Product History; Introduction; History Of Assemblies By Serial Prefix Number; History Of Printed Circuit - HP 7475A Service Manual

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