ST700 GENERAL HANDBOOK
667/HB/27880/000 Page 82 Issue 8
Replace the hinged front plate holding the CPU PCB and, if fitted, the I/O or OTU
PCB.
Replace all the cables to the CPU. Clip the earth lead to the front plate.
Restore power to the ST700.
Note: The new Power/Phase assembly is supplied with a chassis door fitted. It is not
necessary to replace the door when the Phase Drive PCB has failed. The old
Power/Phase assembly should be returned to Siemens Poole with the replacement
door.
6.4.7 Replacement of Manual Panel PCB
First unplug the cable connecting the manual panel to the CPU PCB.
The manual panel is held to the main Cabinet Assembly by a number of screws that
need to be removed. After removing these screws the panel may remain held in
place by the sealing strip. Ease the panel away from the housing, gradually working
from one corner, taking care not to scratch or otherwise damage it.
The replacement panel should be mounted with a new sealing strip to prevent water
ingress. After fitting, reconnect the cable to the CPU PCB.
Where an Internal Manual panel is fitted, it may be removed directly by removal of
the screws holding it to the 19 inch panel; it may be easier to remove the 19 inch
panel from the rack first. No sealing is required on refitting.
6.4.8 Replacement of Expansion I/O or OTU PCB
Removal of the I/O or OTU PCB may be done once the Mains to the ST700 Rack
Assembly has been isolated at the master switch, the 64-way Phase Control ribbon
cable has been disconnected from the CPU and the hinged front plate has been
opened.
Ensure that the replacement PCB has the correct firmware and PLD fitted at the
correct variant and issue. Refer to the Works Order Specification for details.
The I/O or OTU PCB is removed by removal of the screw fixings (4 off) which secure
it to the inside surface of the hinge plate. Ensure all the cables are fully disconnected
before the board is removed, and fully inserted following the replacement of the
board.
6.5 REPLACEMENT OF MAINS POWER SUPPLY UNIT
The spare Mains Power unit is provided as part of the Power/Phase Assembly. It is
not necessary to replace the whole assembly if the power unit has failed, providing
the failure has not damaged other components.
