Page 2
Ð 3 ÐÐ 4 Ð
SECTION 2
ELECTRICAL ADJUSTMENTS
Note :
1. The transmitter section adjustments should be completed before
performing the headphones section adjustment.
2. On adjusting the transmitter section, use the headphones as a
jig.
Transmitter Headphones
TMR-RF450RMDR-RF430
MDR-RF450
Setting :
Send Frequency Check and Adjustment
1. Set the noise filter SW to OFF.
2. Input a signal of 1kHz 40mVrms to only the L-ch (J403).
3. Connect a telescopic antenna to the frequency counter input and
extend the antenna to a length of approximately 13cm.
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 : 433.3 Ð 433.5MHz
CH2 : 433.8 Ð 434.0MHz
CH3 : 434.3 Ð 434.5MHz
If the measured values are other than the values specified above,
adjust the frequencies by turning RV402 and RV403 on the TX
board. When completed with adjustment, recheck the frequencies
of CH1, CH2 and CH3.
Connection points and Adjustment Location :
TX board (See page 4)
Sub-Carrier (L-R) Modulation Check and Adjustment
1. Set the noise filter SW to OFF.
2. Set the channel to CH2.
3. Input a signal of 1kHz 316mVrms to only the L-ch (J403).
4. Measure the pin 1 voltage of the TX board IC403 using an
digital voltmeter (AC range) and make sure the value is 220 Ð
250mVrms. If the measured value is other than the specified
value, adjust to 235mVrms by turning the RV401 on the TX
board.
Connection points and Adjustment Location :
TX board (See page 4)
3.4-3.8Vp-p
AF signal
generator
telescopic
antenna
13cm L-CH (J403)
TMR-RF450Rset TMR-RF450Rset
frequency counter
MDR-RF430
MDR-RF450 headphones
battery terminal (DC 3V)
Sub-Carrier Frequency Check and Adjustment
1. Set the noise filter SW to OFF.
2. Set the channel to CH2.
3. Input a signal of 1kHz 316mVrms to only the L-ch (J403).
4. Connect a frequency counter and an oscilloscope between the
Q409 emitter and GND.
5. Set the TX board L-ch (J403) input to OFF (not doing so will
cause modulation in the sub-carrier, preventing correct measure-
ment)
6. Check to make sure the frequency counter reading is 48 Ð52kHz.
If the measured value is other than the specified value, adjust
the frequency to 50kHz by turning the RV405 on the TX board.
In addition, check to make sure the oscilloscope waveform is as
follows :
(Perform the check and adjustment within one minute since the
transmitter AUTO OFF function will be activated approximately
one minute after setting the transmitter L-ch input to OFF. If the
AUTO OFF function activates, set the L-ch input to ON, set TX
board to AUTO ON, set the L-ch input again to OFF, then make
the check adjustment.)
Connection points and Adjustment Location :
TX board (See page 4)
Main Carrier Modulation Check and Adjustment
1. Set the channel to CH2.
2. Set the noise filter SW to OFF.
3. Input a signal of 1kHz 316mVrms to only the transmitter Lch
(J403).
4. Set headphones VOL (RV301) to MIN.
5. Connect an digital voltmeter (AC range) and oscilloscope be-
tween IC301 pin @Á and GND on RX board (headphones).
6. Receive signals by turning headphones TUNING VOL (RV302).
7. First check to make sure that a demodulated waveform of 1kHz
is outputted to the oscilloscope, then check to make sure the
digital voltmeter (AC range) reading is AC 12 Ð15mVrms. If the
reading is not within the specified range, turn RV404 on the TX
board so that the reading is 13.5mVrms.
HEADPHONES
[ RX BOARD ] (Conductor side)
Connection points and Adjustment Location :
TX board (See page 4)
oscilloscope
digital voltmeter
(AC range)
Connection points :
Adjustment Location :
S402
Channel Select Switch
RV403 (R-CH) RV402 (L-CH)S401
Noise Filter ON/OFF Switch J402
(R-CH)
RV404 : Main Carrier
Modulation Adjustment
RV401 : Sub-Carrier (L- R) Modulation Adjustment
RV405 : Sub-Carrier Frequency AdjustmentSend Frequency
Adjustment
J403
(L-CH)
[TX BOARD] (Component side)
[ TX BOARD ] (Conductor side)
digital voltmeter
(AC range)
frequency counte r
oscilloscope
