GV 67 …, GV 69 …
Adjustment Procedures
GRUNDIG Service
7
GB
Adjustment Procedures
1. S-VHS-Board – Luminance (SH)
Test equipment / aids: Oscilloscope (>50MHz) and Frequency Counter with 10:1 Test Probe, Digital Voltmeter, Colour Generator.
Service work after changing the …
… S-VHS Board: –
… Family Board, headwheel or IC7600: Adjustment no. 10
Adjustment
Preparation
Adjustment Procedure
Oscilloscope: ............................................................. MP
6
AV recording (100% white test pattern, 1V
PP
, S-VHS)
Oscilloscope: ............................................................. MP
2
AV recording (100% white test pattern, 1V
PP
, S-VHS)
Oscilloscope: ............................................................. MP
4
AV recording (100% white test pattern, 1V
PP
, VHS, Standard
Play)
Frequency Counter: ................................................... MP
3
AV recording without input signal (VHS)
AV recording without input signal (S-VHS)
Frequency Counter: ................................................... MP
3
AV recording (100% white test pattern, VHS)
AV recording (100% white test pattern, S-VHS)
Oscilloscope: ............................................................. MP
52
AV recording (S-VHS)
Oscilloscope: ............................................................. MP
6
Play back white test pattern (VHS self made recording)
Play back white test pattern (S-VHS self made recording)
Oscilloscope: ............................................................. MP
7
Play back 100% white test pattern (S-VHS self made recording)
Play back a100% white test pattern (self made recording, VHS).
Measure the voltage at MP
37
with the digital voltmeter and
note it down.
Connect IC7800, Pin 4 with ground (GND) and Pin 5 with +5V.
Digital Voltmeter: ........................................................ MP
39
Connect IC7800, Pin 4 with +5V and Pin 5 with ground (GND).
Digital Voltmeter: ........................................................ MP
38
Feed in a red raster test pattern.
Insert a record/play cassette.
Call up the Service Function with the remote control:
– Press button "CODE" repeatedly until "
CODE ----
" appears on
the display.
– Enter
4 9 3 4
in this order and confirm with button
G
.
1. Record Level,
R3487
(REC)
2. EE Level,
R3637
(EE)
3. White / Dark Clipper
White Clipper,
R3515
(WC)
Dark Clipper,
R3521
(DC)
4. Sync Value
VHS,
R3503
(SV-VHS)
S-VHS,
R3509
(SV-S-VHS)
5. White Value
VHS,
R3507
(WV-VHS)
S-VHS,
R3513
(WV-S-VHS)
6. Luminance Writing
Current, R3765
(YWV)
7. Playback Amplitude
VHS,
R3543
(PBA-VHS)
S-VHS,
R3545
(PBA-S-VHS)
8. Dropout Level,
R3723
(DP)
9. S-VHS-PB Detection
Reference Level
– S-VHS
R3791
(REFS)
– VHS
R3795
(REFV)
10. FM Reference
Level for "ACC+"
(Automatic Contour
Control)
With R3487
(REC)
set the amplitude to 400mV
PP
.
With R3637
(EE)
set the amplitude to 2V
PP
.
100% Luminance Signal
A
B
5
µ
s/cm
With R3515
(WC)
set the overshoot A to 195% of the luminance
signal.
With R3521
(DC)
set the overshoot B to 65% of the luminance
signal.
With R3503
(SV-VHS)
set the frequency to 3.8MHz.
With R3509
(SV-S-VHS)
set the frequency to 5.4MHz.
With R3507
(WV-VHS)
set the frequency to 4.62MHz.
With R3513
(WV-S-VHS)
set the frequency to 6.67MHz.
With R3765
(YWV)
set the FM signal to 250mV
PP
.
With R3543
(PBA-VHS)
set the amplitude to 400mV
PP
.
With R3545
(PBA-S-VHS)
set the amplitude to 400mV
PP
.
With R3723
(DP)
set the signal as shown in the oscillograms
below.
10
µ
s/cm
With R3791
(REFS)
adjust the voltage so that its level is 0.35V
higher than that measured at MP
37
.
With R3795
(REFV)
adjust the voltage so that its level is 0.25V
higher than that measured at MP
37
.
Remove the connections to ground and +5V.
Press button "CODE". Enter the figures
5 2
in this order and confirm
with "CODE". The message "
ADJUST
" appears on the display.
On successful completion of this adjustment the display shows
"
READY
".
Terminate the Service Function by pressing button
A
or by
disconnecting the VCR from the mains.
