V20 Chassis Technical Training
and Troubleshooting Guide
4-5
cuitry, IC2V01, is required for the sub picture signal.
Sub picture video is applied to pin 7 of IC2V01 and
sub picture horizontal sync to pin 5.
The internal circuitry in IC2V01 determines the pro-
grams rating and forwards the information over the
SUBCCD-SDA line to the Control µPC. If the sub
picture program rating changes, IC2V01 alerts the
µPC over the VCHIP-PB line and then sends the new
program rating over the SUBCCD-SDA line.
Parallel Inputs/Outputs
Of course there are parallel (single purpose) inputs and
outputs to the µPC. Most of the inputs are status in-
puts. Parallel Inputs are listed in
Table 1
, giving the
input abbreviation, description (purpose) and the source
of that specific signal.
Parallel outputs are mainly control logic, or signals
such as On-screen display signals. Parallel outputs
are given in
Table 2
, along with the description and
the destination for that signal.
IC7A00 Microprocessor Inputs
PIN# ABBREV.
DESCRIPTION
SOURCE
6
SD2
Sub Tuner Sync
Í
Q1B32
7
SD1
Main Tuner Sync
Í
Q1A32
20
AC-OFF
Indicates Power Loss
Í
(KD-2)
Í
(KF-6)
Í
PC9A21-3
46
SHORT
Short on DC supply
Í
(KE-13)
Í
Q9B01/D9B01/DB902
47
XRAY
Excess HV/Beam Current
Í
(KE-15)
Í
(KH-5)
Í
IC5A02-13
92
AFT1
Main Tuner AFT voltage
Í
TU1A01-20
93
AFT2
Sub Tuner AFT voltage
Í
TU1B01-20
94
VBLANK-IN
Video is blanked (deflection loss).
Í
D5A13
95
VSYNC
Vertical Sync from Doubler
Í
(EB-7)
97
HSYNC
Horizontal sync from Doubler
Í
(EB-6)
( ) = Connector
Table 2: Parallel Inputs
Summary of Contents for VS-50111
Page 2: ...x ...
Page 4: ...x ...
Page 6: ...V20 Chassis Technical Training and Troubleshooting Guide ii ...
Page 10: ...V20 Chassis Technical Training and Troubleshooting Guide 1 4 ...
Page 20: ...V20 Chassis Technical Training and Troubleshooting Guide 2 10 ...
Page 38: ...V20 Chassis Technical Training and Troubleshooting Guide 5 6 ...