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GRUNDIG CUC 7851
Service and Special
AFC-Reference
The AFC control voltage influences the setting
Functions Cont'd
of the station (fine tuning) on HF-reproduction
and on station search mode.
IR-Data Programmer
With this menu and with the IR-Data Program-
The Automatic Frequency Control is activated
mer 2 it is possible to store a maximum of 99
only if the desired programme position is
programme positions with the data for the TV
marked with the station identification AV.
norm, Peri, 6-place station identification and the
-
fine tuning frequency.
The programmer AP transfers only channels
-
and 4-place station identifications.
Call up via the Menu Info Centre --> Special
Functions --> IR-Data Programmer.
Emergency Data
If necessary the emergency data can be read
On activation of the AFC function a voltage level
out from the EPROM. See "Service Adjust-
is read out from the IF-amplifier which is used
ments".
as a reference for AV-programmes and on
Service Adjustments
station search.
Changing the Sharpness
Adjustment of the Screen Grid Voltage U
Call up the Info Menu --> Picture Menu -->
Sharpness, and change the value with
.
-
-
Colour Registration
The colour registration function allows to
compensate for differences in the delay
-
between the Y-channel and the chroma
-
channel.
-
With the Menu guide call up the
"Colour Match" menu via the Service
Programme, Info Centre --> Special
-
Functions --> Service --> Code 8500.
-
With buttons
correct the delay so
that the Y chroma signals coincide.
Adjustment of the Bridge Coil L511
White Balance
-
Call up the White Balance menu via the
-
Info Centre --> Special Functions -->
Service --> code 8500.
-
With the
buttons set the VG
(amplification green) and VB
-
(amplification blue) values so that the
white rectangular area in the middle of
the picture becomes achromatic. Store
-
with OK.
-
Tuner AGC
The automatic Gain Control offers two possibili-
ties of adjusting the delayed automatic gain
control voltage for the tuner:
Adjustment of the Line Sharpness
1:
Feed a standard test pattern at a
With the focus control
channel in the upper range of the UHF
control panel adjust the lines in the north-south
band into the aerial socket. The RF
direction for maximum sharpness.
should be 1.5mV (64dBmV).
TV receivers with focusing panel:
Call up the "Tuner-AGC" menu via the
Subsequently, with the focus control
Service Programme Info Centre -->
focusing panel, adjust the lines in the east-west
Special Functions --> Service --> Code
direction for maximum sharpness.
8500, select "automatic" and confirm.
Repeat if necessary.
The control processor will set the
correct value for the delayed gain
Attention: For measurements on the focusing
control voltage.
panel use only sufficiently insulated measuring
2:
Feed in a standard test pattern at a
cables and test probes with adequate electric
UHF channel as high as possible to
strength (eg. 100:1).
the aerial socket.
Call up the "Tuner-AGC" menu, Info
Videotext (VT) Matching Adjustment
Centre --> Special Functions -->
At the time of delivery the control R378 is set to
Service --> Code 8500, select "manual"
the lowest high-frequency emphasis. If, despite
and confirm.
a perfect aerial signal, character faults occur,
With the
buttons tune the TV
turn R378 slowly until the character errors
station so that noise just begins to
disappear. Do not turn R378 any more as the
appear in the picture. Then tune in the
error rate may increase again.
reverse direction until the picture just
During this adjustment page 199 must always
becomes noise free. Store with OK.
be selected anew so that it is read in anew
making it possible to evaluate the error rate.
Picture Geometry and Picture Position
Adjustment via the Remote Control Handset
For accurate adjustment of the picture a test
generator or standard test pattern should be
used. For raster corrections it is also possible to
use the integrated test pattern.
Tune the tuner precisely at a
1:
Call up the Geometry Menu via Info
programme position.
centre --> Special Functions --> Service
Call up the AFC Reference Menu via
--> code 8500.
Service Programme --> Info Centre -->
Special Functions --> Service --> Code
2:
If a standard test pattern is not
8500 --> with the menu guide and
available, move the bar with the cursor
activate with OK.
buttons to the menu item "Test
Pattern On".
Attention: Start always with the "V-middle"
adjustment otherwise the other vertical deflec-
tion parameters would defy correct geometry
adjustment.
SG
"V-Middle" Adjustment with a Colour Test
Feed in a test pattern
Pattern
With the remote control adjust the
screen brightness so that the grey
-
Select the "V-Middle" menu. The upper
areas just become dark.
part of the picture is coloured, the
Switch the receiver to AV operation.
lower part is black and white.
Connect a high-ohmic voltmeter
-
With the
(series resistance 220kOhm approx.)
broken lines on the left and on the right
to the test points R, G, B and deter
of the indication "V-Middle" upwards or
mine the highest voltage.
downwards so that they coincide with
With the control U
on the picture
the line separating the coloured part
SG
tube panel set the highest voltage
and the black/white part of the picture.
level to approx. 10V.
-
Continue with the picture geometry
adjustment via the menu and store.
V-Middle Adjustment with a Video Generator,
Call up the Geometry Menu via Info
eg. Grundig VG 1000
Centre --> Special Functions -->
Service --> Code 8500. Set the
-
Feed in the convergence test pattern
horizontal amplitude to minimum.
with standard colour bars via RF.
Connect one test probe of a dual-
-
Call up the "V-Middle" menu.
beam oscilloscope to the collector of
-
With the
the transistor T572.
setting so that the G-Y vector (orange
Connect the second test probe
area in the centre of the picture) is just
between the diodes D502 and D503.
covered.
Adjust the coil L511 so that the pulse
-
Continue with the picture geometry
width of both oscillogrames is
adjustment via the menu and store.
the same.
The "line shift" alignment influences the line
phase setting. Before this adjustment set the
horizontal amplitude to minimum and if neces-
on the adjustment
sary correct the raster position with the "Shift
Plug". With button
the centre of the raster. Re-adjust the horizontal
amplitude with the test pattern.
on the
3:To store this adjustment, move the bar to
"Terminate with store" and confirm with OK.
The picture geometry is set to the last stored
value whenever the receiver is switched on.
Reset:
Under the menu item "Reset" an average data
set from the ROM is stored. After inadvertent re-
adjustment during servicing, these basic values
can be re-loaded at any time. For this, move the
yellow bar to "Reset", press the OK button. By
pressing the "AUX" button the picture geometry
is set according to this "Reset" values.
4:With the i button return to the normal menu.
2
or
buttons move the three
or
button change the
Socket
Diagram
or
move the picture into
Interference Diagram
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