Vaisala FD12P - Manual (Page 126)

User's Guide _______________________________________________________________________
126 _____________________________________________________ M210296en-A
Removing and Replacing
This section describes in detail how to remove and replace the optical
units, the FDT12B Transmitter, FDR12 Receiver, and the Rain
Detector DRD12. You can remove the units when you suspect that
malfunction of the FD12P is caused by faults in the optical units or the
rain detector.
Removing and Replacing Optical Units
WARNING The equipment contains dangerous voltage of 230 VAC.
CAUTION Servicing the equipment must be performed by qualified personnel.
To remove the unit, do the following:
1. Remove the cover at either end of the crossarm by loosening the
four screws holding the cover. Use the Allen key for removing
the screws.
2. Remove the black, round flange that covers the optical unit by
pulling the screw in the middle of the flange. See Figure 33 on
page 127.
3. Loosen the three-hexagon socket locking bolts with the 5-mm,
T-handle Allen key until the optical unit is loose.
4. Disconnect the ribbon cable connector from the unit. Take note
of the position of the optical unit by looking from the lens side.
5. Pull the receiver/transmitter unit carefully out of the hood tube.
If a thin metal piece comes out when removing the unit, set it
back to the tube end. The purpose of the metal piece is to hold
the unit in the right place.
Inspect the condition of the FDT12B and FDR12 optical units
visually. The circuit board test points of the FDT12B and FDR12 units
are described in Appendix C on page 151.