DISMANTLING INSTRUCTIONS
Numbers in the parentheses refer to Fig. 1 on Page S.5.
Remove the pulse lead (34) complete with plastic former (29) and iron
core (30). Remove the fixing strap (47), the terminal insulator (46) and
the rubber grommet (33). Remove the nuts and washers securing the three
point terminal block (39) and lift the block clear. The external rubber ring
(28) can then be removed. Using pliers or other suitable tool remove and
discard the bezel (1) taking care to avoid breaking the glass (2). It is
now possible to remove the glass, sealing washer (3) and slip ring (4).
Remove the pointer (5) using suitable pointer lifters which will not damage
the dial (7). Supporting the dial and movement assembly (10) unscrew the
movement fixing screws (38). Lift clear the complete movement assembly and
unscrew the base plate to movement screws (26) and remove the magnet (11).
If necessary the foam washer (14) can be detached from the pole piece (13).
The remainder of the components can be removed as required.
INSPECTION AND CLEANING
All parts of the tachometer should be checked for wear or damage and
be renewed as necessary. All screws should be checked for tightness. The
movement assembly
(10),
which is available only as a sub-assembly, should
be inspected with care. It is important to check that the hairspring tails
are securely soldered to the tags.
All soldered connections throughout the tachometer should be inspected
for dry joints. If it is necessary to remove components from the printed
circuit board the minimum of heat should be used. Excessive temperature will
cause distortion of the board and damage the electronic components. Finally,
prior to assembly, all parts must be carefully cleaned and any foreign matter
removed using a fine paint brush where necessary.
ASSEMBLY INSTRUCTIONS
ASSEMBLY OF MOVEMENT
Holding the movement by the two side members replace the magnet with
its south pole facing away from the moving coil. Correct assembly of the
magnet, from the polarity point of view, is most important to ensure
satisfactory operation of the tachometer and for this reason the south pole
faces of all magnets are marked on the factory production line with yellow
crayon. If the crayon mark has become erased the south pole of the magnet
can be determined by means of a separate magnet of known polarity.
Alternatively the polarity of the magnet can be determined by using a compass.
Having correctly located the magnet, replace the pole piece (13) and
fit the pole bridge piece (12). It will be observed that the pole bridge
piece is rectangular in shape and if incorrectly fitted will overlap the
front pole piece by 3/16" (4.7mm).
ASSEMBLY OF THE MOVEMENT TO THE BASE BOARD
In a central position secure the foam washer to the rear pole piece,
using Paripan Locking Varnish or a suitable equivalent. Using the base
board to movement fixing screws, dipped in Paripan Locking Varnish or
a
suitable equivalent, secure the base board to the movement. Should any
wires between the base board and movement assembly have been removed
during repair or dismantling re-solder them to the correct terminals.
S.
6
