Kenwood DP-1100 B Service Manual page 147

5 - 2 - 4 F G m e c h a n i s m
(1) C o n s t r u c t i o n
a) 2 0 pairs of N a n d S pole m a g n e t s are radially installed
u n d e r the disc t u r n t a b l e (Fig. M 1 6 ) . These are unified
as m o t o r a s s ' y (10) for service parts.
b) On t h e other h a n d , a PC b o a r d w i t h radial a n d zig-zag
c i r c u i t patterns is p r o v i d e d , at a slight c l e a r a n c e ( 0 . 2
t o 0 . 7 m m ) f r o m t h e a b o v e a s s ' y . (Fig. M 1 7 )
c) T h e relative position b e t w e e n the a b o v e t w o is s h o w n
in Fig. M 1 8 .
Fig. M 1 6 F G magnet
5. MECHANISM OPERATION
Fig. M 1 8 D i s c motor a s s ' y
(2) Operation
W h e n t h e disc m o t o r rotates, an A C e l e c t r o m o t i v e f o r c e
appears in t h e FG PCB d u e t o the m a g n e t i c field c r e a t e d
by the m a g n e t c o m b i n a t i o n . This f o r c e is t a k e n as the FG
signal t o d e t e c t t h e r o t a t i n g s p e e d of the disc m o t o r .
Fig. M 1 7 F G P C B
, Disc turntable
- F G magnet
FG PCB pattern
Disc motor
D P - 1 1 0 0 B II
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