Heathkit ETA-3400 vs. ETW-3400 confusion?

[Tom Watson]

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).