If that were the case here, the correct translation for "Sein Name war nicht Geissler sondern Geißler" would be "His name was Geissler rather than Geissler." Which is clearly wrong, as the first makes sense but the second doesn't. (I agree though that the noun "Geissler tube" is it's own thing and indeed language specific.)

Is your argument that "If a literal translation of a sentence doesn't make sense, then the translation for each word must be wrong?" If so, that's trivial to find counterexamples for:

It's not hard to find Japanese sentences that would literally translate to English as roughly: "O I think it's so cute that you say 'I' (僕) instead of 'I' (私)."

Claiming therefore that translating 僕 and 私 each to the word "I" is always wrong is nonsensical.

If you are making some weaker claim that excludes my example, please fill me in because I couldn't think of one.