Function Description - Mitsubishi DPLUS 74SB -BKA Service Manual

Function Description

Pin No. Pin Name
18 Red Video Out
19 Green Video Out
20 Blue Video Out
21 R Out
Ref
22 ABL
23 Clamp Pulse
24 H Flyback
Schematic
7-39
Description
Video outputs of the LM1269. The ideal
driver for this part is the LM246X CRT driver
family, which has the necessary gain of 26
dB or 20 V/V.
A 0.1 µF capacitor must be placed close to
this pin for decoupling the internal V
pin may be used for an external voltage
reference with proper buffering.
The Auto Beam Limit control reduces the
gain of the video amplifier in response to a
control voltage proportional to the CRT
beam current. The ABL acts identically on
all three channels. ABL is required for CRT
life and X-ray protection.
This input accepts a standard TTL or CMOS
input. A positive signal activates the clamp
pulse for DC restoration of the video input.
The AC coupling capacitors at the video
inputs are used for holding the DC
correction voltage, eliminating the need for
additional capacitors.
H flyback is an analog signal input from the
monitor horizontal scan. The LM1269 is able
to generate an accurate blanking pulse in
the video outputs from this input. The
horizontal flyback from the monitor must be
a clean signal, with no ringing or other noise
on the signal.
. This
Ref