Chassis Board; Adjustment Procedure - Grundig GV 94 HiFi Bedienungsanleitung

Adjustment Procedures
Adjustment Procedures
GB

Chassis Board

View of Solder Side
Test equipment / aids: Two-channel oscilloscope with 10:1 probes, voltmeter, colour generator, test cassette, branded video cassette
Service works on replacement of ...
... the tape drum: Adjustment No. 1, 2
... IC304: Adjustment No. 1, 2
... Tuner/Modulator: Adjustment No. 3
Adjustment
1. Headwheel Oscilloscope:
Position Indicator Channel 1 (trigger): ................................................ TP183
Channel 2: ..................................... Euro-AV1-(19) socket
Test cassette, playback
When the playback picture appears touch the K button
three times immediately. The automatic adjustment mode
will start.
2. Still Picture Feed a CCVS signal into the EURO-AV1 socket and
Optimisation record it in Standardplay mode.
Play back this recording and press button Ó .
3. Crosstalk VR631 Feed in a standard test pattern with "Stereo" sound modulation.
– right channel 1kHz, 30% modulated
– left channel not modulated
Oscilloscope: ................................ EURO-AV socket Pin 3
Press the "Audio" button on the remote control so often as
is necessary to make "L R" appear in the display.
3 - 2
TP182 TP183
C3016
IC301
Preparation
Tuner
TN -3
PWB
VR631
SEPARATION

Adjustment Procedure

• Automatic adjustment: The adjustment process is
indicated on the display. The meter counts from "P: 0:01"
to maximum "P: 2:55". The meter will stop at the set value.
The value can then be adjusted manually.
• Manual adjustment: Use the buttons Ü or * to set the
head switching pulse to 6.5 ≥ 0.5 lines before the vertical
sync pulses.
Channel 2:
1V/div 50≤ s/div
Video output
6.5 ≥ 0.5H (lines)
Channel 1:
2V/div 50≤ s/div
Head switching pulse
Press button to leave the test mode. The indication
"P:– : –" appears for a short time on the display.
With buttons C / D set the still picture according to your
best personal impression.
With VR631 adjust for minimum amplitude.
GV 94...
V-sync
GRUNDIG Service