Daewoo DTR-14D3VG, Руководство по обслуживанию

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20
No Name Description
46 VERT DRIVE + The vertical drive has a current output. The output is balanced which ensures
47 VERT DRIVE - a good common mode behavior with temperature and makes the output signal
less sensitive for disturbances.
48 IF INPUT The PLL frequency range is 32-60MHz with corresponding VCO frequency
49 64-120MHz.
The IF input impedances is 2K
Ω
⁄ in parallel with 3pF and matches the required
load for commonly used SAW filters.
A DC coupling is allowed, so no series capacitors between SAW filter and IF
input are necessary.
50 EHT/OVERVOLTAGE The input range for EHT tracking is 1.2V - 2.8V, for a compensation of +/-5% on
PROTECT INPUT vertical and / or EW. The tracking on EW can be switched on/off by HCO. The nominal
voltage of pin 50 for no compensation is 2V.
The EHT feedback signal must be filtered in order to prevent disturbances in vertical
and/or EW deflection. A compromise has to be determined for tracking speed on
normal EHT variation and ripple immunity.
ZOOM FUNCTION Special linear zoom facilities on both Vertical and East-West gives the possibility to
adapt the picture size for both 16:9 and 4:3 screens. When zoom is used, the
geometry correction remains correct in both vertical and horizontal direction. Using
VSC(Vertical Scroll) the (expanded) picture can be shifted up and down. By
programming the vertical slope, VS, subtitles at the bottom part of the picture can be
made visible while the picture position at the top of the screen remains fixed (subtitle
mode).
51 VERTICAL This pin requires a capacitor to ground of l00nF +, - 5%. Short connection to the ground
SAWTOOTH pin of the TDA884X is required. Important: For this capacitor, a type with good tem
CAPACITOR perature behaviour, long term stability and low leakage must be chosen.
Change of the capacitance value due to temperature and/or aging leads to a propor-
tional change in vertical amplitude. Tolerance of the external capacitor can be com-
pensated by means of the vertical slope adjustment of I
2 C bus function VS.
The charge current can be fine tuned with =/- 20%.
The optimal sawtooth amplitude is 2.9V and is determined by the external capacitor
and charge current. For R = 39K
Ω
at pin 52, the vertical slope VS = 1F and field fre-
quency = 50Hz, the charge current is 16µA. For 60Hz the charge current is increased
by 20%. The sawtooth bottom-level is 2.3V.
The vertical retrace time is determined by the discharge current of 1mA and lasts about
5 horizontal lines.
52 REFERENCE This pin requires a resistor to ground.
CURRENT INPUT The optimal reference current is 100µA. which is determined by this resistor.
53 AGC The AGC capacitor value is 2.2µF and has been defined for an optimal
DECOUPLING compromise between AGC speed and tilt for all AGC modes
CAPACITOR (negative/positive modulation).
54 TUNER AGC This output is used to control (reduce) the tuner gain for strong RF signals.
OUTPUT The tuner AGC is an open collector output which is acting as a variable
current source to ground.
55 AUDIO The pin requires a capacitor to ground that defines the deemphasis time constant.
DEEMPHASSIS The DC and mute level is 3V.
The signal is internally connected through to the Audio switch.
56 DECOUPLING This pin requires a capacitor of 10µF connected to ground.
SOUND The pin acts as a low pass filter needed for the DC feedback loop.
DEMODULATOR