On Screen Display; Service Settings - Grundig STR 100 microSAT Serviceanleitung

Schaltungsbeschreibungen / Circuit Descriptions
the baseband signal BB CIC1060-(5), or the CCVS signal CIC1060-(3),
and pass the respective signal on to the Scart decoder socket.
2
Under I C bus control, the audio-video switch CIC1220 assigns the
audio output pins (15), -(16), -(17), -(18), -(19), -(20) to the correspond-
ing VCR, decoder, or TV Scart socket. Via the impedance converters
CT1230 and CT1260 the video outputs CIC1220-(23), -(26) are
connected to the Scart VCR socket or Scart TV socket.
The CCVS inputs of the Scart sockets, VCR and decoder pin 20, are
switched to the output of the TV Scart socket by the corresponding
switching voltages from the processor CIC1400.
3.2 Sound Signal Path
From video CIC1170-(18), the baseband signal is subjected to a
bandpass of 5...10MHz and is then fed to the mixer input of the audio
signal processor IC1250-(3). This IC contains a PLL-controlled VCO
2
(controlled via the I C-bus) and a mixer which converts the input
frequency to 10.7MHz. The IC1250 contains two PLL FM demodulators
which are provided with a noise reduction system. With the main
sound, this system is bypassed. The mixer output pin 5 is connected
to two narrow-band ceramic filters (130kHz) and one wide-band
ceramic filter (280kHz) which supply the FM signal to the input pins 9,
11, 13. Additionally, the following functions are switched in this IC via
the I 2 C bus:
- type of sound: Mono 50µs / J17 / Mono and Stereo according to
Panda Wegener
- switching voltages: Video deemphasis PAL / Lin.
The Audio L/R outputs are connected with the inputs of the audio matrix
CIC1220-(7), -(8). The audio matrix is responsible for the necessary
adjustment to the Scart sockets and is changed over analogously to the
video matrix.

4. On Screen Display

Together with the microcomputer CIC1400, the "On Screen CMOS
Character Display" CIC1280 makes it possible to display a full page
with separate background and to superimpose information on the
screen. For this purpose the CIC is fitted with a programmed Character
ROM containing 128 characters.
The quartz oscillator Q1280 for the background of the full page and for
generation of the sync signals operates at a frequency which is 4 times
the PAL colour carrier frequency.
2 - 4
The integrated Display RAM of the IC allows to display 12 lines of 24
characters each. The character codes are entered into this RAM via the
2
I C bus and the STB lead. Separate registers determine the position of
the display. Each character consists of a 12x18 dot matrix the vertical
and horizontal size of which is determined by the line scanning pattern.
The width of the character is determined by the LC oscillator
CIC1280-(8), -(9). This oscillator operates at a frequency of 7MHz and
is synchronised by the field and line pulses from pins 13 and 14 for on
screen display.
For menu display without transmitter signal, CIC1310-(6) pulls the VS
lead to "Low". Consequently, CIC1400 switches the OSD chip to
"blue".
Counters which are triggered by the line frequency and the LC
oscillator are used for addressing the Display RAM. The integrated
Character ROM converts the character codes to pixels.
The transistor network CT1273, CT1271 clamps the CCVS signal in
the on screen display switch CIC1280-(20) to the black level of the
OSD data signal.
4.1 Sync Pulse Generation
For synchronisation of the display data the CCVS signal from the video
matrix CIC1220 is routed to the sync CIC1290-(6). This IC separates
the H-sync and V-sync signals and passes them on to the inputs of
OSD CIC1280-(14), -(13).

Service Settings

Note on Replacement of EEPROMS CIC1420:
In the memory CIC1420 the basic satellite data (deviation etc.) are
stored. In the case of repairs solder a programmed EEPROM with the
part number 72008-668.38.
STR 100 microSAT
GRUNDIG Service