OHAUS RU-U2 User manual

RU
RU
Service Manual
RU
RU – U2 RU – C2
Edition: January 2010

Service Manual RU OHAUS
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© Ohaus, Inc. 2009
No part of this manual may be reproduced or transmitted in any form or by any means,
electronic or mechanical, including photocopying and recording, for any purpose
without the express written permission of Ohaus, Inc.
U.S. Government Restricted Rights: This documentation is furnished with Restricted
Rights.
OHAUS RESERVES THE RIGHT TO MAKE
REFINEMENTS OR CHANGES WITHOUT NOTICE.

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Content Page
1. PRECAUTIONS ......................................................................................................... 4
2. Specifications RU..................................................................................................... 5
2.1 General Description ............................................................................................5
2.2 Features..............................................................................................................6
2.3 Customer/Vendor Display...................................................................................7
2.4 Weighing Capacity..............................................................................................8
2.5 Tare.....................................................................................................................8
2.6 Memory Specifications........................................................................................8
2.7 Label Printer........................................................................................................8
2.8 Electrical..............................................................................................................9
2.9 Operating & Storage Temperature .....................................................................9
2.10 Major Component Map .....................................................................................10
3. Troubleshooting..................................................................................................... 11
4. Calibration............................................................................................................... 14
5. PC software............................................................................................................. 16
6. Flashing Software .................................................................................................. 17
7. POWER SUPPLY .................................................................................................... 18
8. Main Logic PCB...................................................................................................... 19
9. Load Cell ................................................................................................................. 21
10. Warning Messages............................................................................................. 22
10.1 Error Messages.................................................................................................23
11. Interconnecting Diagram ................................................................................... 25
12. Replace main PCB.............................................................................................. 26
13. Replace switch power........................................................................................ 27
14. Replace display................................................................................................... 28
15. Replace load cell................................................................................................. 29
16. Replace keyboard............................................................................................... 32
17. Replace printer.................................................................................................... 33
18. Replace printer head.......................................................................................... 35
19. Install wireless card............................................................................................ 36
20. Maintenance........................................................................................................ 38
20.1 External Cleaning..............................................................................................38
20.2 Cleaning Printer head .......................................................................................38
20.3 Rezeroing..........................................................................................................39
21. RU License .......................................................................................................... 40
22. Exploded Diagrams............................................................................................ 41
23. Spare parts.......................................................................................................... 50

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1. PRECAUTIONS
READ this manual BEFORE
operating or servicing this
equipment.
FOLLOW these instructions
carefully.
SAVE this manual for future
reference.
DO NOT allow untrained
personnel to operate, clean,
inspect, maintain, service, or
tamper with this equipment.
ALWAYS DISCONNECT this
equipment from the power
source before cleaning or
performing maintenance.
CALL Ohaus for parts,
information, and service.

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2. Specifications RU
2.1 General Description
The Ohaus RU is a digital computing scale with an integrated thermal label printer. RU
is a network scale, which has a database containing the PLU, Extra Text and etc. A
Special PC program is available to download the database from the PC.
The standard RU weighing capacity is 6kg, 15kg, 12kg or 30kg range. This scale
integrates seven-segment displays on each display for weight, tare, unit price and total
price. It also includes a 16 characters display on each side to show item description.
The RU, like all other Ohaus products is designed for maximum durability and reliability
in even the most demanding application environments. The RU is manufactured in one
of Ohaus's ISO 9001 and ISO 14001 certified facilities so you are assured to receive a
high quality product.

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2.2 Features
• 6kg, 12kg, 15kg, 30kg.
(3000e or 3000e dual range or 6000e single range)
• LCD display with LED backlight on both operator side and customer side.
• Four lines of seven-segment numeric display for : 5 digits weight, 5 digits tare, 7 digits
unit price and 7 digits total price. Single line 16-character alphanumeric display for
programming and item description.
• Indicators for zero, net and prepack mode.
• Compliance with H44 3000e, R76 OIML 3000e.
• Tactile feel membrane keyboard and an audible beeper.
• A 142 position preset keyboard (RU-U2) for fast PLU retrieval. (Different type may
have different preset key quantity. RU-C2 has 56.)
• Real time clock and RAM are backed up by a lithium rechargeable battery with at
least 1 month memory retention without external power.
• VOID key for clearing previous transaction from accumulator.
• Computer interface port (Ethernet interface) for use with communication software,
uploading software with special tools and RS232 also can be used for FLASH
software.
• Integrated thermal label printer with 8 dots/mm print head. Supports printing paper
width from 25 to 85mm. Supports EAN and UPC bar coding standards. Various paper
types such as die cut labels, continuous strip labels and continuous thermal paper are
supported.

