Apple 1 Replica with date correct chips - Please comment

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Joined: Sep 13 2016
Posts: 9

Greetings from San Francisco, new member here so thank you in advance for the input and discussion on my topic. My Apple 1 board has many correct chips and dates codes but still searching for the most correct ones (the big one will be to replace the 6502 with a MOS white ceramic). For those of you who might have time, please open the two attachments and examine the current chips and date codes. I would be interested in which chips should be updated to reflect a 1976 pre-NTI board. Also, what week in 1976 would be the cut off for a correct pre-NTI board? The table below has an X in the last column when I think that chip should stay and a "?" to indicate a possible change.

I'm also aware that this type of replica that has all correct chip makers and exact date codes for 1976 only appeals to a very small group as most are satisfied with just a working replica. But I am hoping that those who like this type of challenge will help me. Thank you all!

AttachmentSize
apple 1 ic C-D.jpg1.05 MB
apple 1 ic A-B.jpg1.02 MB

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Joined: Oct 9 2011
Posts: 1046
Re: Apple 1 Replica with date correct chips - Please comment

I was thinking for a bit on how to respond to your post. There is some complexity to what you are asking. Only the first 50 Apple-1 have some sense of consistency to the chips/date codes and yes they are all 1976, as a matter of fact pretty much July and earlier 1976 date codes. Later pre-NTI may have dates codes up to the end of 76. NTI can have date codes into mid 1977.

Some of the date codes vary in the post 50 preNTI units.

I'm not sure I understand some of your columns, are you listing the chips you have now? It seems this way since CM2140 was never used on the original A-1. FYI: Pre-NTI boards are pretty consistent in that most of the chips are Fairchild not Signetics and some are 9NXX and some aren't. So that is another indicator that your listing is what you have for your replica since pre-NTI did not use Signetics 74S257.

So are you looking to replicate a Byte Shop early 50 or later 50? If I provide you date codes of an actual unit, you could go pretty insane and broke trying to track down the exact replacements.

Cheers,
Corey

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Joined: Sep 13 2016
Posts: 9
Re: Apple 1 Replica with date correct chips - Please comment

Hello Corey and thanks for your comments! I completely agree that this is a complex subject and for the vast majority of collector enthusiasts, not something that they are much interested in. And maybe wisely so! I have read posts of members asking the question of why even do this. I believe you may have commented on the “why” in another post and for those few of us with this goal, it is indeed the “hunt” and the “challenge” of exactly duplicating the Apple 1 board. But of course, which board eh?

Regarding this challenge, we are indeed lucky that we have a couple of boards that are reproduced at such a high accuracy and finish. This one fact alone allows us the opportunity to pick which hobby goal one wants to engage in. I had settled on my target representation of a pre-NTI board to be that in general, of a 1976 example, not necessarily the first 50 or the later 50. From your observation that the later boards in 1976 included date codes to the end of the year, it seems to me that would be the best target board to replicate and prevent a total loss of insanity. Thanks for pointing this out and that alone helps me focus on which chips to next hunt down.

Sorry to confuse you with my table, but the columns labeled Chip #, Maker and Date is what is currently populated on the board. I have been in the computer business for many years, but I don’t solder so I purchased this board already built and working. I thought it would be an excellent start with my ultimate project of correct manufactures and date coded chips. Sounds like a need to loose as many Signetics as possible.

I’m trying to envision what it must of been like stuffing the boards in 1976 (apparently not in a garage). They must have bought the needed chips in bulk so yes they would have been of the same date range. But what if they had run low and their source was temporarily out of stock? If they scrambled to find another supplier, could they have had older stock resulting in date codes of 1975, 74 or even 1973? It is in this spirit that I am attempting to build an “exact” replica, not to mirror any one known example. I want to look at the finished board and think - it could of looked just like this!

No question that I will have to refinish the two PROMS with Apple logos and I see much work has already been done in this area by other members as well.

Respect,
Theodore