Alignments; Figure - Philips DVDR880/001 Service Manual

8. Alignments

8.1 Alignment Instructions Analogue Board
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:
measuring
equipment
component
TP ADJ.
Pin 2 of
R3054
Con.1911
(FMRV)
DISC
Disc
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.
IC 7710
Pin 17
L5711
(F708)
DISC
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
MODE INPUT
TUNER
MEAS.EQ. SPEC.
Frequency- 3,800MHz
Counter ±10kHz
Measuring
equipment
Specification
MODE INPUT
38,9MHz 500mV
TUNER
at Tuner 1705, Pin 11
(F710, IF-out)
MEAS.EQ. SPEC.
DC Voltmeter
2,5V ±0,1V
Frequ. Generator
Alignments
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.
Tuner
1705
R3707
Pin 11
(F710,
IF-out)
DISC
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.
OFW
1701
L5710
Pin 1
(F709)
DISC
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.
pp

Figure 8-1

DVDR880-890 /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
(F710, IF-out)
SPEC.
MEAS.EQ.
Oscilloscope,
adjust minimum
Sinus Generator,
amplitude
Counter
8. EN 145
rms