Sharp 14VT10X1, Service Manual

Page: 32 / 138

ADJUSTMENT OF THE VCR ELECTRICAL CIRCUITRY
Prior to the adjustment:
In most cases, necessity for electrical circuits will
If the equipment fails electrically, locate a defect or
arise from replacement of mechanical parts
i n c l u d i n g t h e v i d e o h e a d .
defects first of all using instruments. Then repair or
B e f o r e s t a r t i n g
a d j u s t m e n t o f e l e c t r i c a l c i r c u i t s , c h e c k t h a t
r e p l a c e p a r t s a n d m a k e a d j u s t m e n t b y t h e
procedures described below.
m e c h a n i c a l o p e r a t i o n o f t h e e q u i p m e n t i s
When required instruments are not available, do
complete (the mechanism are adjusted completely).
not move controls indiscriminately.
Instruments
l VTVM l Oscilloscope
l DC regulated power supply l Audio generator
ADJUSTMENT OF POWER CIRCUIT
l Colour bar generator l Frequency counter
l Alignment tape Blank video tape (VHS)
l
Test points layout
Figure 2-O.
n
ADJUSTMENT OF POWER CIRCUIT
Adjustment of power circuit
Measuring
instrument
DC voltmeter
Mode
Test point
E-E
C921 LEAD
Control R917
Specification
0.2
( 1 ) C o n n e c t a v o l t m e t e r t o (pin 4 of
connector PA) and ground.
(2) Adjust so that the voltmeter reads
Adjustment of power circuit
Measuring
instrument
I
DC voltmeter
Mode E-E
I
Test point
I
LEAD
I
Control R921
Specification
0.1
( 1 ) C o n n e c t a v o l t m e t e r t o (pin 1 of
connector PA) and ground.
(2) Adjust R921 so that the voltmeter reads
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