Sharp C-2890EES, Руководство по обслуживанию

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6
AK - 45
CHASSIS
1.INTRODUCTION
11AK45 is a 50Hz colour television capable of driving 24” + CRT sizes (beginning from 24” 16:9 up to
33”).
The chassis is capable of operation in PAL, SECAM, NTSC (playback) colour standards and multiple
transmission standards as B/G, D/K, I/I’, and L/L´.
Sound system output is supplying 2x10W (10%THD) for left and right outputs of 8ohm speakers.
TV supports FASTTEXT. It is possible to decode transmissions including high graphical data.
The chassis is equipped with three full EuroScarts; only one of them supports RGB input, one
headphone output, one FAV input, one SVHS input (via SCART)
2.TUNER
The hardware and software of the TV is suitable for tuners, supplied by different companies, which are
selected from the Service Menu. These tuners can be combined VHF, UHF tuners suitable for CCIR
systems B/G, H, L, L´, I/I´, and D/K. The tuning is available through the digitally controlled I
2
C bus
(PLL). Below you will find info on one of the Tuners in use.
General description of UV1316:
The UV1316 tuner belongs to the UV 1300 family of tuners, which are designed to meet a wide range
of applications. It is a combined VHF, UHF tuner suitable for CCIR systems B/G, H, L, L’, I and I’. The
low IF output impedance has been designed for direct drive of a wide variety of SAW filters with
sufficient suppression of triple transient.
Features of UV1316:
1. Member of the UV1300 family small sized UHF/VHF tuners
2. Systems CCIR: B/G, H, L, L’, I and I’; OIRT: D/K
3. Digitally controlled (PLL) tuning via I
2
C-bus
4. Off-air channels, S-cable channels and Hyperband
5. World standardized mechanical dimensions and world standard pinning
6. Compact
size
7. Complies to “CENELEC EN55020” and “EN55013”
Pinning:
1. Gain control voltage (AGC) : 4.0V, Max: 4.5V
2. Tuning voltage
3. I²C-bus address select : Max: 5.5V
4. I²C-bus serial clock : Min:-0.3V, Max: 5.5V
5. I²C-bus serial data : Min:-0.3V, Max: 5.5V
6. Not connected
7. PLL supply voltage : 5.0V, Min: 4.75V, Max: 5.5V
8. ADC input
9. Tuner supply voltage : 33V, Min: 30V, Max: 35V
10. Symmetrical IF output 1
11. Symmetrical IF output 2
3.IF PART (TDA9885/86)
The TDA9885 is an alignment-free single standard (without positive modulation) vision and sound IF signal
PLL.
The TDA9886 is an alignment-free multistandard (PAL, SECAM and NTSC) vision and sound IF signal PLL
Both devices can be used for TV, VTR, PC and set-top box applications.
The following figure shows the simplified block diagram of the integrated circuit.
The integrated circuit comprises the following functional blocks:
VIF amplifier, Tuner and VIF-AGC, VIF-AGC detector, Frequency Phase-Locked Loop (FPLL) detector, VCO
and divider, Digital acquisition help and AFC, Video demodulator and amplifier, Sound carrier trap, SIF
amplifier, SIF-AGC detector, Single reference QSS mixer, AM demodulator, FM demodulator and acquisition
help, Audio amplifier and mute time constant, I
2
C-bus transceivers and MAD (module address), Internal
voltage stabilizer.