CIRCUIT OVERVIEW (continued)
ABL CIRCUIT
ABL (Automatic Blanking Level) and ACL (Automatic
AKB CircuitContrast Level) are circuits designed to protect the CRT
INVDD
510against over-current of electron beams that will burn
a.c.9 11the screen phosphors. Both circuits limit the current
MIRROR
flowing to the screen. For 27-inch sets, the beam
CASCODE
TDA6120Q4xINOUT
current is limited to 1.5 mA. For 32 and 36-inch sets
12
V6CC1xOUTCthe beam current is limited to 1.6 mA. The ABL controls
13
MIRROR1xOUTthe current by affecting the black level and the ACL by
1x0.7 pF
INOUTOUT1xOUT4xlimiting the contrast.
IN7OUTM
The ICX2200 Video processor has two ABL modes of
CURRENT
VIN- 2+INPUToperation: Picture only and Picture/Brightness. The first
J 5mACASCODE
one only affects the contrast level. This first mode is
1348also called ACL. The second option affects Contrast and
RC-RC+ VIN+GND
Brightness. This option is a mix of ABL and ACL. Both
options are selected by software. The Picture only mode
is fixed.
The factory adjust of cut off is based on this system.
The processor moves the reference pulse according toAUDIO PROCESSING
the level indicated on the cut off register. When the
STEREO MODULE
reference pulse is moved, the AKB system moves the
There are five different Audio sources: Antenna/Cable,
black level of the signal. This is the way it adjusts the
Aux video, S-Video, Rear Computer, and Front Computer/
white balance at low contrast.
Front Video.
The Tuner/IF section processes the Antenna/Cable
signal. It then passes as Composed Audio to the audio
processor to be demodulated.
MicroProcessor IIC Bus
Stereo Module
PW R MUTE
Rear Jack Packs91026273
10SDASCLSCL
R-INSDA
VIDEO/AUX11
8
L-IN393962SPKR-R
ROUT TAUX1-RLSOUT-RR-IN
1641
405
R-INLOUT TAUX2-LLSOUT-LL-IN7
S-VIDEO14
L-INIC801
221-01145
22
COM PUTER-IN
REAR20
(SVGA/NTSC)L-IN
A/V SwitchAudio Processor7
SPKR-L
ICX2900IC1400Front Jack Packs
221-01053221-01127
6
COM POSITER-IN
VIDEO FRONT 4
L-INTransistor Variable
Audio Output Monitor
Vol, Bass, Treble,
Balance, SoundRite,AUX-R
Antenna/CableSEQ
To Rear Jack Pack
AUX-L
TUNER/IF COMP-IN
COMPOSITE AUDIO
SR23 - 923-035093-5CS - SERVICING |
ACEC
