Adjustment ProceduresGV 27 EURO, GV 7� EURO
1.4 Chassis Board � Frontend (FV)
Test equipment: Oscilloscope with 10:1 Test Probe, Voltmeter, AF Millivoltmeter, Colour Generator
Service work after replacing the
� Tuner, IC7720, IC7721:Adjustments no. 2
� IC7720 (TDA9800T):Remove R3748 (PLL). The new TDA9800T automatically sets a "Default" value.
� IC7780:Adjustments no. 4, 5
AdjustmentPreparationAdjustment Procedure
1. Demodulator CircuitVoltmeter:.................................IC7720-(15) or IC7721-(20)
EE-mode.
PAL, F5725 (AFC)Colour generator 38.9MHz - 500mVPP: ......Tuner 1701-(17)Set the voltage with F5725 (AFC) to 2.5V ?0.2V.
SECAM-L,Colour generator 33.9MHz / 500mV: ......Tuner 1701-(17)Set the voltage with R3748(Band I) to 2.5V ?0.2V.
PP
R3748(BandI)Press button "SYSTEM" repeatedly until "SEC" is displayed.
2. Delayed AGCFeed in a PAL white test pattern with sound carrier (without soundSet the amplitude with R3742 (AGC) to 550mVPP +0/-50mV.
Voltage,modulation, Ch27, 74dBmV aerial signal) into the warmed-up VCR.
R3742(AGC)Oscilloscope:..............................................Tuner 1701-(17)
EE-mode.
3. Residual CarrierColour generator 40.4MHz - 300mV: ......Tuner 1701-(17)Set the amplitude with F5721 (40.4MHz) to minimum (5dB
PP
Band I,Oscilloscope:........................................................F1720-(1)lower at least than the input signal).
F5721 (40.4MHz)EE-mode.
4. Stereo LevelCall up the Service Test Programme (see page 2-4).Observe the instructions for Level 60 (see page 2-6).
Call up Level 60 (see page 2-4).Terminate the Service Test Programme (see page 2-4).
5. Cross TalkCall up the Service Test Programme (see page 2-4).Observe the instructions for Level 61 (see page 2-6).
Call up Level 61 (see page 2-4).Terminate the Service Test Programme (see page 2-4).
1.5 Chassis Board � Video/Chroma (VS, VS-S)
Test equipment: Oscilloscope with 10:1 Test Probe, Colour Generator
Service work after replacing the IC7007 or 7110:Adjustment no. 1
AdjustmentPreparationAdjustment Procedure
1. Chroma RecordingRemove the drive mechanism (see page 1-9)The FMF signal must have an amplitude of 420mVpp. If the
CurrentCall up the Service Test Programme � Level 10 (see page 2-4)value deviates by more than ?40mV there is a technical
pp
Feed in a PAL red raster test pattern with 75% saturation (ratiodefect (e.g. IC7007).
burst: chroma = 1 : 2.2) into the AV1 socket and record it.
Oscilloscope:................................ R3031 (T7006 � Emitter)
Connect R3031 (T7006 � Emitter)L5001 (5VASW). to
PAL,Oscilloscope:................................................Set Chroma signal with R3007 � wiperR3007 (PAL-Curr.) to160 mV ?20mV
PPPP
R3007(PAL-Curr.)Feed in a PAL red raster test pattern with 75% saturation (ratio(for 2-Head-VCR) or 130mVPP ?20mVPP (for 4-Head-VCR).
burst: chroma = 1 : 2.2) into the AV1 socket and record it.
SECAM-L,Oscilloscope:................................................Set Chroma signal with R3159 � wiperR3159(SECAM-Curr.) to 210mVPP ?30mVPP.
R3159(SECAM-Curr.) Feed in a SECAM-L red raster test pattern with 75% saturation
(ratio burst: chroma = 1 : 2.2) into the AV1 socket and record
it.Terminate the Service Test Programme, disconnect R3031
from L5001 and reassemble the drive mechanism.
1.6 Chassis Board � Standard Sound (AL)
Test equipment / aids: Frequency Counter, AF Millivoltmeter, AF Generator, Colour Generator, branded Video Cassette.
Service work after replacing the RP-Head, L5603 or IC7007: Adjustment no. 1, 2
AdjustmentPreparationAdjustment Procedure
1. Erase Frequency,Frequency counter:.......................wire bridge 9034 (Head)With F5603 (BIAS R) set the frequency to 70kHz ?10kHz.
F5603(BIAS R)Record
1.1 Bias,R3618 (BIAS)AF millivoltmeter:..........................BIAS1 or BIAS2 (R3606)Set the voltage drop across R3600 with R3618 (BIAS) to
Record.15mV.
rms
Check the frequency response.
1.2 Frequency�Feed in a CCVS signal via EURO-AV1 socket, contact 20.The voltage ratio of 400Hz to 8kHz must not be higher than
Response Test �Feed an audio signal of 200mVrms (480mVPP) from the AF1:0.7 or 0.7:1 (?3dB). If the voltage ratio exceeds these limits,
generator to the EURO-AV1 socket, contact 2 or 6.the bias must be altered:
�Make a recording of 400Hz and 8kHz each of 1 min at least.To increase the playback voltage at 8kHz: Reduce "BIAS".
Afterwards play back these recordings (MONO).To reduce the playback voltage at 8kHz: Increase "BIAS".
�Connect an AF millivoltmeter (oscilloscope) to EURO-AV1
socket, contact 1 or 3.
2. Playback Level forAF millivoltmeter:............EURO-AV1 socket, contact 1 or 3Set output voltage with R3160 (PB-Lev.) to 0.5V?50mV.
rms
Mono VCR,AF generator (1kHz / 0.7Vrms):
R3160(PB-Lev.)........................................EURO-AV1 socket, contact 2 or 6
Feed in a CCVS signal via EURO-AV1 socket, contact 20.
Play back the self made recording (Normal Play).
for Stereo VCRCall up the Service Test Programme (see page 2-4).Observe the instructions for Level 62 (see page 2-6).
Call up Level 62 (see page 2-4).Terminate the Service Test Programme (see page 2-4).
k 3 - 4GRUNDIG Service |
ACEC
GRUNDIG
