2 kW scanner RB714A periodic rotation stop

Simrad have examined an RB714 scanner which
periodically would stop rotating, typically after
1-2 hours of operation. They found that the
lower ball bearing for the rotary joint was
positioned in a way it could touch the bottom
of the chassis. Why this could happen is
because of the tolerances of how deep the
machining is done and the uneven surface of
the molding.
The chassis part has been made to the same
tolerances since October last year.
Although there are several hundred units in
operation, they are only aware of some three
units which have this problem. We do therefore
not consider this to be a major issue.
However, in order not to take any chances, a
very thin spacer is now inserted as standard in
all RB714A scanners.
Update of units in stock:
Simrad recommend that all RB714A scanners in
stock, from serial number R016126 and after
are modified with the special spacer, except
for the scanners delivered from Central
Warehouse after 1 September 2005, which
already include the spacer.
Update of units in the field:
Simrad quote: "We do not see that a general update of scanners
in the field is required, but if a scanner is
reported to stop at times, it is recommended
to check the rotating function by tilting the
motor to disengage the gear and turn the
antenna by hand to make sure it runs freely".
If you feel or hear that the rotation is not
perfect it may be due to the machining and
you will need to insert the spacer.
NB! The motor torque of the RB714A is very
low in order to reduce mechanical noise. This
low torque may also result in a rotation stop/
pause when the scanner is in a high dynamic
situation i.e. rough water and high speed.
The scanner will normally re-start by itself.
Conclusion:
When a customer is complaining about his
scanner because it stops rotating periodically,
and the cause can not be related to rough
water or high speed, we kindly ask you to
check the rotating function as mentioned
earlier in this paper.
Please forward results to me for discussion on best plan
of action to have the spacer fitted.

Regards Frank.