Philips DVDR890, Руководство по обслуживанию, Страница: 42 / 116

Alignments EN 145 DVDR880-890 /0X1 8.
8. Alignments
8.1 Alignment Instructions Analogue Board
Figure 8-1
TP ADJ. MODE INPUT
Frequency-
Counter Disc
R3054
Pin 2 of
Con.1911
(FMRV)
3,800MHz
±10kHz
DISC MEAS.EQ.
MEAS.EQ.
MEAS.EQ.
MEAS.EQ.
SPEC.
TUNER
component
adjustment Specification
Measuring
equipment
measuring
equipment
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:
Front End (FV)
Service tasks after replacement of IC 7710, coil L5710 and L5711:
1 AFC Adjustment:
Purpose:
Storage in NVRAM via command mode interface of DSW:
Correct adjustment of demodulator AFC - circuit
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
Symptom, if incorrectly set:
Bad or disturbed TV channel reception.
PAL - AFC adjustment [5711]:
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 INPUT
DC Voltmeter
Frequ. Generator
TUNER
38,9MHz 500mV
pp
at Tuner 1705, Pin 11
(F710, IF-out)
2,5V ±0,1V
DISC
DISC
DISC
SPEC.
L5711
IC 7710
Pin 17
(F708)
TP ADJ. MODE INPUT
5mV(74dBµV)
on aerial input
PAL white picture,
audio IF on,
no modulation
SPEC.
R3707
Oscilloscope
Video Pattern
Generator
500mV
pp
+/-0.5dB
(use a 10:1 probe )
Set tuned to
channel 25
503.25 MHz
Tuner
1705
Pin 11
(F710,
IF-out)
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).
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.
TP ADJ. MODE INPUT
L5710
Oscilloscope,
Sinus Generator,
Counter
adjust minimum
amplitude
TUNER
OFW
1701
Pin 1
(F709)
40.4 MHz, 200mV
rms
at Tuner 1705, Pin 11
(F710, IF-out)
SPEC.