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2.3 Customer/Vendor Display
There are two displays on the scale, one is on the vendor side and the other is on the
customer side.
These two LCD displays incorporate LED backlight. Both the customer and vendor
displays show 5 digits of weight, 5 digits of tare, 7 digits of unit price and 7 digits of total
price values along with cursors for Zero, Net and Prepack mode. Both the customer
and vendor displays can also show 16 alphanumeric characters for commodity
description, marquee and prompt messages during programming.
The Weight and Total Price display characters are 12mm high by 7.4mm wide. The
Tare and Unit Price display are 10mm high by 6mm wide. The alphanumeric
characters are 7.6mm high and 5mm wide.
Another display option available is the full dot matrix display, which can enable
promotional graphical displays as well as special offers to increase in-store sales.
The Display Legends Definitions are shown in the following Table.
Cursor Definition
NET Indicates a tare has been entered and the weight is net.
ZERO Indicates scale at zero, i.e. within 1/4 increment.
PREPACK Indicates Pre-pack mode has been selected.

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2.4 Weighing Capacity
The RU is available in 3/6kg x 0.001/0.002kg, 6/15kgx0.002/0.005kg, 12kgX0.002kg
and 30kgx0.005kg capacities. The scale is designed to withstand static overloads up to
five times the rated capacity without sustaining permanent damage. A weight greater
than five increments over capacity causes the weight display to "-----" and printing is
inhibited. If the scale is under zero by more than five increments, the weight field will
display dashes "|_____|". When zero can not be captured, the weight field will display
EEEEE.
2.5 Tare
Tare is limited to a maximum of 2/3 full capacity.
2.6 Memory Specifications
The Main Logic PCB contains a rechargeable lithium battery that will retain backup
PLU's and the time/date in the SRAM memory for up to one month. Other data,
including calibration data are retained in the EEPROM which requires no battery for
memory retention.
2.7 Label Printer
Labels can be printed with the built-in thermal label printer. The standard printer uses a
54mm wide, high resolution, 8 dots/mm, thermal Printer head. The printer driver PCB
incorporates a heat detection circuit to ensure the best possible print quality while
eliminating any possibility of overheating the head. Overheating is the major cause of
premature Printer head failure. The print speed and density can be adjusted via
SERVICE MODE to compensate for varying types of labels.
The printer supports standard label sizes ranging from 25mm to 102mm long, and
continuous strip stock or continuous thermal paper. Labels can be loaded in a stripped
or unstripped mode. In stripped mode, the labels automatically peel from the backing

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liner. In the unstripped mode, the label and liner will be delivered. A tear/bar allows
continuous stock to be torn to exact length needed. Print specifications for the thermal
printer are as follows:
PRINTER HEAD TYPE: Thermal Printer head
DOT DENSITY: 8 Dots/mm
PRINT SPEED: Max 125 mm/sec
2.8 Electrical
The RU requires a dedicated grounded 100-240 VAC, 50/60 HZ supply, and draws 0.3
amps (scale/printer versions.) The AC line (including ground) must not be shared with
noise and surge generating equipment such as, electric motors, compressors,
thermostats, fluorescent lights, etc. A line conditioning device is recommended to
provide protection from surges and spikes. The Power supply uses an electronic
overload protection circuit designed to protect the internal electrical components.
Normal supply voltage
100VAC(-10%) … 240VAC(+10%);50/60Hz; 0.5A..
Max.input current 2.2A
Fuse T6.3 A/250V internal.
Degree of polution 2.
Over voltage predicament II
Usable altitude up to 2000m.
Weight 10kg
2.9 Operating & Storage Temperature
Operating Range: -10°C to 40°C, humidity from 5% to 95% non-condensing.
Storage Range: -10°C to 70°C, humidity from 5% to 95% non-condensing.

