Maintenance and Repair
302
7SS52 V4 Manual
C53000-G1176-C182-3
8.4
Repair
Siemens strongly recommends to refrain from repairing units or modules, because
they contain especially selected components, which must be handled according to the
regulations for EED (
E
lectrostatically
E
ndangered
D
evices). Most importantly, special
techniques are required for working with the printed circuit boards, so that the flow-
soldered boards and sensitive components are not damaged.
Therefore, if a defect cannot be eliminated by the operations described in this chapter,
it is recommended to send the complete unit or defective module back to the
manufacturer.
In case it is unavoidable to replace single modules, the EED-regulations have to be
followed (handling of
e
lectrostatically
e
ndangered
d
evices).
Modules fitted in the unit are not endangered.
The module or bay unit must be safely packed for shipping. Shock resistance as per
IEC 60255-21-1 Class 2 and IEC 60255-21-2 Class 1 must be ensured.
If a module or bay unit needs to be replaced, please observe the following:
•
Protective devices in housings or factory-assembled mounting racks are delivered
as complete units and can be replaced as such by units with the same MLFB. Match
the pick-up threshold of the binary inputs to the station conditions.
•
Plug-in modules are normally interchangeable if their ordering numbers are
identical as far as the oblique stroke.
•
Note on ZPS modules the address setting and the order number and on the EAZ
modules and the D-CPU module also the jumper setting of the control voltage.
•
Individual modules of the bay unit cannot be replaced.
After replacement of devices or modules, complete parameterizing of the system may
be required. Details are given in the Chapters 5, page 91 and 6, page 209.
Warning!
Hazardous voltages can be present in the device even after the power supply voltage
has been removed, i.e. capacitors can still be charged.
Caution!
Electrostatic discharges via the components, printed conductors and connection pins
must under all circumstances be avoided by previous contact with earthed metal parts.
This applies in the same way for replacing components in sockets, such as EPROMs
or EEPROMs. Suitable electrostatic protecting packing has to be used for mailing.
www
. ElectricalPartManuals
. com