End Plate Removal And Refitting - Loma IQ2 Service Manual

END PLATE REMOVAL AND REFITTING

The end plate located on the search head case is designed to be removable to
allow access to the electronic boards located inside.
There are no user replaceable parts inside, however if the plate is removed then
the following instructions should be followed.
Incorrect fitting of the plate may result in either water ingress or random
triggering of the detector due to loops of indeterminate electrical resistance
"Eddy Current Loops".
A diagram showing a typical end plate is given in
section.
WARNING
SAFETY - HEAVY End plates can be very heavy, great care must
be taken when removing or refitting the plate.
Removal
1. Loosen and remove all the plate retaining bolts except the top centre bolt with the "O"
ring seal washer.
2. With the end plate securely supported to prevent falling vertically downwards remove the
final bolt, the plate will then lift away from the case. Ensure all bolts, insulating and "O"
ring seal washers are retained.
Refitting
1. Align the plate with the fixing holes, ensuring the insulating/water tight gasket edge is
visible around the full circumference of the case. Replace only the top centre bolt
together with its "O" ring seal washer to secure and prevent the plate falling. Do not fully
tighten this bolt as it is removed later to allow an insulation continuity test to be carried
out.
2. Locate and partially tighten all the remaining bolts and their insulating bushes, slight
movement of the plate facilitates easier bolt alignment. The longest length bolts are used
on the vertical sides.
3. Tighten all bolts to a torque setting of 4 Newton metres (3 pounds feet) in a clockwise
rotation with the exception of the bolt with the "O" ring seal.
4. Using the DMM set on the 2K ohm range or equivalent measure the resistance between
the end plate and the case, this should be > than 250 ohms.
5. Replace the centre bolt and seal washer and tighten to correct torque.
6. The presence of the end plate has a large effect on the normal balance value setting of
your search head. It is therefore advised that a "Balance" check be carried out to ensure
the balance value is within specification. Information can be found in the
in the "Functional testing" section of this manual.
page 2
Module 8023
Maintenance
Figure 5 in this
on page 15
"Balance"
on
6-14