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There are two basic
patterns.
1. Earlier units proceed in pure sequential order starting from zero or
a specific starting number as follows: 0 for models 10, 24
1000
for 1, 2, 3, 4, 5, 8, 8B, 9, 10B, 15, 16, 18, 19, 20, 20B, 22, 25, 26,
27, 28, 29, 32, 105, 110, 115, 115B, 120, 120B, 125, 150, 240, 250,
250M, 500, 510M, 1200, 2010, 2015, 2200, 2240, 2245, 2270, 2440, 3300,
3600, 3800, 4060, 4100, 4220, 4230, 4240, 4270, 4415, 4430 10000
for 7, 7C, 7T 100000 for 2235, 2250B. Also some later units have
a "J4" suffix which indicates the unit is equipped with a universal
power transformer. Inside a terminal strip allows the unit to be
switched between 100V, 120V, 200V, 220V, 240V voltage sources.
2. Later units are sequential but within only each
production run. Example: 93N040085.
In this case "04" indicates the fourth
production run and the last four digits represent the sequential
production number within this run.
When this method was adopted a letter was added to indicate the
region of the world for which the unit was
primarily intended to be sold: A = Australia C = Canada
E = Europe K = Far East N
= unknown, usually found in Europe P = Post Exchange
U = USA. It appears that most if not all non - USA models include
an external voltage selector which allows usage anywhere in the world.
Later a two digit prefix
was added to replace the manufacturing date stamp that was formerly
found on the chassis. The first digit indicates the year, we believe the
second digit indicates the six week period within the year.
The following models overlap both numbering systems: 112, 140, 1030,
1040, 1060, 1070, 1090, 2215, 2215B, 2225, 2230, 2235B, 2275, 2325,
4300, 4400. When the change was made the production run number started
at the correct number (indicating they were keeping track). |