SIRS NAVIGATION LTD
COMPONENT MAINTENANCE MANUAL
TESTING & FAULT ISOLATION
A. General
The contents of this section, identify and recommend solutions to problems
which can occur in service.
NOTE: A complete performance test procedure must be applied to the
compass after adjustment, repair or component replacement, other
than the replacement of the ‘filament lamp’ (240).
The magnetic tests in this section are to be used as an indication of
performance. Accurate magnetic tests can only be applied in an approved
magnetic test facility.
The faults most likely to occur in service are:
(i) Directional
Error.
(ii) Defective
Lighting.
(iii)
Slow Movement of the Compass Card.
(iv)
Fluid Loss/Air Bubble.
(v)
Magnetic Correction Problems.
(i)
Directional
Error.
The compass will indicate an incorrect heading. The causes of directional
error are detailed below.
a) Friction’ between the ‘pivot’ and ‘jewel’ of the ‘compass card assembly’.
(refer to ‘paragraph iii’ of this section).
b) Magnetic error in the ‘compass card’ (130) magnet. (refer to section 7002
paragraph C).
c) Magnetic error in the ‘corrector assembly’ (160) (See ‘para v’ of this
section).
(ii)
Defective
Lighting.
If the compass light is defective, refer to the Troubleshooting chart that
follows, (ref. Fig. 1001).
PAGE 1001
APR 10/03
34-25-21
The document reference is online, please check the correspondence between the online documentation and the printed version.
