Grundig GV 6400 HiFi Service Anleitung Seite 34

Adjustment Procedures
3.2 Family Board – Frontend (FV)
Test equipment: Oscilloscope with 10:1 Test Probe, Voltmeter, Colour Generator
Service work after replacing the
... Tuner: Adjustments no. 2
... IC7720 (TDA9800T): Remove R3743
Adjustment
1. Demodulator Circuit Voltmeter: ................................. IC7720-(15) or IC7721-(20)
EE-mode
PAL, F5725 Colour generator 38.9MHz / 500mV
(AFC)
SECAM-L, IC7723-(7) and T7726 – connect the collector to GND (activates
R3748 SECAM – Band I)
(Band I)
Colour generator 33.9MHz / 500mV
2. Delayed AGC Feed in a PAL white test pattern with sound carrier (without
Voltage, sound modulation, UHF-range, Ch27, 74dBµV aerial signal)
R3742 into the warmed-up VCR.
(AGC)
Oscilloscope: .............................................. Tuner 1701-(17)
EE-mode
3.3 Family Board – Video/Chroma (VS)
Test equipment: Oscilloscope with 10:1 Test Probe, Frequency Counter, Colour Generator
Adjustment
1. Sync Frequency AV recording (do not feed in a signal).
Frequency counter: ...................... wire bridge 9013 (FMRV)
R3057
(Sync. Frequ.)
2. SECAM-L Chroma Connect IC7051-(2) to +5V (pin 13).
Oscilloscope: ................................ wire bridge 9013 (FMRV)
Recording Current,
R3042 Feed in a SECAM-L red raster test pattern with 75% saturation
(SECAM-Curr.)
(ratio burst: chroma = 1 : 2.2) into the AV socket and record it.
3.4 Family Board – Erase Oscillator / Standard Sound (AL)
Test equipment / jigs: Frequency Counter, AF Millivoltmeter, AF Generator, Colour Generator, branded Video Cassette.
Service work after replacing the RP-Head: Adjustment no. 1.1; Family Board II – Audio (AF): Adjustment no. 1
Adjustment
1. Erase Frequency, Frequency counter: .................... wire bridge 9611 (BIAS-R)
F5603 Record
(BIAS R)
1.1 Bias, R3618 AF millivoltmeter: ........................................................ R3600
(BIAS)
Record
1.2 Frequency – Feed in a CCVS signal via EURO-AV socket, contact 20.
Response Test – Feed an audio signal of 200mV
the EURO-AV socket, contact 2 or 6.
– Make a recording of 400Hz and 8kHz each of 1 min at least.
Afterwards play back these recordings (switch to standard sound).
– Connect an AF millivoltmeter (oscilloscope) to EURO-AV
socket, contact 1 or 3.
4. Family Board II (PAF)
4.1 Family Board II – Stereodecoder (SD)
Test equipment / jigs: AF Millivoltmeter, AF Generator, Colour Generator
Service work after replacing the IC7780: Adjustment no. 1, 2
Adjustment
1. Stereo Level Call up the Service Test Programme (see page 1-16).
Call up Level 60 (see page 1-16).
2. Crosstalk Call up the Service Test Programme (see page 1-16).
Call up Level 61 (see page 1-16).
4.2 Family Board II – Audio (AF)
Test equipment / jigs: AF Millivoltmeter, AF Generator
Service work after replacing the RP-Head or the IC7100: Adjustment no. 1
Adjustment
1. Playback Level Call up the Service Test Programme (see page 1-16).
Call up Level 62 (see page 1-16).
3 - 4
. The new TDA9800T automatically sets a "Default" value.
(Phase Offset)
Preparation
........... Tuner 1701-(17)
PP
: .......... Tuner 1701-(17)
PP
Preparation
Preparation
from the AF generator to
rms
Preparation
Preparation
Adjustment Procedure
Set the voltage with F5725
(AFC)
Set the voltage with R3748
(Band I)
Disconnect IC7723-(7) and T7726 – collector from GND.
Set the amplitude with R3742
(AGC)
Adjustment Procedure
Set frequency with R3057
(Sync. Frequ.)
Set Chroma signal with R3042
(SECAM-Curr.)
of the FM-signal).
Disconnect IC7051-(2) from +5V.
Adjustment Procedure
With F5603 set the reading on the frequency counter
(BIAS R)
±
to 70kHz 10kHz.
Set the voltage drop across R3600 with R3618
Check the frequency response.
The voltage ratio of 400Hz to 8kHz must not be higher than
1:0.7 or 0.7:1 (±3dB). If the voltage ratio exceeds these limits,
the bias must be altered:
To increase the playback voltage at 8kHz: Reduce "BIAS".
To reduce the playback voltage at 8kHz: Increase "BIAS".
Adjustment Procedure
Observe the instrucitons for Level 60 (see page 1-17).
Terminate the Service Test Programme (see page 1-16).
Observe the instrucitons for Level 61 (see page 1-17).
Terminate the Service Test Programme (see page 1-16).
Adjustment Procedure
Observe the instrucitons for Level 62 (see page 1-18).
Terminate the Service Test Programme (see page 1-16).
GV 6400 ..., GV 6401 NIC
±
to 2.5V 0.2V.
±
to 2.5V 0.2V.
to 550mV +0/-50mV.
PP
±
to 3.8MHz 10kHz.
to 42mV (-17dB
PP
to 15mV .
(BIAS)
rms
GRUNDIG Service