Table of Contents
Advertisement
| ¢-3RX
5-6-2 DECODER ADJUSTMENT
|
1, Preset all adjustors approximately to the center position.
8. Repeat above steps 5 to 7 until the best results are obtained.
2. Make the Fig. 5-17. connections, then feed 100 Hz, —8 dB (308
9. Check that when the input signal is 100 Hz/—8 dB (308 mV),
mV) to the F/I (INPUT) terminal.
then 10 kHz/—8 dB, the output signal from H/J (OUTPUT)
3. Adjust R77/R87 to obtain a clear 200 Hz sine-wave on the
terminal deviates by —1 dB +0.5 dB, then +5.5 dB +0.5 dB from
oscilloscope. See Fig's 5-12 and 5-13.
—8 dB (reference), respectively ... $0 that output, as a voltage
4. Change the connections to Fig. 5-18, then feed a 1 kHz/—8 dB
value, should be 652 mV to 731 mV for 100 Hz, and 1.38 V
(308 mV) input signal to the INPUT terminal. Adjust R73/R83
to 1.55 V for 10 kHz.
so that AC voltmeter reads —8 dB (308 mV).
10. Check that when 1 kHz/—38 dB (9.75 mV) is applied, the out-
|
5. With the conditions in step 4, adjust R71/R81 for minimum
put is —68 dB +7 dB (275 pV to 346 pV).
|
distortion (0.1% or less).
11. Check that when the input signal is 1 kHz, +2 dB (0.975 V), the
|
6. Like Fig. 5-19', connect a DC voltmeter between TP5 and TP13
output is +12 dB +1 dB (2.75 V to 3.46 V) and the distortion
for L-ch (or TP7 and TP15 for R-ch), then note the reading on
factor is 0.3% or less.
the DC voltmeter with an input signal of 1 kHz/—8 dB (308 mV).
7. Cut off the input signal, connect TP6/TP8 to the E (0 V) termi-
nal, then make the same measurement as in step 6 to adjust
R72/R82 for the same level.
Low distortion
:
AF OSCILLATOR
AC VOLTMETER
OSCILLOSCOPE
Distortion: 0.02% or less
Output: 3V or more
NOTE: Lech (Rech)
Fig.5-17
Connections for DECODER adjustment (1)
Low distortion
:
AF OSCILLATOR
.
AC VOLTMETER
OSCILLOSCOPE
ATTENUATOR
DBX
PCB
Distortion: 0.02% or less
Output: 3V or more
DISTORTION
ad
METER
NOTE: Lch (Rch)
Fig. 5-18
Connections for DECODER adjustment (2)
Low distortion
AF OSCILLATOR
DC VOLTMETER
Distortion: 0.02% or less
Output: 3V or more
NOTE: Lch (Reh)
Fig. 5-19
Connections for DECODER adjustment (3)
17
Advertisement
Table of Contents