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2.10 Major Component Map
Ref Description
A Display
B Tower
C Platter supporter
D Printer
E Numeric Keypad
F Preset Keypad
G Power switch
B
A
D
E
F
G
A
A
E
F
D

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3. Troubleshooting
Following is a list of symptoms that could occur, and the recommended action to
correct the problem.
SCALE INOPERATIVE/BLANK DISPLAYS
1. Check AC power at outlet.
2. Check Voltage on Main Logic PCB. If voltages are zero, check Power Supply.
3. If test point voltage is good replace Main Logic PCB.
4. Check Display Cable on Main Logic PCB and Operator Display PCB.
Check Display PCB.
KEYBOARD INOPERATIVE
1. Check keyboard connection on keyboard controller PCB.
2. Check Keyboard controller connection to Main Logic, ensure all connections are
secure.
3. If all connections are secure and keyboard is inoperative:
a) Replace keyboard controller PCB.
b) Check keyboard once again.
c) If Keyboard is still inoperative, replace keyboard.
SCALE WON'T ZERO (DISPLAY "PUT PLATTER ON" or "ZERO NOT CAPTURE")
1. Check platter and spider for obstructions. Turn power off then back on.
2. Recalibrate.
3. Check Load Cell supply voltage.
4. Replace Load Cell.
LOSING PROGRAMMED DATA
1. Check Error Report of Service Mode.
2. Check Main Logic voltage at test points.
3. Replace Main Logic PCB.

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PRINTER WON'T DELIVER LABEL
1. Check printer for obstructions.
2. Check if there is a label which has not been removed.
3. Check Take Label sensor obstructions.
4. Clean Take Label sensor.
5. Test Take label sensor with SENSOR TEST in Service Mode.
6. Check harness from Printer to Main PCB.
7. Check label stepper motor.
8. Replace Main Logic PCB.
INCORRECTLY INDEXES LABELS
1. Check label installation.
2. Check label format and label size.
3. Clean Gap Sensor Lens.
4. Check and clean platen roller, stripper bar, and delivery path using MT cleaning pen.
5. Adjust label Gap Sensor through SENSOR TEST in Service Mode.
6. Replace Gap Sensor Assembly.
7. Replace Main Logic PCB.
LABELS DARK
1. If labels are printedcorrectly, but are excessively dark, check the ENERGY setting in
Service Mode.
2. Check printer head harnesses for loose wires.
LABELS MISSING DOTS
1. If the labels are streaked by lines from top to bottom, replace the printer head.
2. If characters are cut off, check label format programming. If OK, replace printer
head.
LABELS ARE EXCESSIVELY LIGHT/DARK
1. Check Print SPEED and ENERGY setting in Service Mode.
2. Check with other known good label stock.
3. If light print, check and clean printer head resistor line and platen roller.
4. Check printer head harness for loose wires.
5. Check Main Logic PCB voltages. If OK, replace printer head.

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LABEL PRINT IS MOTTLED WITH LIGHT SPOTS
1. Check with other known good label stock.
2. Check and clean printer head resistor line and platen.
3. Replace printer head.
LABELS NOT STRIPPING CORRECTLY
1. Check with other known good label stock, e.g. Nashua.
2. Check label format programming.
3. Check rewind spool for wear.
4. Check Gap Sensor and Take Label Sensor with SENSOR TEST in Service Mode.
LABELS PRINTED EVEN IF ONE IS NOT YET TAKEN
1. Check PAP. END DET. option in Service Mode (Paper End Detection)
2. Check Take Label Sensor.
3. Check Main Logic PCB.
OUT OF LABELS ERROR
1. Make sure labels are threaded through the Gap Sensor.
2. Clean/Check Gap Sensor.
3. Check Gap Sensor through SENSOR TEST in Service mode.
4. Replace Gap Sensor.
5. Replace Main Logic PCB.
CAN'T COMMUNICATE WITH PC
1. Test scale serial port through INTERFACE TEST in Service Mode.
2. Check the connection cable.
3. Check which serial port is used at PC.
4. If using HyperTerminal, check the COM PORT SETUP and set to the following
parameters:
Bit per second: 9600
Data bits: 8
Parity: None
Stop bits: 1
Flow control: None

