6 Jun
2016
6 Jun
'16
8:19 p.m.
In following this thread, and taking in my "vast" Heathkit knowledge, I can only
assume that the addition of a 'W' in the model number is to indicate a WIRED (at
the factory) Heathkit.
This may mean that the ETW-3400(a) is a wired version of the ET-3400(a).
The difference that shows between the 'a' and non 'a' version is the space
for four ram chips in the upper left visible corner of the PC board. The non-a version
can have up to 4 ram chips (for a total of 512 bytes), but the a version has two 1024x4
chips, but only 512 bytes are available.
Hope this answers some questions.
(I have an ET3400-a version).