Sonavision Ltd.
Aberdeen, Scotland
Issue 6
2392-31-0008
Page 13 of 19
assembly removed from the motor shaft. TAKE GREAT CARE NOT to
damage the slipring wires.
The SLIPRING PCB is held onto the end cap by means of three pan head
screws and this PCB can be removed by extracting these screws. Under the
PCB are two connectors which mate with the wiring looms onto the end cap
glass / metal seals. The connectors can be disconnected by carefully pulling
out the wiring looms and then the board can be removed.
4. Re-assembly of the Hood and End Cap
Re-assembly is a reversal of the disassembly procedure but take note of the
following:
a. Always use a screw sealing compound such as Loctite 242 on all screws
to avoid their working loose in use.
b. When replacing the TRANSDUCER PCB, fit to the shaft such that
approximately a gap of 0.5 to 0.75mm gap is available between the top of
HS1 and the magnet. Also check that the head rotates freely without
fouling any other part.
c. Check that the slipring wires make contact with the sliprings and travel
evenly over the surface as the head rotates. Ensure that they do not slip
off the slipring tracks during rotation. To check for correct flexing of the
wires, the slipring contact point should be approximately 7mm above the
TRANSDUCER PCB before fitting to the motor shaft. If necessary, adjust
to suit.
d. Tighten the TRANSDUCER PCB assembly to the shaft using the M3
socket set screw. Do not over-tighten to avoid stripping the threads and
make sure that the screw contacts the flat on the shaft normal to its
surface.
e. Fit the hood and hood clip. The hood clip is tensioned using a pair of
pincers on the tensioning loop. Tighten as tightly as possible without
damaging the clip to avoid oil leaks.
f. Remove the seal screw from the internal face of the end cap and support
the assembly hood down avoiding compressing the curvature of the hood.
g. Oil filling is best carried out in a vacuum chamber. If one is available, place
the end cap assembly under approximately 20mm of oil in a container and
place in a vacuum chamber. Pull a vacuum of at least 100mBar and leave
until air bubble cease to exit the seal screw hole. Release the vacuum
slowly and then repeat the process. It is important that all air is removed
from the hood to avoid collapse of the hood at depth and / or poor acoustic
performance.
h. If a vacuum chamber is not available, oil filling can be carried out by using
a syringe to inject oil into the seal screw hole. In this case, it is more
difficult to remove all air from the hood and repeated attempts to fill and
then wait for air to rise to the surface should be carried out.
i. Once the hood is full of oil, replace the seal screw tightly and wash off
excess oil from the assembly using methylated spirits or a similar solvent.
Do not use aggressive solvents such as acetone or trichloroethylene.
5. Replacement of the electronic chassis
