Prescriptions d'alignement / Adjustment Procedures
GRUNDIG Service
3 - 5
2.2 Family Board – Frontend (FV)
Test equipment: Oscilloscope with 10:1 Test Probe, Voltmeter, Colour Generator
Service work after replacing the Tuner: Adjustments no. 2
Adjustment
Preparation
Adjustment Procedure
1. Vision Demodu-
lator Circuit
1.1 PAL/SECAM,
L5725
1.2 SECAM-Band 1,
R3748
2. Delayed AGC
Voltage, R3742
Feed in 38.9MHz / 100mV
PP
into the tuner output
1701-(17).
Voltmeter: ..................................................... IC7701-(20)
EE-mode.
Connect the plug contacts 1912-(15), "PSS" – SECAM active,
and T7723 (collector), "SB1" – band 1 active, to ground.
Feed in 33,9MHz / 100mV
PP
into the tuner output
1701-(17).
Voltmeter: ..................................................... IC7701-(20)
EE-mode
Feed in a PAL white test pattern with sound carrier (without
sound modulation, UHF-range, Ch24, 67dB
µ
V aerial signal)
into the warmed-up VCR.
Oscilloscope: ......................................... Tuner 1701-(17)
EE-mode.
Set the voltage with F5725
(AFC)
to 2.5V
±
0.2V.
Set the voltage with R3748
(BAND I)
to 2.5V
±
0.2V.
Set the amplitude with R3742
(AGC)
to 550mV
SS
+0/-50mV
approximately.
2.3 Family Board – Video/Chroma (VS)
Test equipment: Oscilloscope with 10:1 Test Probe, Frequency Counter, Colour Generator
Service work after replacing the Family Board: Adjustments no. 3
Adjustment
Preparation
Adjustment Procedure
1. Frequency
Deviation Sync
Value, R3057
2. Writing Current
2.1 PAL Chroma
Writing Current,
R3038
2.2 SECAM Chroma
Writing Current,
R3042
3. FM-Reference
Level Adjustment
for ACC (Automa-
tic Contour
Control) plus
Studio Quality
Set frequency counter with R3057
(Sync. Frequ.)
to 3.8MHz
±
10kHz.
Set Chroma signal with R3038
(CHROMINANCE WRITING
CURRENT PAL)
to 71mV
PP
(-12.5dB of the FM-signal).
Set Chroma signal with R3042
(CHROMINANCE WRITING
CURRENT SECAM)
to 42mV
PP
(-17dB of the FM-signal).
Disconnect IC7051-(2) from +5V.
The machine automatically records the input signal and
then plays it back. On completion of the adjustment the
video recorder switches to stand-by.
AV recording (do not feed in an aerial signal).
Frequency counter: ............................................ 1911-(2)
Connect IC7051-(2) to +5V.
Oscilloscope: ...................................................... 1911-(2)
Feed in a PAL red raster test pattern with 75% saturation
(ratio burst : chroma = 1 : 2.2).
AV recording.
Feed in a SECAM red raster test pattern with 75% saturation
(ratio burst : chroma = 1 : 2.2).
AV recording.
Load a video cassette and select the input signal source.
Call up the Service Function with the remote control handset:
– Press the button "CODE", enter the code number
4 9 3 4
and press the
G
button.
– Press the button "CODE", enter the code number
4 9 3 8
and press the
G
button.
