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8. Alignments
8.1
Alignment Instructions Analog 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:
DVDR mode:
Example using:
DVDR TUNER
Connecting point
(Test Point) of
measuring
equipment
Adjustment
component
TP
ADJ.
MODE
Pin 2 of
R3054
TUNER
Con.1911
(FMRV)
DISC
MEAS.EQ.
Frequency-
Disc
Counter
Measuring
Disc needed for
equipment
adjustment
Front End (FV)
Service tasks after replacement of IC 7710, coil L5710 and L5711:
1 AFC Adjustment:
Purpose:
Correct adjustment of demodulator AFC - circuit
Symptom, if incorrectly set:
Bad or disturbed TV channel reception.
PAL - AFC adjustment [5711]:
TP
ADJ.
MODE
IC 7710
Pin 17
L5711
TUNER
(F708)
DISC
MEAS.EQ.
DC Voltmeter
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 1119 , followed by the ref. value.
Example: DD:> 1119 128
Test signal
required for the
adjustment and
feed-in point
INPUT
SPEC.
3,800MHz
±10kHz
Adjustment
Specification
INPUT
38,9MHz 500mV
pp
at Tuner 1705, Pin 11
(F710, IF-out)
SPEC.
2,5V ±0,1V
Figure 8-1
Alignments
DVDR730/0x
2 HF - AGC adjustment [3724]:
Service tasks after replacement of IC 7710:
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.
MODE
Tuner
1705
Set tuned to
R3707
Pin 11
channel 25
(F710,
503.25 MHz
IF-out)
DISC
MEAS.EQ.
Oscilloscope
Video Pattern
Generator
3 Attenuating the 40.4 MHz [5710]:
(SECAM only)
Service tasks after replacement of coil 5710:
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.
MODE
OFW
TUNER
1701
L5710
Pin 1
(F709)
DISC
MEAS.EQ.
Oscilloscope,
Sinus Generator,
Counter
If the adjustment is correct the signal at pin 1 of OFW [1701] must be
smaller than the input signal amplitude by at least 6 dB.
8.
EN 117
INPUT
5mV(74dBµV)
on aerial input
PAL white picture,
audio IF on,
no modulation
SPEC.
500mV
+/-0.5dB
pp
(use a 10:1 probe )
INPUT
40.4 MHz, 200mV
rms
at Tuner 1705, Pin 11
(F710, IF-out)
SPEC.
adjust minimum
amplitude
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