M A I N T E N A N C E P R A C T I C E S
T A B L E 1 0 2 ( C o n t )
S Y S T E M T R O U B L E S H O O T I N G C H A R T
SYMPTOM PROCEDURE
RESULT P R O B A B L E C A U S E
O R C O R R E C T I V E A C T I O N
4 . H a s h o n o n e o r t w o b a n d s .
O t h e r o p e r a t i v e .
1 . C h e c k b a n d s w i t c h f o r
c o n t i n u i t y a n d p o s i t i v e
operation.
1. Defective interstage
transformers.
A. Bandswitch O. K.
5 . S y s t e m O . K . i n R E C
but inoperative in ADF
except tuning meter
responds.
Defective loop amp. Q1
o r b a l a n c e d m o d u l a t o r
CRl through CR4.
1.
1. Tune in station in REC
Switch to ADF and
p r e s s T E S T s w i t c h .
A . P o i n t e r r o t a t e s .
Defective servo amp-
indicator.
B . P o i n t e r s t a t i o n ¬
ary.
1.
Defective power
oscillator.
2.
6 . E q u i p m e n t t a k e s d e fi n i t e
bearing 180 degrees
reversed.
1 . C h e c k l o o p a n t e n n a
c o n n e c t i o n s t o r - f
resolver.
1 . C o n n e c t i o n s b e t w e e n
r e s o l v e r a n d r e c e i v e r
reversed.
A. Connections
O.K.
1. Change connections.
B. Connections
reversed.
7 . E q u i p m e n t t a k e s d e fi n i t e
b e a r i n g s w i t h a c o n ¬
sistent error.
8 . E q u i p m e n t t a k e s c o r r e c t
b e a r i n g s n e a r 0 a n d 1 8 0
degrees, but readings
become increasingly in¬
a c c u r a t e a s 9 0 a n d 2 7 0
d e g r e e s a r e a p p r o a c h e d .
Loop antenna centerline
not aligned with center-
line of aircraft.
1.
Quadrantal error.
Relocate fixed loop.
See INSTALLATION
MANUAL
1.
9 . I n d i c a t o r p o i n t e r h u n t s
e x c e s s i v e l y o n a l l
bearings.
1. Re-adjust sensitivity
control R25 (where
applicable) in servo
amplifier-indicator
until "hunting" of
i n d i c a t o r p o i n t e r i s
reduced. See Fig¬
ure 309 location of
control (R25).
1. P o o r i n s t a l l a t i o n . S e e
Tab l e 1 03.
A . I n d i c a t o r p o i n t e r
still hunts
excessively.
2.
C h e c k o u t p u t t r a n s i s t o r s
QS'^and Q6 and diode CR3
and CR4 in servo amp-
indicator.
D e f e c t i v e fi l t e r c a p a c i t o r
C9. CIO, Cll, C12 or
C14.
3.
10. Excessive audio distor¬
tion on strong signals.
1. Defective AGC circuit.
Ch e ck AG C A m p Q 9 .
2 . C h e c k d i o d e s C R 5 , C R 7 ,
CR9 and CRIO.
1. Readjust AGC.
A. Distortion
unchanged.
11. Servo amp-indicator
t r a n s i s t o r s f a i l
periodically.
1 . C h e c k s u r g e p r o t e c t o r
CRl in servo amplifier
i n d i c a t o r f o r o p e n c i r c u i t .
2 . C h e c k m o t o r f o r " s h o r t s " .
April 1965
(R e v i se d J a nu a r y 196 8 ) Page 119
To Next Page
Loading...
General