Dismantling The Electronic Compartment - Honeywell 854 ATG Series Instruction Manual

5.4.2 Dismantling the electronic compartment

Note:
Whenever the force transducer and/or motor unit have been removed the force transducer must be
recalibrated (refer to section 5.5).
To remove the various components proceed as follows:
• Switch off the mains and remove the cover from the
electronic compartment.
• Remove the PCB retaining screw (B), slide the locking
latch (A) on the XPU board to the right (refer to figure).
• Remove the XPU board and the SPU II board.
• Disconnect non i.s. wiring from the option board,
and put the board temporarily on the back-plane (still
connected via ground wire and blue i.s. wires).
• Remove the GPS board.
• Remove the PCB hexagon support bar.
• Secure the motor frame with the transport bracket
(refer to section 3.2.4).
• Remove the flat cable connecting the motor block to the
back-plane.
• Disconnect the force transducer cable.
• Remove the two screws holding the force transducer by
lifting it slightly in order to release the span wire from the
force transducer.
If the motor block needs to be removed, first remove the measuring drum (refer to section 5.3.2).
• Disconnect the infra-red connector from the back-plane.
• Remove the circlip from the main shaft.
• Gently remove the motor from its shaft and remove the key.
If the back-plane must be replaced, proceed as follows:
• Disconnect the mains and transmission cabling from the back-plane
• Cut the tie -wraps retaining the wires.
• Unscrew and remove the four screws securing the back-plane frame, then remove the back-plane frame.
Assembly is done in reverse order.
Repair of the 854 printed circuit boards
Field repair of the electronic boards is not advised.
The components that can be replaced in the field are EPROMs and NOVRAM, see section 5.4.3 for updating
software versions. Consult the service department of Honeywell Enraf.
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Figure 5.5 Locking latch
Caution
Maintenance