
2
METTLER TOLEDO Service Manual PBA426 / PBA426x 09/09Order number 72230074
Congratulations on choosing the quality and precision
of METTLER TOLEDO. Proper use according to these
instructions and regular calibration and maintenance by
our factory-trained service team ensure dependable and
accurate operation, protecting your investment. Contact
us about a ServiceXXL agreement tailored to your needs
and budget.
We invite you to register your product at
www.mt.com/productregistration
so we can contact you about enhancements, updates
and important notifications concerning your METTLER
TOLEDO product.
Service XXL

General Information ..................................................4
Information for Operation in Ex area .........................5
Spare Parts ..............................................................7
PBA426(x)-A.../QA ....................................................7
PBA426(x)-BB.../B.../QB ............................................9
Repair ....................................................................11
Safety precautions ....................................................11
Replacing the load cell .............................................11
Replacing absorber rubber ........................................ 13
Settings .................................................................14
Setting corner load and overload limits .......................14
Technical Data and Tolerances .................................16
Technical data .......................................................16
Calibration error tables .............................................17
Information about capacity and preload ......................18
Contents
1
2
3
3.1
3.2
4
4.1
4.2
4.3
5
5.1
6
6.1
6.2
6.3
3
METTLER TOLEDO Service Manual PBA426 / PBA426x09/09 Order number 72230074

4
METTLER TOLEDO Service Manual PBA426 / PBA426x 09/09Order number 72230074
General Information
1 General Information
This service manual contains instructions for the repair and
maintenance work of the PBA426(x) weighing platform.
All repair and maintenance work is to be performed by authorized Mettler-Toledo Service Technicians.
It is assumed that the reader is familiar with the operation of
the device and can refer to the relevant operating instructions
when necessary.
The service concept has been designed so that defective parts
can be replaced using a few standard tools and simple aids.
Working with the service manual
The exploded view drawings are provided as a guide for assembling and disassembling work and for identifying the order
numbers for spare parts.
When ordering spare parts, please use the information given
in the spare parts lists. The item numbers in the first column
“Item” correspond to those on the corresponding exploded view
drawing.
PBA426(x)-... analog weighing platforms
PBA426(x)-... analog weighing platforms can be connected to
analog METTLER TOLEDO weighing terminals.
Analog-digital-signal conversion takes place within the terminal. All scale and country specific parameters are stored in the
terminal.

5
METTLER TOLEDO Service Manual PBA426 / PBA426x09/09 Order number 72230074
2 Information for Operation in Ex area
The explosion-protected PBA426x... weighing platforms
are approved for operation in ATEX Zone 1/21 and FM I.S.
Class I, II, III Div. 1 areas.
There is an increased risk of injury and damage when
the explosion protected weighing platforms are used in a
potentially explosive atmosphere.
Special care must be taken when working in such hazardous areas.
Ex approval
▲
▲
▲
▲
▲
No modifications may be made to the terminal and no
repair work may be performed on the modules. Any
weighing platform or system modules that are used
must comply with the specifications contained in the
installation instructions. Non-compliant equipment
jeopardises the intrinisc safety of the system, cancels
the Ex approval and renders any warranty or product
liability claims null and void.
Peripheral devices (operational terminals) not Ex
approved may only be used in a safe area and may
not exceed the maximum supply voltage or the maximum voltage of the weighing cells.
The safety of the weighing system is only guaranteed
when the system is operated, installed and maintained
in accordance with the respective instructions.
Also comply with the following:
- the instructions for the system modules
- the regulations and standards in the respective country
- the applicable statutory requierments for electrical
equipment installed in hazardous atmospheres in
the respective country
- all instructions related to safety iissued by the owner
Before start-up and following service work, check the
explosion protected weighing system for the proper
condition of all safety-related parts.

6
METTLER TOLEDO Service Manual PBA426 / PBA426x 09/09Order number 72230074
General Information
Operation
▲
▲
▲
Installation / Maintenance
▲
▲
▲
▲
▲
Service
▲
▲
▲
Competence
Prevent the build-up of static electricity. Always wear suitable working
clothes when operating or performing service work in an hazardous
area.
Do not use protective hoods.
Avoid causing damage to the weighing platforms.
Installation and maintenance work may be carried out on the weighing
platform in the hazardous zone, providing the following conditions
are fulfilled:
- the owner issued a permit (“spark permit” or “fire permits”)
- the area has been rendered safe and the owner’s safety coordinator
has confirmed that there is no danger
- the necessary tools and any requiered protective clothing are pro vided (danger of the build-up of static electricity)
The certification papers (certificates, manufacturer’s declaration) must
be present.
Lay cables in such a way that they are protected from damage.
Only route cables into the housing of the system modules via the
earthing cable gland or METTLER TOLEDO plug and ensure proper
seating of the seals.
Always disconnect the system from the power supply before commencing maintenance work. Where certain inspections, tests or adjustments
require the system to remain connected to the power supply, this work
must be performed with particular care.
Service technicians must have attended a product-specific course of
training for hazardous-duty equipment.
Service work should be performed outside hazardous zones whereever
possible. Service work includes dismanteling an Ex unit inside the
hazardous zone and moving it into the safe zone.
Only use parts or modules s pecified in the spare parts list as replacement. Do not separate connectors until the weighing system has been
deenergised.
The weighing platform may only be installed, maintained and repaired
by authorised METTLER TOLEDO service personnel.