Heathkit ETA-3400 vs. ETW-3400 confusion?

drlegendre . drlegendre at gmail.com
Tue Jun 7 22:47:15 CDT 2016

I've been reviewing the 'conversion' document, found here:


Which describes how to modify the ET-3400/A to mate with the ETA-3400 accy
unit. For some reason, a number of details - pictorials, it seems - are
missing from the document.

All of the missing details seem to involve modification and connection of
an 'RF shield' component, which might refer to a copper tape strip which is
part of the ET-3400 package. Apparently, the they intend for a wide copper
strip to interconnect the ground planes of the two chassis..?

My sense is that the info was left out as it's unnecessary to achieve
correct operation.. more of a "the FCC made us do this" sort of thing. Can
anyone comment on the omission, and any importance it might have?


(My complete Heathkit 3400 series document set is here:


It includes all of the scanned 3400 materials I have collected, and I
believe it is complete, less the BASIC programming course materials. All
other documents, including the self-taught courses should be present.
Please advise if anything is missing, or if you can supply the BASIC course


On Tue, Jun 7, 2016 at 3:58 PM, drlegendre . <drlegendre at gmail.com> wrote:

> Hey, thanks for the catalog link. It confirms that the 'W' designation
> indicates factory-wired units, in the case of both the trainer and the
> accessory unit. But note the difference in assembly costs between the
> ETW-3400 and the EWA-3400 accessory, I'm surprised that the latter would
> take any more time to build than the former, but I'm sure they had their
> reasons.
> And it appears that the $47.00 chip option is for the extra 3K of SRAM
> that the accy. board can hold (for the max total of 4K). Both the tiny
> BASIC and monitor ROMs are standard equipment, and included in the regular
> price - or at least they were in 1979.
> On Tue, Jun 7, 2016 at 7:06 AM, william degnan <billdegnan at gmail.com>
> wrote:
>> I am wrong.  The W means assembled in the factory apparently.
>> http://heathkit.garlanger.com/catalogs/1979/Heathkit_Catalog_845.pdf
>> For another $47 you could by the chipset for either the W or T versions.
>> Sorry about that.
>> b

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