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AUDIO CIRCUIT
2 . 5
Note: U n less otherwise specified, a l l test points and adjustments are located on the A U D I O board.
No.
Item
Check Point
Audio B ias
1
TP3 1 ,
Level
TP32 ( G N D )
2
Audio PB
AU D IO OUT R28
Level
TP53
3
R EC F M
Level
A U D I O OUT R40
4
E-E Level
Level
F D P
5
I nd icator
( Level Ind.)
-
&
Adjustment
Signal
Mode
Parts
R9
• N mode
( B I AS ADJ)
• SP mode
• No sig na l
• R EC
(PB L EV E L
• SP and E P mode
ADJ)
• S-V H S mode
RSO
• SP mode
( F M R E C
• R E C then P B
ADJ)
• No signal
• ALC: O F F
[ E -E L EV E L • R E C mode
• AU D I O O U T to
( L ) ]
H i - F i
- - - - - - - - -
R 4 1
[ E -E LEV E L
( R ) ]
• AU D I O O U T to
R 7 3
[ L EV E L IND
H i-Fi
• E-E (Stop) mode
( L) ]
• LE V E L
I N D I CATOR
SW: ON
- - - - - - -
R74
[ LE V E L I N D
( R ) ]
Description
1 . Connect a m i l livoltmeter between TP31 and TP32.
2. Set for R EC mode without signa l .
3. Adjust R9 for 4.4 mVrms.
1 . Connect an oscil loscope to A U D I O O UT.
2. Supply an audio signal (-8 d Bs/1 k Hz) to A U D I O
IN and record together with a video signal, then
p lay back.
3. Adjust R 28 so that the audio output level d u ring
-
playback becomes
6 ± 1 dBs at SP mode
dBs at EP mode) .
1 . Record in the SP mode, without an audio sig na l ,
then play back.
2 . Adjust R80 for 70 mVp-p ± 5 m V F M audio play
back voltage.
1 . Supply a 1 k Hz, -8 d Bs aud io signa l t o AU D I O I N
and a V I D E O signal to V I D EO I N .
2. Set H i- F i R EC level controls to detent positio n .
I n the R EC mode, adjust R40 t o obta i n -6 ± 0.o
d Bs at A U D I O OUT.
- - - - - - - - - - - - - - - - - - - - - - - - - - - -
3. I n t h e same manner, adjust R 4 1 for t h e R ( C H 2 )
channel.
Note : Perform the level ind icator adjustment after
completing the E-E level adjustment (section
2 . 5 . 4).
1 . Supply a 1 k Hz, -8 d Bs audio signal AU D I O I N .
2. Set H� EC level controls to detent position.
. · l1Hh e E-E (STOP) mode, adjust R73 to the point
where the F D P level indicators show 0 d B .
- - - - - - - - - - - - - - - - - - - - - - - - - - - - -
3. I n the same manner, adjust R74 for the R (CH2)
channe l .
(-
6 ± 2
2-9
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