Disassembly - Siemens SIPROTEC 7SA522 Manual

3 Mounting and Commissioning
Spare Parts
3.1.2.2

Disassembly

Work on the Printed
Circuit Boards
378
Spare parts can be the buffer battery that provides for storage of the data in the
battery-buffered RAM when the voltage supply fails, and the miniature fuse of the in-
ternal power supply. Their spatial arrangement is shown in the figure of the processor
board. The ratings of the fuse are printed on the board next to the fuse itself. When
exchanging the fuse, please observe the hints given in the SIPROTEC
scription in the chapter "Maintenance" and "Corrective Action / Repairs".
Note
It is assumed for the following steps that the device is not operative.
Caution!
Caution when changing jumper settings that affect nominal values of the
device:
As a consequence, the order number (MLFB) and the ratings that are stated on the
nameplate do no longer match the actual device properties.
If changes are necessary under exceptional circumstances, the changes should be
clearly and fully noted on the device. Self-adhesive labels are provided for this which
can be used as supplementary nameplates.
To perform work on the printed circuit boards, such as checking or moving switching
elements or exchanging modules, proceed as follows:
• Prepare your workplace: Prepare a suitable underlay for Electrostatically Sensitive
Devices (ESD). Also the following tools are required:
– screwdriver with a 5 to 6 mm wide tip,
– a crosstip screwdriver for Pz size 1,
– a nut driver with 4.5 mm socket.
• Unfasten the screw-posts of the D-subminiature connector on the back panel at lo-
cation "A". This is not necessary if the device is designed for surface mounting.
• If the device features interfaces next to the interfaces at location "A", the screws
located diagonally to the interfaces must be removed. This is not necessary if the
device is designed for surface mounting.
• Remove the covers on the front panel and loosen the screws which can then be ac-
cessed.
• Remove the front panel and place it carefully to the side.
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4 System De-
7SA522 Manual
C53000-G1176-C155-3