Matsui 1410R, Service Manual

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The RC networks are used to convert the modulated pulse output to a DC voltage level. Some of these settings can be preprogrammed in the
memory for all channels as a personal preference (PP). Mute is controlled internally on the mC during automatic station search or when the signal
received is interrupted (detected via the IDENT signal on pin 16).
- Service: If pin 7 is connected to earth when the set is turned on from the IR, the unit will go into Service Default Mode (see Chapter 8).
- INT/EXT and mute on programme 0. The microcontrollers have a pin for switching to external (pin 7 on the TMP47C634 and pin 8 on the SAA5290)
via transistors 7876 and 7877. This signal is added to the signal from SCART pin 8 so that either of them can be used to switch to external.
On units without SCART, this signal is used for muting the sound and picture on programme 0.
On the SAA52XX models, this line is also an input line so that the microcontroller knows if the unit is on external. This way, the correct video signal
is switched on the TXT and the sound is not muted on external, even if there is no pilot signal.
- EEPROM bus 12C memory (pins 39 and 40 on the TMP47C634; pins 49 and 50 on the SAA52XX); The microcontroller is connected to non-volatile
memory IC7685 (EEPROM) via bus 12C. Personal preferences (PP) and channel data are stored in the memory. The system can memorize 79
channels (with the data on tuning voltage, band and system) and the personal preferences.
- Standby (pin 19); The Standby switching signal is on pin 19 of the mC. If the Standby signal is “low”, it reduces the start-up voltage of oscillator pin
36 on the TDA836X, thus cutting the line voltages.
- Control and options keypad; The decoding principle is different depending on the unit. On the TMP47C634, it decodes a matrix between pins 11,
12 and 13 while on the SAA52XX, it only checks to see if the pin is earthed. The TMP47C634 also checks for diodes 6603, 6604 and 6605 via pin
14 on the microcontroller (see options table on diagram).
The SAA52XX reads the options via pins 14 and 52, which will be “1” or “0” depending on the components (2690, 3600, 3650 and 3657).
- TXT: The SAA5290 has an internal teletext decoder. The following functions have been programmed on the software: TXT input/output, show,
freeze, temporary cancellation, clock, subcode, zoom, index, flof, page +/-, X/26 and 8/30 packet decoding (station identification and start-up page).
Synchronization is received from the HOR FLY and VERT FLY signals, as is the OSD (this means that if the video signal is lost, the TXT does not
become unsynchronized). The teletext information is extracted from the video signal inserted on pins 23 (internal video) and 24 (external video) via
condensers 2635 and 2636.
Pin 27 corresponds to the NIL control signal, which pulse switches transistor 7640 and keeps the picture from interlacing when applied to the
vertical deflector.
All remaining circuitry (oscillator, RGB output, fastblanking, etc.) is shared with the microcontroller.
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