Block Diagram - Daewoo DTH-14Q1FS Service Manual

B. VIDEO BLOCK
1. TV/VIDEO SWITCHING
1) SWITCHING BLOCK DIAGRAM
µ-COM
(I701)
TV(H)
/VI(L)
2) CIRCUIT OPERATION
•After going out to the #8 of I501, the detected signals go into the #10 of I501through 4.5MHz BPF(Band Pass
Filter, Z502) : TV SIGNAL.
•The external VIDEO signals from JV01(or JV02) go into the #14 of I501 : VIDEO SIGNAL.
•Output pulse from the #33 of the ¥-COM(TV:HIGH, VIDEO:LOW) go into #1 of I501 through a buffer(Q504 and
Q507).
•According to the input pulse of the #1, TV/VIDEO switching circuit let out the video signals to the RGB generator
block inside I501.
2. OUTLINE AND OPERATION OF 3-SYSTEM AUTO SWITCHING
1) SWITCHING BLOCK DIAGRAM
2) CIRCUIT OPERATION
•If 50[Hz] detected. #21 of the I501 goes down to LOW level. This out goes into the Q506 (and #27 of the I701),
and then X501 oscillates (#1 and #2 of the I701 are deactivated.).
33
1
SIF
Filter
I701
µ-COM
1
NTSC-M
2
PAL-M
7.6V
Q506
27
9V
R766
28
R774
I501
LA7688
VIDEO
8
DET
VIDEO
SWITCH
10
14
R,G,B OUT
I501
LA7685J
X502
41 VCO
X503
X501
9V
21 50/60
Q502
17 COLOR
/KILLER
Q705
13
9V
Q503
EXT.VIDEO
(JV01/JV02)