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I just received my first two Texas Instruments Clear Case calculators and like to understand why they were manufactured.

Is it about the missing 3D modeling in the 1970's or about the injection molding optimization? Any ideas?

Thanks and Regards,


Yes, that's exactly why it is done. It's not as important now do the sophisticated 3D CAD, but it's sometimes still done since it is still a useful verification.

After the clear cases are made and it is verified that the design meets the requirements, the texturing is added to the mold. It is then not possible to make good clear cases again because:

  1. With the textured mold, the resulting case would not really be optically clear
  2. After non-transparent material has been molded, trying to mold transparent material will usually result in the molded part having residue of the non-transparent material, unless you mold and discard a large number of items to flush it all out.

That reminds me of a few classic Macintoshes that floating around the collector community like that. One sold on Ebay last year for around $500 I think.

Joerg, I'm sending you images of a clear SR-10 case containing SR-11 innards.

I have a clear case Newton 110. The engineer at Apple I asked about it said it was to help check component fitment inside the case.

That's fortunately/unfornately not the whole truth. I just read about it this week - a larger batch of clear 110s has been manufactured and were available for purchase by employees, good customers and I think as well on a developer conference. They were manufactured for the looks, the development has long been finished before the production run.
Nice to have, but not too rare (guesstimates are talking about a four-digit number of clear 110s).

Congratulation !!

So you were between the ones looking at that auction ?

It went from 43 US$ to over 700 US$ in the last hour ....

nice items, congratulation again !


Nice TI's Joerg, but alas they aren't HP's ...

my 71B

my 28S

HP clear cases

BTW, there is a clear cased 71B for sale on ebay right now - it ended without a bid and is now relisted (I am not the seller, but it's someone I know - item 290647978271) - the price is reasonable, i'm not sure why no-one is bidding.

Cheers, Keith