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8. Alignments
8.1
Alignment Instructions Analogue Board
Alignments Analog PCB Eur
Test equipment:
1. Dual-trace oscilloscope
Voltage range
Frequency
Probe
2. DVM (Digital voltmeter)
3. Frequency counter
4. Sinus generator
Sinus
5. Test pattern generator
How to read the adjustment procedures:
Connecting point
(Test Point) of
measuring
equipment
Adjustment
component
TP
ADJ.
Pin 2 of
R3054
Con.1911
(FMRV)
DISC
Disc
Disc needed for
adjustment
Front End (FV)
Service tasks after replacement of IC 7703, coil L5702 and L5703:
1 AFC Adjustment:
Purpose:
Correct adjustment of demodulator AFC - circuit
Symptom, if incorrectly set:
Bad or disturbed TV channel reception.
PAL - AFC adjustment [5703]:
TP
ADJ.
IC 7703
Pin 17
L5703
(I976)
DISC
Frequ. Generator
Storage in NVRAM via command mode interface of DSW:
After adjustment, the AFC reference value has to be stored in the NVRAM.
This reference value is 256 * measured voltage/Ucc. Ucc is 5.0V.
Store the reference value via command 732 , followed by the ref. value.
Example: DD:> 732 128
: 0.001 ~ 50 V/div
: DC ~ 50 MHz
: 10:1, 1:1
: 0 ~ 50 MHz
DVDR mode:
Example using:
DVDR TUNER
Test signal
required for the
adjustment and
feed in point
MODE
INPUT
TUNER
MEAS.EQ.
SPEC.
Frequency-
3,800MHz
Counter
±10kHz
Measuring
Adjustment
equipment
Specification
MODE
INPUT
38,9MHz 500mV
TUNER
at Tuner 1705, Pin 11
(F700, IF-out)
MEAS.EQ.
SPEC.
DC Voltmeter
2,5V ±0,1V
Alignments
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.
TP
ADJ.
Tuner
1705
R3707
Pin 11
(F700,
IF-out)
DISC
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).
TP
ADJ.
OFW
1700
L5702
Pin 1
(F704)
DISC
If the adjustment is correct the signal at pin 1 of OFW [1700] must be
smaller than the input signal amplitude by at least 6 dB.
pp
Figure 8-1
DVDR980-985 /0X1
MODE
INPUT
5mV(74dBµV)
on aerial input
Set tuned to
PAL white picture,
channel 25
audio IF on,
503.25 MHz
no modulation
SPEC.
MEAS.EQ.
Oscilloscope
500mV
+/-0.5dB
pp
Video Pattern
(use a 10:1 probe )
Generator
MODE
INPUT
40.4 MHz, 200mV
TUNER
at Tuner 1705, Pin 11
(F700, IF-out)
MEAS.EQ.
SPEC.
Oscilloscope,
adjust minimum
Sinus Generator,
amplitude
Counter
CL 16532145_061.eps
8.
EN 157
rms
041201
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