Electrical Adjustments - Sony SRS-RF90RK Service Manual

TMR-RF90
Setting :
AF signal
generator
Frequency counter
Transmission Frequency Check and Adjustment
1. Set the NOISE FILTER switch to off.
2. Input a signal of 1 kHz 40 mVrms to only the L-CH (J402).
3. Connect a telescopic antenna to the frequency counter input and
extend the antenna to a length of approximately 8 cm.
4. Place TX board close to the frequency counter, then measure the
frequencies of CH1, CH2 and CH3 and make sure the values are
as follows:
CH1 : 913.5 MHz ± 200 kHz
CH2 : 914.0 MHz ± 200 kHz
CH3 : 914.5 MHz ± 200 kHz
When the frequency is not satisfied the specified value, set the
CHANNEL switch (S402) to CH2, then adjust the value of the
frequency counter to 914.0 MHz by trimmer capacitor in the VCO
unit.
Standard value :913.9MHz to 914.1MHz
When completed with replacement, recheck the
frequencies of CH1, CH2 and CH3.
SECTION 3

ELECTRICAL ADJUSTMENTS

set
TMR-RF90
L-CH (J402)
Telescopic
antenna
set
8 cm
TMR-RF90
SRS-RF90R/RF90RK/TMR-RF90
Modulation Check and Adjustment
1. Set the channel to CH2.
2. An electric wave is output for 5or 10 minutes when off to on a
power supply (Power indicator will on).
3. Measure the center terminal of RV403 using an digital volt-meter
(AC range) and make sure the value is 2 to 2.5mVrms.
If the measured value is other than the specified value, adjust to
2 to 2.5mVrms by turning the RV403 on the TX board.
Connection points and Adjustment Location :
(Component side)
TX BOARD
CH3 ← CH2 ← CH1
(L-CH) (R-CH)
S402
RV403
VCO UNIT
RV403: Modulation adjustment
TX BOARD
(Conductor side)
digtal voltmeter
(AC range)
J402
Hole
Trimmer : Transmission
frequency adjustment
IC402
9