Apple 1 ICs

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Apple 1 ICs

 Hello! I am new to this site and registered since I am building a Newton NTI replica. It will probably take some time to get it finished, but I have been able to pull a few components from two 1976-1977 boards, which was a good start! I am still missing most of the sockets, so if someone have a few C8414 or C8416 I am interested.

 Anyway, this post was not going to be about me, but about the Apple 1 ICs. I have Mike's BOM and have been collecting based on that. Yesterday an Apple 1 was sold at Christies auction house, and I was able to grab pictures of that machine. One thing I noticed is that it did not use 74161, but has 9316PC (Fairchild) in its place. After checking a few of the Apple 1's in the registry, it seems like many of the pre-NTI have this component in the 74161 socket (the pictures are boarderline with respect to resolving the number, but its a 4-character number not 5).  As for the NTI boards I have not been able to determine the number, but it looks like a Signetics component.

 

 So was this a common replacement or did it come from Apple that way? Was the 9316 also used in the NTI boards?

 

The Apple 1 that just got sold:

 

Edit: Sorry for the double post. The first time it didn't appear for some reason, but pressing "back" on the browser reloaded the edit page so I could post the first post. Unfortunately it appeared as a new topic. I have no idea on how to delete the empty double post here..

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Yes the "byte shop" boards

Yes the "byte shop" boards (first 100 made) used the 9316 Fairchild Mil-Spec part.  Many of the parts on those boards are surplus Mil-Spec.  The later board (NTI) generally did not use Mil-Spec, but regular Signetics 74161 chips.

 

Are you building an NTI or byte-shop style?   I may have some spare 9316 chips.  I have to check my stash to see if I still have them.  I sold a bunch to a member here in Italy a year or two ago, so I have to see what extras I have.

 

Cheers,

Corey

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Ok. Interesting. I noticed

Ok. Interesting. I noticed the computer from Christies also had an 7451 instead of a 7450. Plus one of the Signetics 2504V were changed to a 451DS/NH0025CN.

 

My board is a NTI board so I am trying to get it as close to that as possible. If they used Signetics 74161, that is what I want.  I have alot of ICs from two boards, but many were the wrong types... (no wonder) So if anyone requires other 74xxx components from 1976... :-P

 

The Signetics 25xx series seems to be hard to find.

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The correct chip for a byte

The correct chip for a byte shop is a Fairchild 7451.

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Apple-1 chips

kakemoms wrote:

Ok. Interesting. I noticed the computer from Christies also had an 7451 instead of a 7450. Plus one of the Signetics 2504V were changed to a 451DS/NH0025CN.

 

No, it was not changed. 

The DS0025CN is a two phase MOS clock driver. The 2504v a shift register. Different and correct.

You can have a look to my interactive Apple-1 image: https://apple1registry.com/interactive/apple-1.html 

Only the SPRAGUE 2400uF was changed, but the original capacitor was included in the sale. The original one just need some reforming. 

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Ok. I took the list at http:/

Ok. I took the list at http://www.willegal.net/appleii/a1bom.htm as my source for Apple-I components. It didn't mention the 7451, but I see that the MOS clock driver is on it. Do you know wheter the NTI board also uses 7451?

 

Thank you for the interactive Apple-I board. It makes it easier to see what components goes were.. and which way.

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Yes, Signetics N7451A is used

Yes, Signetics N7451A is used for NTI boards.

 

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Fun fact:   For some strange

Fun fact:   For some strange reason my Leaper 1A TTL tester can’t test Fairchild 7451, they all fail even when good, but works fine with Signetics 7451A.  

 

 

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