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4. Calibration
• Open sealing wire; • Screw out sealing screw; • operation：
operation：display：description：
 enter the menu
 enter calibration
QUIET 0-2 ambience condition,
0=quiet; 1= normal;
2=disquiet
 enter to calibrate
PUSH CAL BUTTON
push calibration switch press calibration switch
SELECT GEO 12
(INPUT GEO) input weight GEO (0-31)


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CAPACITY 15
(INPUT CAPACITY) INPUT CAPACITY

INC.0.002/0.005
Select increment（if
necessary）select increment

READ THE ZERO
capture zero
ADD WEIGHT 0.000
(input standard weight value
and put on platter) put standard weight on platter
DONE capture the weight
SHUT DOWN turn off scale and power
on again
NOTE:
IN THE PROCESS IF GIVE THE MESSAGE “ INIT. CELL...”, WHICH INDICATE THE
FAULT CALIBRATION.

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5. PC Software
PLU records and setup data of the RU can be programmed through a PC (Personal
Computer) using the Ohaus program. New scales can be easily set up by using this
program.
Which requires an IBM or compatible PC with Windows 95/NT or higher version
operating system. One serial port or Ethernet port is required. The wiring diagrams
shown in the following figure can be used to make cables from a 25-pin or a 9-pin PC
serial port to the 9-pin connector at the RU. Factory cables are available from RU using
the part numbers shown in the figure.
123848OTC Cable, PC DB9 to RU 10ft/3m
RU DB9-F
TO
9-PIN SERIAL
RS232 PORT
PC
DB9-F
TO 9-PIN SERIAL
RS232 PORT
2
3
5
3
2
5

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6. Flashing Software
The RU Operating System Software is retained in Flash EPROM's on the Main Logic
PCB. The EPROM's can be reprogrammed using a PC and a downloader program
"HyperTerminal". Cables and components are the same as above RS232 cable.
Before downloading the software, turn the RU power OFF. Connect one end of the
cable to the PC's serial port and the other end to the RU serial port.
Power ON the scale.
The scale will display "WAIT FOR HOST……" to wait for PC signal.
Then enter the HyperTerminal, to select right COMM port of the computer.
Then set the data as "baud tare 115200, data bits 8, parity none, stop bits 1, flow
control none".
After come back main interface of the Hyper terminal, to select "send file",select the
scale code and the protocol as "1K Xmodem". Send the file to scale.
The PC screen will display a status menu to show the flashing progress. When the
flashing is completed, the scale will reset automatically. Press any key to exit
HyperTerminal program at the PC.

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7. POWER SUPPLY
Following is a list of symptoms that could occur, and the recommended action to
correct the problem.
Place the Power Switch to the OFF position. Remove the platter, spider, and top cove.
To check the +24VDC output voltage from the Power Supply terminal between the
terminals marked +V and GND, the acceptable output range is +24VDC +/-0.50 VDC.
If the voltage is normal, the Power Supply should be good, and the problem should be
suspected as being in the Main Logic PCB or a component that connects to the Main
Logic PCB.
If the output voltage is zero, check the 120 VAC input voltage. If the correct AC input
voltage is present, but there is no +24 VDC output, replace the Power Supply.
If no voltage is present, check the fuse (240VAC 4A) on the power supply. If the fuse is
OK, check AC input at the Line Cord Jack between the Red wire and Black wire. If the
120VAC is present, suspect a defective power switch. If 120 VAC is not present at the
jack, check the fuse (240VAC 3A) installed in the Line Cord Jack, as shown in the
following Figure. If the fuse is OK, verify voltage is present at the AC wall outlet.
working fuse
backup fuse

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8. Main Logic PCB
The Main Logic PCB receives +24VDC from the Power Supply and uses this to supply
+10VDC and +5VDC to other components. The Main Logic PCB controls all functions
in the unit including the thermal printer. Inputs and Outputs to the Main Logic include
the Label Taken Sensor, Gap Sensor, Printer head, Stepper Motor, Rewind Motor,
Load Cell and etc. The following Figure shows the locations of the various components
and connectors on the Main Logic PCB.
If the voltages are not within the range specified, and the Power Supply voltage is
correct, replace the Main Logic PCB.
NOTE:
WHEN REPLACING THE MAIN LOGIC PCB, THE UNIT MUST BE REFLASHED.

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