it should be returned to the factory. Calibration
procedure follows for those situations where it is not desirable. Calibration should not be attempted by those not
having the proper tools or knowledge of electronic systems and their attendant shock hazards.
Calibration Procedure
Enter the calibration mode by following exactly the procedure outlined below:
1. Press ZERO, REWEIGH and Power together to enter Custom mode.
2. Device will enter calibration mode by entering PIN 8933.
The scale will cycle through these parameters by pressing LB/KG key.
3. n¯vv (Mvv) shows the current mV/V on the scale (identical to the option in service mode).
4. ZEr0 is to do zero calibration, press LB/KG key to enter options, press the REWEIGH key to go to
the next option
a. No: Do nothing.
b. Yes: Zero calibrate the scale using the weight currently on the scale.
i. Place the cradle on the scale and make sure it is properly seated. Press the
LB/KG key to begin calibration.
ii. Screen will show ZErO and a number while the calibration is in process and
dONE when the calibration is complete.
c. Defult: Zero calibrate the scale for 0kg = 0mV/V.
5. SPAN is do span calibration, press REWEIGH key for the options
a. No: Do nothing.

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b. Yes: Span calibrate the scale with the user-entered weight and the weight currently on
the scale.
i. Place the calibration weight in the center of the cradle and press the LB/KG key
to begin calibration.
ii. The screen will show US for lbs, press the RECALL key to change to
n¯EtriC(MEtriC) for kilograms. Press the LB/KG key to select units for calibration.
iii. Enter the calibration weight being used. The default for lbs is 40.000 and the
default for kg is 20.000. The REWEIGH key increments and the RECALL key
decrements the selected digit. The LB/KG key moves to the next digit and starts
the calibration after the last digit.
iv. Screen will show SPAN and a number while the calibration is in process and
dONE when the calibration is complete
c. Defult: Span calibrate the scale with the capacity and mV/V taken from the scale type
table.
6. The follow error messages may show:
Error Message
Meaning
ER ZR0
Reading is outside the scale type’s acceptable mV/V range.
ER ZR1
Calibration message failed to send.
ER ZR2
There was an error while waiting for the scale to calibrate.
ER ZR3
The calibration did not save.
ER OL
The span weight was greater than the capacity weight of the
scale.
ER SP1
The span weight was outside the acceptable span margin for
the given mV/V reading.
ER SP2
Calibration weight message failed to send.
ER SP3
Does not currently exist.
ER SP4
Calibration weight message failed to send.
ER SP5
There was an error while waiting for the scale to calibrate.
This can occur if the user presses the Zero key while
calibrating, or if the measurement board has an internal
error.
ER SP6
The calibration did not save.
If an error occurs, press the LB/KG key to exit back to the Calibration options. Retry the calibration.
If the error continues see the Disassembly and repair and Troubleshooting sections to identify.
USB Details
For detailed help and information regarding the data output capabilities, consult Welch Allyn for details.