Zenith A19A02D Service Manual page 5

The GA series chassis was developed for Sentry 2, screen
sizes 19" through 27" stereo and mono models. The chas-
sis is a single sided printed circuit board. One board is
used for the 19" and 20" connected sets. A second board
is used on the 25" and 27" isolated sets. During the
manufacturing process, the EAROM is programmed for
any added features. Output jacks will be added to the
board to accommodate the different features: Video/
Audio In, Non MTS Stereo, and MTS Stereo.
The GA series chassis features three IC's for all signal,
sync and sweep processing. ICX2200 handles all of the
audio/video, sync and sweep drive processing. IC6000
is the microprocessor and IC6001 is the EAROM memory.
The keyboard and IR detector are tied directly to IC6000.
IC2100/2101 handles the vertical sweep.
At turn on, voltages for the vertical and video output
OVERVIEW
circuit are derived from the sweep circuit.
MODEL INFORMATION
The GA chassis is comprised of three (3) categories. GA-
1, GA-2, and GA-3. Each category represents the screen
size and different model feature levels.
The GA-1 chassis had five module variations which are as
follows:
9-1869 (19/20V, Mono) Main Module w/o Jack Assy.
9-1870 (19/20V, Non MTS Stereo) Main Module w/o Jack
Assy.
9-1871 (19/20V, MTS Stereo) Main Module w/3 Jack Assy,
CM150
OVERVIEW
A-18577.
9-1950 (19/20V, Mono) Main Module w/2 Jack Assy, A-
18577-01.
The GA-2 chassis has three module variations which are
as follows:
9-1789 (25V, Mono) Main Module w/o Jack Assy.
9-1790 (25V, Stereo) Main Module w/3 Jack Assy, A-
18577.
9-1791 (27V, Non MTS Stereo) Main Module w/3 Jack
Assy, A-18577.
9-1831 (25V Stereo) Main Module w/3 Jack Assy. A-
18577.
9-1831 (25V, Stereo) Main Module w/3 Jack Assy, A-
18577.
The GA-3 chassis also has three module variations which
are as follows:
9-1996 (25V, MTS Stereo) Main Module w/5 Jack Assy,
A-18785.
9-1997 (27V, MTS Stereo) Main Module w/5 Jack Assy.
A-18785.
9-1998 (27V, MTS Stereo) Main Module w/5 Jack Assy.
A-18785.
1-1
GA - GENERAL