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GV470S...
2.2 Family Board – Teletext "DOS" (VT)
Test Equipment: Two-channel Oscilloscope, 1:1 Test Probe (TK).
Service work after replacing the Family Board: –
Adjustment
1. H/2 Sync
Oscilloscope:
Adjustment, F1040
Channel 1: .................................................... IC7190-(10)
(necessary after
Channel 2: ...................................................... IC7190-(7)
replacing F1040 or
Trigger: ....................... Channel 2, negative going edge.
C2139)
Feed in a HF signal (PAL) / Record or EE mode without
Texttable.
2.3 Family Board – Frontend (FE)
Test Equipment: Oscilloscope (>50MHz), 10:1 Test Probe, Voltmeter, Colour Generator with Stereo Coder, Distortion Factor Meter, Stabilized Power Supply.
Service work after replacing the Tuner: Adjustment no. 2
Adjustment
1. Vision Demodula-
Initializing the RAM and EEPROM (2.1 Sequence Control/
tor Circuit,
Deck Electronic – Adjustment no. 1)
F1184 (AFC-ADJ)
Power Supply, 2.3V (AFC disabled): ................. MP
Feed in a TV standard test pattern (Ch12, Ch21, Ch68, Ch8
or Ch60; see "Initializing the RAM and EEPROM").
Voltmeter: ........................................................... MP
Mode "Fine Tuning)
2. Delayed AGC
Solder a 4.7pF capacitor to MP
Voltage,
pe with 10:1 test probe to the free connection of the capacitor.
R3881 (AGC-ADJ)
Feed in a standard test pattern without audio modulation (UHF-
range, Ch26, 67dBµV aerial signal) into a warmed-up set.
EE mode.
3. Quasi-Split-Sound
Feed in a standard test pattern (UHF-range, Ch26, aerial
(QSS),
signal >60dBµV ) into a warmed-up set.
F1160 (REF-ADJ)
Distortion factor meter (or oscilloscope)
with 10:1 test probe: ........................................... MP
EE mode.
4. FM-Demodulator
Feed in a 2-channel sound standard test pattern with the
colour generator, 1kHz sine, ±27kHz deviation.
(FM-Sound 1),
F1170 (FM1-ADJ)
Distortion factor meter (or oscilloscope): ........... MP
EE mode.
5. FM-Demodulator
Feed in a 2-channel sound standard test pattern with the
colour generator, 1kHz sine, ±27kHz deviation.
(FM-Sound 2),
F1188 (FM2-ADJ)
Distortion factor meter (or oscilloscope): ........... MP
EE mode.
6. Cross Talk
Feed in a standard test pattern with sound modulation
"stereo".
Oscilloscope: ...................................................... MP
RF recording.
Call up the service function:
– Press the
(" CODE – – – – " is indicated in the display).
– Enter the code number
button (" SERV " is indicated in the display).
7. ATS-Adjustment
Feed in a standard test pattern (UHF-range, Ch26, 50dBµV
aerial signal).
RF recording.
Call up the service function:
– Press the
(" CODE – – – – " is indicated in the display).
– Enter the code number
button (" SERV " is indicated in the display).
GRUNDIG Servicetechnik
Preparation
Preparation
. Connect the oscillosco-
87
Z
button on the remote control handset
4 9 3 4
and press the
Z
button on the remote control handset
4 9 3 4
and press the
Abgleichvorschriften / Adjustment Procedures
Adjustment Procedure
Set the time interval with F1040 between the middle of the
H/2-SYNC (IC7190-(7)) pulse and the negative going edge
of the SYNC (IC7190-(10)) to
IC7190-(10)
IC7190-(7)
Adjustment Procedure
Set the voltage with F1184 (AFC-ADJ) to 2.5V
84
86
Set the amplitude with R3881 (AGC-ADJ) to 40mV
Unsolder the 4.7pF capacitor.
Set the distortion with F1160 (REF-ADJ) to Minimum
(or adjust for best sine wave possible on the oscilloscope).
82
Set the distortion with F1170 (FM1-ADJ) to Minimum
(or adjust for best sine wave possible on the oscilloscope).
82
Set the distortion with F1188 (FM2-ADJ) to Minimum
(or adjust for best sine wave possible on the oscilloscope).
83
Set the cross talk to Minimum:
Coarse: with remote control button
82
Fine: with remote control button
To cancel the service function: Press the "Standby" button
or disconnect the recorder from the mains.
O
. The display shows " ATS† 00 00 A7 ".
7
Press the button
To cancel the service function: Press the "Standby" button
or disconnect the recorder from the mains.
O
∆
µ
±
µ
t = 32
s
10
s.
∆t
64µs
±
0.1V.
.
PP
= " L † ",
= " L -- "
1
2
3
= " S † ",
4
= " S -- "
3 - 7
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