Technics RS-B11W Service Manual page 28

M I LITARY M A R K ET
N o . :
S U BJ ECT
DOLBY rnn:r ENC Y
C HA RAC T E R. I :::, TIC
-iORSENING
1
RS-B l lW
j_
Date :
Symp tom
When r e c o rded and played in me tal tape pos ition , the
frequency charac t e ristic wors ens .
( Lowered 3 - 5 dB in med ium frequency range )
. . . . . only with Dolby IN .
Cau s e
Bias leak voltage i s applied t o the Dolby circuit caus ing
faulty operation of the circuit .
Bias leak i s s ignificant in metal position b e cau s e of
x
high bias o s c illat ion voltage .
,,- The above-men t ioned symptom appears wLen bias leak of
LINE OUT is about 1 . 7 mV .
Remedy
Improvement of lead wire arrangement
*
Bias leak incre a s e s as the parallel cable f r om INPUT
VR come s clo s e to the rec/playback head conn e c t o r of
main P . C . B .
Panasonic Service
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