Sony STR-AV220 - Page 4

STR-AV220/AV320 :
SECTION 2
ELECTRICAL ADJUSTMENTS
FM SECTION
e FM Discriminator (NULL) Adjustment
Setting :
FM RF stereo signal
generator
Carrier frequency : 98MHz
Output level : 60dBy
Modulation : 1kHz
FM ANTENNA 3000
75kHz dev. terminal
(100%) VOM
TP1 (DC range)
NULL terminal
fen
Procedure :
1. Tune the set to 983MHz.
2. Adjust T21 for 0V reading on the VOM.
Note : FM Tuning Level adjustment should be made after
FM discriminator adjustment.
e FM Stereo Operation Level Adjustment
Setting:
FM RF stereo signal
generator
Carrier frequency : 98MHz
Output level: 25dBu
Modulation : IkHz
75kHz dev.
(100%)
Procedure:
1. Tune the set to 98MHz.
2. Adjust RV24 so that the STEREO LED goes on.
FM ANTENNA 3000
terminal
Note on Ceramic Filter (CF1, 2) Replacement.
This set employs two ceramic filters (CF1, 2) which should
have the same color marking to identify their center fre-
quency. Therefore FM IF offset adjustment by (* A, * B)
connection is necessary to match the center frequency of the
ceramic filters used with FM intermediate frequency.
color marking
la
e FM Stereo Separation Adjustment
Setting:
FM RF stereo
signal
generator
FM ANTENNA 3000
terminal
REC OUT
Carrier frequency : 98MHz
Output level: 6OdBu
Modulation :
Audio (1kHz): 33.75kHz dev. (45%)
Pilot (19kHz): 7.5kHz dev. (10%)
Sub-channel (38kHz) : 33.75kHz dev. (45%)
Procedure:
Tune the set to 98MHz.,
FM stereo
signal generator
output channel
VTVM
connection
VTVM
reading (dB)
L-CH A)
®
Adjust RV21 for
minimum reading.
©
©
Adjust RV21 for
minimum reading.
L-CH
L-CH Stereo separation: @—-®
R-CH Stereo separation: ©O-®O
The separations of both channels should be equal.
©: short
X : open
Ceramic filter Connection | FM intermediate
frequency
Color
|Center
frequency}
*
A
(MHz)
10.750
10.700
10.650