ITC222 Convergence & Geometry
P
UBLICATION
O
VERVIEW
This publication is intended to detail procedures for returning the convergence of an ITC222
instrument to manufacturing specifications and assuring the performance of Autoconvergence.
Procedures to do so begin the manual. Informational and tutorial sections are included only as
Appendix items.
The manual details convergence procedures and steps required to perform them. It is arranged by
procedures and listed in the order they should be performed. Typically these procedures depend
on the individual repair issue. Begin with the Overview, first determining what repairs are required,
then proceed through the manual as it is written. Geometry is critical to convergence. Care should
be taken to understand how geometry affects convergence. If at all possible geometry should not
be disturbed especially if Sensor Calibration runs successfully.
While the procedures given in the main Overview may look simple do not mistake the complexity!
Alignments are sensitive and interactive. Make certain it is understood which procedures are
required and leave other alignments alone. Changing alignments that do not need to be done will
always complicate the procedures required.
Appendix A, Chipper Check, fully explains how to use Chipper Check to transfer existing
convergence EEPROM files to a replacement SSB module. Appendix B, Field Service Menu,
documents how to use the Field Service Menu for those technicians not yet familiar with its
operation. Also included in the Appendix are tables for screen size dimensions and decimal to
fraction conversions.
G
ENERAL
I
NFORMATION
This training material assumes a knowledge of the current Thomson television chassis ITC222.
The material has been prepared using general reference to geometry and convergence operation
with specific reference to the ITC222. Standard procedures and operation may change over time
so in all cases Electronic Service Data for the instrument should be consulted for the most accurate
component values and voltages.
EEPROM’s or
Electrically Erasable Programmable Read Only Memory
, are sometimes referred
to as NVM’s or
NonVolatile Memory
devices. They are the same device simply called by different
names.
Chipper Check© is Thomson, Inc PC based diagnostic and alignment system.