Questions for Ex Heath Types.

[Milton Ferguson]

   As a collector of Heathkits, I find a need for lists identifying the
various Kits and their associated part numbers. To this end I have found
many useful lists online providing valuable information for collectors.
A summary of my finds may be useful to other Heathens.

    A listing of ALL the Heath products, identifying them by Model
number and Date, is of basic importance. Such a list might be generated
from a complete set of Heatkit Catalogs if you have such (I don't). Even
then, some numbers would be missed since they are generated for special
situations such as mod kits. I know of NO truly comprehensive list.
However, I find most useful the Heathkit Product Index available at
W0IMJ's site. While not complete, this list is truly great and he should
be congratulated for this effort.

   A second valuable source of Heathkit Model Numbers is WB9JJA's
Heathkit matrix. With fewer entries, this list is derived from a
collection of Heathkit Catalogs indicating the first and last years the
product appeared. This list provides more detail on the individual
entries.

   When it comes down to detailed part numbers, there are two sources.
For all but semiconductors, the most useful is David Wilson/John
Parker's Master Part List. Unfortunately,  this list does not cover
unique parts for kits produced after about 1965. The list is apparently
a copy of an Original Heath Factory document listing by Part number,
brief description and price (at that time). The part numbers are not
referenced to the individual Kit Model Numbers. Much desired, would be a
later edition covering subsequent models.

   For semiconductors you can't beat the Heathkit Semiconductor Cross
Reference list (http://www.d8apro.com/heath3.htm). This list is
frequently updated, lists all Heath Semiconductor Part numbers (Prefixes
56/57/411/417/442/443/444) and indicates available alternates. Truly a
gold mine of information!

   Oh Yes! I was going to ask some questions.

   At the factory, when making up the kits, many parts were put in bags
or envelopes. In particular, for individually packaged ICs (for
instance), the package had TWO numbers on it. Typically 443-XXX followed
by a second number usually 172-XXX. What is the significance and/or
purpose of the second number? Is there a reference for it anywhere?
Perhaps it connects the part(s) to a particular kit (although, why not
use the model number?).

   The assignment of numbers to the parts used in a kit was apparently
done on an as-needed basis. Rather than set up a series of numbers
covering all 1/2 Watt resistors (for instance), the parts were assigned
as needed. Consequently, the listings of a basic part number (such as
10-XX for a particular type of resistor) are not arranged in any logical
sequence. This probably had the advantage of limiting the number of
drawings required (presumably each part required a separate spec sheet)
but allowed for adding new numbers when a previous part became obsolete
or unobtainable.

   In closing, I implore anyone who has better references than above, to
make them available. Thqanks.

               73s,


                    Milt. Ferguson

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