Video Ckt; Black Diagram Of Video; Mm1375Xd Block Diagram - Acer V551 Service Manual

Acer V551 (new) CRT Monitor Service Guide

2. Video CKT

(1) Black Diagram of Video

R
G
(From PC)
VIDEO
B
CONTRAST
(From uC IC801)
Beam Current
(From FBT)
H-clamp
(From IC201)

(2) MM1375XD Block Diagram

The function block below represents one of the threevideo amplifiers in the MM1375XD
along with the contrast, gain adjust and brightness contrals. The Contrast Control is DC-Level
(0 ~ 4 V) operate attenuator which controls the video gains of the three channels (R, G, B)
simultaneously The Gain
Adjust Control, which is also a DC-level operated circuit, provides a 6 dB gain adjustment to
each channel. During the retrace period, the Clamp Comparator will charge or discharge the
clamp capacitor by comparing the external brightness (clamp+) level with the video output DC
level thus that the brightness level is maintained.
Preamp CKT
MM1375XD
IC101
ABL CKT
Clamp CKT
Q316
Q 205
Confidence and Property
Chapter 2 Circuit Operation Theory
DC Restore
CKT
Cascode CKT
Q101,110
Q103,111
Q105,112
Brightness CKT: Q203
Change Mode Blanking:Q202
V-blanking CKT: Q201
Spot Killer CKT: Q202
R
G
B G1
9