Honeywell BENDIX/KING KAP 140 Maintenance Manual page 75

4.1 GENERAL
The Rem ot e Ter m inal I nt er f ace is an im por t ant r esour ce f or t r oubleshoot ing pr oblem s involving
t he KAP 140 syst em. A descript ion of t he problem as viewed f r om t he c ockpit t oget her wit h t he
logged er r or s accessible v ia t he RTI will help t o nar r ow t he f ocus of t r oubleshoot ing. The t im e t hat
t he problem occurred s hould be c orrelat ed wit h t he power cycle t ime in t he error log. A m ore
det ailed descript ion of t he error codes is cont ained in sect ion V. Some syst em f ault s can lead t o
m ult iple er r or c odes being logged. I n t hese inst ances, t he f ir s t er r or logged is usually t he m ost
signif icant . I t s hould also be k ept in m ind t hat only t he f ir s t occur r ence of an er r or code is logged
within a power cycle.
The f ollowing s ect ion describes how t o t r oubleshoot a syst em wit h problems t hat do not generat e
an error code; these are primarily related to system performance. The subsequent sections aid
in the troubleshooting of systems with logged errors by describing the various interfaces to the
KAP 140 syst em as seen t hrough t he RTI in diagnost ic m ode (see
Screens, and its sub--sections for more information on accessing diagnostic mode). Use of this
information with the wiring harness diagrams and a multimeter should allow diagnosis of most
system problems.
4.2 PERFORMANCE PROBLEMS
The following table assumes there are no logged error codes to assist in troubleshooting the
system. If an error code has been stored, attempt to resolve the associated problem before using
the following table.
Symptom
Autopilot indicates engage-
ment on FCC, but does not
drive servos.
Autopilot won't engage
pitch modes.
Autopilot won't engage any
modes.
All pitch modes "porpoise"
or have poor tracking be-
havior.
Revision 2, Dec/ 2002
CS: 15574F02. I DU
BENDIX/KING
KAP 140
SECTION IV
TROUBLESHOOTING
Possible Cause(s)
CWS switch stuck active.
If "P" LED on, pitch servo may
be invalid or FCC acceleration
monitor may be active.
AP DISC switch pressed or
stuck active (Both "P" and "R"
LEDs on).
Roll servo invalid ("R" LED
on).
Turn Coordinator invalid
(dashes in mode annunci-
ations).
Install strap mismatch (Mode
annunciations dashed with "P"
and "R" LEDs.)
Pitch servo bridle cable below
minimum allowed tension.
sect ion 3. 3. 2, Diagnost ic M ode
Checks to Perform
Check CWS switch in diagnostics.
Check servo validity and acceleration
monitor outputs in diagnostics.
Check diagnostics for proper switch
operation.
Check roll servo and interconnecting
harness.
Check Turn Coordinator for flag in
view. Replace T.C.
Check harness strap code in diagnos-
tics and compare with STC data.
Check and adjust bridle cable tension
to certified value.
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