Yamaha DRX-1, Service Manual, Page: 69 / 192

DRX-1 DRX-1
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ALIGNMENTS
1. Alignment Instructions Analogue Board
Alignments Analog PCB Eur
ADJUSTMENT INSTRUCTIONS ANALOGUE BOARD
Test equipment:
1. Dual-trace oscilloscope
Voltage range : 0.001 ~ 50 V/div
Frequency : DC ~ 50 MHz
Probe : 10:1, 1:1
2. DVM (Digital voltmeter)
3. Frequency counter
4. Sinus generator
Sinus : 0 ~ 50 MHz
5. Test pattern generator
How to read the adjustment procedures:
TP ADJ. MODE INPUT
Frequency-
Counter Disc
R3054
Pin 2 of
Con.1911
(FMRV)
3,800MHz
±
10kHz
DISC MEAS.EQ. SPEC.
TUNER
DVDR mode:
Example using:
DVDR TUNER
Adjustment
component
Test signal
required for the
adjustment and
feed-in point
Disc needed for
adjustment
Adjustment
Specification
Measuring
equipment
Connecting point
(Test Point) of
measuring
equipment
Front End (FV)
Service tasks after replacement of IC 7703, coil L5702 and
L5703:
1.1 AFC Adjustment:
Purpose: Correct adjustment of demodulator AFC - circuit
Symptom, if incorrectly set:
Bad or disturbed TV channel reception.
PAL - AFC adjustment [5703]:
MEAS.EQ.
TP ADJ. MODE INPUT
DC Voltmeter
Frequ. Generator
TUNER
38,9MHz 500mV
pp
at Tuner 1705, Pin 11
(F700, IF-out)
2,5V
±
0,2V
DISC SPEC.
L5703
IC 7703
Pin 17
(I976)
1.2 HF - AGC adjustment [3707]:
Service tasks after replacement of IC 7703:
Purpose: Set amplifier control.
Symptom, if incorrectly set:
Picture jitter if input level is too low and picture distortion
if input level is too high.
MEAS.EQ.
DISC
TP ADJ. MODE INPUT
4,5mV(74dB
µ
V)
on aerial input
PAL white picture,
audio IF on,
no modulation
SPEC.
R3707
Oscilloscope
Video Pattern
Generator
550mV
pp
+/-50mV
(use a 10:1 probe )
Set tuned to
channel 27
Tuner
1705
Pin 11
(F700,
IF-out)
1.3 Attenuating the 40.4 MHz [5702]: (SECAM only)
Service tasks after replacement of coil 5702:
Purpose: To attenuate the band I carrier rests.
Symptom, if incorrectly set:
Bad picture quality when the filter attenuates the picture
carrier (38.9MHz).
MEAS.EQ.
DISC
TP ADJ. MODE INPUT
L5702
Oscilloscope,
Sinus Generator,
Counter
adjust minimum
amplitude
TUNER
OFW
1700
Pin 1
(F704)
40.4 MHz, 300mV
rms
at Tuner 1705, Pin 11
(F700, IF-out)
SPEC.
If the adjustment is correct the signal at pin 1 of OFW
[1700] must be smaller than the input signal amplitude by
at least 5 dB.
2. Reprogramming Procedure of NVM on the
Analogue PCB
The NVM, item 7815, on the Analogue board contains the
following factory settings:
1. Bargraph 0dB correction factor
2. Clock correction factor
3. AFC reference value
4. Slash version
The settings 1,2 and 3 are stored in the NVM during the
production of the analogue board.
The slash version is stored at the end of the production
line of the set.
In case of failure, the NVM must be replaced by an empty
device. By way of commands via the Diagnostic Software
or via ComPair, the factory settings must be restored in
the NVM.