Heathkit ETA-3400 vs. ETW-3400 confusion?

@Tom & All, "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." Fair enough, and it's as good a suggestion as anything heard so far. But again, you're confusing the (very easily confused) model names.. The ET-3400 and ET-3400A are the original "trainer" kits. These are the main computer module, with a calculator-style keyboard, 7-segment LED display, and either 512 bytes or 1KB RAM memory. I believe that the later 'A' version also includes the 4MHz crystal-controlled system clock upgrade, in addition to the larger RAM size. The expansion modules are confusingly called out as ETA-3400 (note, not ET-3400A) and ETW-3400. It's these latter two distinctions that are the cause of my (and apparently, much) confusion. But your suggestion that the 'W' substitution refers to a factory-wired unit makes good sense, at least in this case - because my ETW-3400 seems to have been factory built. It doesn't have any of the tell-tale signs of kit assembly. For instance, it appears that the board has been wave soldered and washed of flux. The rest of the workmanship gives the same impression of factory-quality assembly. So maybe that's all there is to it? The ETA-3400 is kit form, and the ETW-3400 is factory built? On Mon, Jun 6, 2016 at 10:19 PM, Tom Watson <tsw-cc at johana.com> wrote: