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Early Parallel Card question

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ried:
I recently picked up an early Parallel expansion card which seems to be from 1982 and differs significantly from other cards that I have. The earlier card has plastic parallel ports and is part number 820-4017-A, while the later card features the usual metal ports and is part number 820-4027-A. Notably, the early card also lacks the FCC ID, which is usually present and covered with green paint on later cards and subsequent versions.

Anyone else have one like this? Gallery: https://imgur.com/gallery/apple-lisa-parallel-cards-profile-9zsk8ZP

AlexTheCat123:
I've never seen anything like that before! I wonder if it's some sort of prototype?

ried:
Could be. The part number 820-4017-A does not seem to show up in Google search results.

stepleton:
I can't spot any difference. If you have one, stick the cards in a flatbed scanner and superimpose the scans; toggle/fade layers and see if you spot a difference. Could just be down to a trace or two.

ROM contents probably differ; use BLU or a programmer to read them out and compare.

blusnowkitty:
The only difference that stands out to me (other than the obvious P/N changes and DB differences) is that the early board appears to be a two layer board, while the production board is a 4-layer with inner ground or voltage planes.

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