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..
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
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.
The correct chip for a byte shop is a Fairchild 7451.
[quote=kakemoms]
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.
[/quote]
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.
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.
Yes, Signetics N7451A is used for NTI boards.
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.