Magnavox MTV-51 Manuel de service télécharger pdf (Page 20)

SERVICING (continued)

FA - SERVICING 3-6

DIGITAL COMB FILTER

The IC2400 is the digital comb filter for NTSC-U format

it is a 1H, 2L Digital comb filter.

It separates luminance (Y) and chrominance (C) signals

from NTSC system composite video signal by using 2

horizontal (H) lines and delaying 1horizontal line on

memory.

This logical comb filter reduce color dot interference

and realizes high performance Y/C separation.

COMB FILTER CRITICAL SIGNAL

On the Pin 10 (Fsc) color sub carrier signal tuned to

3.58 Mhz for chrominance and luminance separation.

If this signal is not present the next problems could

be happened:

a) Color flicker

b) Chroma beat

c) Luminance signal noise

VIDEO OUTPUT

The RGB signals are applied to the IC5100, which is the

video RGB output.

IC5100 is triple Amplifier with fix gain equal to 51, op-

erating at 9 Mhz of Bandwidth with small signal. It uses

one +Vcc equal or less of 200 DC Volts. AKB option is

not used for this model.

Using LR array the output is connected to its respective

Cathode

SCAN VELOCITY MODULATOR

This signal comes from directly from Video Processor

IC2200.

Three stages for signal are:

1: Class A NPN Amplifier

2: Complementary symmetry Driver

3: Complementary symmetry output Amp

Impedance coupling network connects to SVM coil in

CRT assembly.

YUV SWITCH PROVISION

FA chassis also has a provision to support an additional

YUV input thru IC2902, 74HC4053AP,but this is only a

provision. This IC is a 6x3 DEMUX controlled by control

signal sent by IC6000, MICOM. The outputs point to

rear jack’s YUV (Normally Closed inputs).

1 2 ... 15 16 17 18 19 20 21 22 23 24 25 ... 55 56

Commentaires sur ces manuels

Pas de commentaire

Magnavox MTV-51 Manuel de service Page 20

Commentaires sur ces manuels

Produits connexes et manuels pour Télévisions à tube cathodique Magnavox MTV-51