Electrical Adjustments; Test Mode; Md Section; Tuner Section - Sony MDX-C7970/C7970R Service Manual

TEST MODE

This set have the test mode function. In the test mode, FM Auto
Scan/Stop Level and AM (MW) Auto Scan/Stop Level adjustments
can be performed easier than it in ordinary procedure.
<Set the Test Mode>
1. Turn ON the regulated power supply. ( The clock is displayed)
[OFF]
Note: Press the button, if the clock is not displayed.
[4]
2. Push the preset button.
[5]
3. Push the preset button.
[1]
4. Press the preset button for more than two seconds.
5. Then the display indicates all lights, the test mode is set.
<Release the Test mode>
[OFF]
1. Push the button.
See the adjustment location from on page 22 for the ad-
justment.

MD SECTION

MD section adjustments are done automatically in this set.
SECTION 3

ELECTRICAL ADJUSTMENTS

Note: Adjust the tuner section in the sequence shown below.
1. FM Auto Scan/Stop Level Adjustment
2. FM Stereo Separation Adjustment (MDX-C7970)
3. FM Stereo Separation Adjustment (Wide) (MDX-C7970R)
4. FM Stereo Separation Adjustment (Narrow) (MDX-C7970R)
5. FM RDS S-Meter Adjustment (MDX-C7970R)
6. AM (MW) Auto Scan/Stop Level Adjustment
FM Auto Scan/Stop Level Adjustment
Setting:
Procedure:
1. Set to the test mode.
2. Push the
3. Adjust the volume RV2 on TU1 by turning clockwise untill
*1: MDX-C7970R indicates "98.00".
Adjustment Location: See page 22.
– 18 –

TUNER SECTION

Cautions during repair
When the tuner unit is defective, replace it by a new one be-
cause its internal block is difficult to repair.
[SOURCE]
button
FREQUENCY SELECT switch : FM 200 k (E model)
FM RF signal
generator
Carrier frequency : 97.9 MHz (MDX-C7970)
98.0 MHz (MDX-C7970R)
: 22 dB (12.6 µ V)
Output level
Mode : mono
Modulation : 1 kHz, 22.5 kHz deviation (30%)
[SOURCE]
button and set to FM.
Display
"0" is shown next to "FM" on the display window, If "0" is
already shown or the volume RV2 has been turned too far,
turn it back counterclockwise untill "0" is disappeared once,
then try this adjustment.
Display
0 dB=1 µV
: FM
antenna jack (CN1)
0.01 µ F
set
SHUF
*1
SHUF
*1