Daewoo 2898ST, Service Manual

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No Name Description
43 PHI-1 FILTER The loopfilter connected to pin 43 is suitable for various signal conditions as
strong/weak and VCR signal.
This is achieved by switching of the loopfilter time constant by changing the
PHI-1 output current.
Via I2C bus FOA/B, different time constants can be chosen, including an
automatic mode which gives optimal performance under varying conditions.
44 GROUND To this pin are connected the IC-substrate and horizontal output.
45 EAST-WEST DRIVE The EW drive is a current output.
The output is single-ended and is fed directly to the EW-input terminal
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 2
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 1.2 ~ 2.8V, for a compensation of +/- 5%
PROTECT INPUT on vertical and/or EW.
The tracking on EW can be switched on/off by HCO.
The overvoltage protection is activated when the voltage on pin 50 exceeds
3.9V typical.
51 VERT This pin requires a capacitor to ground of l00nF +/- 5%.
SAWTOOTH The optimal sawtooth amplitude is 3.5V and is determined by the external
CAPACITOR capacitor and charge current.
The sawtooth bottom-level is 2V.
52 REFERENCE This pin requires a resistor to ground.
CURRENT INPUT The optimal reference current is 100 . which is determined by this resistor.
53 AGC The AGC capacitor value is 2.2 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 not used.
DEEMPHASSIS
56 DECOUPLING This pin requires a capacitor of 10 connected to ground.
SOUND The pin acts as a low pass filter needed for the DC feedback loop.
DEMODULATOR