Model 7475A 
Section V 
SECTION V 
PRODUCT HISTORY 
5-1.  INTRODUCTION 
5-2. 
This section describes the differences between earlier models of the 
HP 
7475 
and the latest version documented 
in 
this 
manual. These earlier models are identified by their serial prefix number, 
and 
the 
date codes on their printed-
circuit assemblies (PCAs).  For ease of reference this section is divided into two major topics; History of Serial Prefix 
Numbers 
and 
History of Printed Circuit Assemblies. 
5-3.  HISTORY OF ASSEMBLIES BY SERIAL PREFIX NUMBER 
5-4. 
Table 
5-1 
is 
a quick-reference table 
that 
lists, by plotter serial prefix number, the assemblies 
that 
differ from 
those documented in this manual. Also referenced are Item Numbers under which these differences are described in this 
section. 
5-5. 
Table 
5-2 
lists 
the 
assemblies 
that 
are described under each Item. 
5-6. 
Knowing the serial prefix number of 
the 
plotter, the user 
can 
see 
in 
Table 
5-1 
which assemblies are documented 
in 
this 
section. 
In 
Table 
5-2 
the user 
can 
see 
if 
more 
than 
one change 
has 
been made to the assembly 
in 
question 
and 
which Items 
in 
this section to refer to. 
Table 
5-1. 
Assemblies by Plotter Serial Prefix Number 
SIN 
PREFIX  ASSEMBLIES  ITEM 
2325A 
Al 
MainPCA 
See PCA History 
Chassis Assembly 
5 
NOTE 
Assemblies  designated  with 
an 
asterisk 
(*) 
denote  changes 
made during the plotter production cycle. 
Table 
5-2. 
Item Description 
ITEM 
ASSEMBLIES 
5  Main Chassis 
Pinch Roller Arm (Left) 
5-7.  HISTORY OF PRINTED CIRCUIT ASSEMBLIES 
5-8. 
Hewlett-Packard's printed-circuit assemblies have three major identification features: 
a. 
Part 
Number. 
All PCAs 
having 
the 
same 
part 
number are directly interchangeable. 
If 
a PCA is revised 
in 
any 
way 
that 
makes 
it 
non-interchangeable with previously issued PCAs, a  new 
part 
number 
is 
assigned to the 
revised  PCA. 
b. 
Revision 
Letter. 
This letter identifies the most recent revision to 
the 
etched circuit pattern. The original issue is 
identified  with 
the 
letter 'A'. 
If 
the master artwork for  a  PCB is revised 
in 
order to  alter performance or 
manufacture,  the revision  letter is changed to  the next letter in the alphabetical  sequence. 
5-1