Apple 1 44-pin connector pinout?

The only expansion connector reference I know about is the schematics included in the Apple-1 operation manual.

regards,
Mike Willegal

Mike WIllegal wrote: The only expansion connector reference I know about is the schematics included in the Apple-1 operation manual. regards, Mike Willegal

Apple 1 Manual

Page 11, shows the 44 pin connector (J3).

Just something to be aware of, to make a compatible edge connector is a little more complicated than it seems.   The original Apple-1 puts unregulated voltage which is important for the Cassette adapter reliability.   The -12V and +12V are actually more like -16v and +16V.  The ACI circuit loses reliability when you don't have -16v for the unregularted -12v on the edge connector.  I modified my Replica-1 with a voltage regulator setup to provide the needed voltages to allow the Replica-1 and a stock Apple-1 ACI to work all from a single 20V wall wart.

Corey986 wrote:

Just something to be aware of, to make a compatible edge connector is a little more complicated than it seems.   The original Apple-1 puts unregulated voltage which is important for the Cassette adapter reliability.   The -12V and +12V are actually more like -16v and +16V.  The ACI circuit loses reliability when you don't have -16v for the unregularted -12v on the edge conne

I take it that you aren't using a 1:1 replica PCB, then? his is good to know--I certainly wasn't aware of it. I'm not surprised about unregculated voltage, though. Some Apple II specs also do not show specific regulation in mind for the 12V current supplies. It is always a good idea to supply a VR on your add-on itself, if you need specific voltages. I tend to keep 7805 VRs on hand, in general. 

I suppose I could make a new diagram in KiCAD if there is any immediate need, and fully upated information that people want on it. 

Yes I'm talking about a briel Replica-1

On my real Apple-1 and my Mimeo, everything just works as is because well that's how it was designed.

kb0wwp wrote:

Corey986 wrote:

Just something to be aware of, to make a compatible edge connector is a little more complicated than it seems.   The original Apple-1 puts unregulated voltage which is important for the Cassette adapter reliability.   The -12V and +12V are actually more like -16v and +16V.  The ACI circuit loses reliability when you don't have -16v

Sigh. Congratulations on finding a way to persuade me. :P

IDK when I will do it, but it is now on my list. If someone beats me to it, then, good for you, and thank you for saving me the work. 

Corey986 wrote:

Just something to be aware of, to make a compatible edge connector is a little more complicated than it seems.   The original Apple-1 puts unregulated voltage which is important for the Cassette adapter reliability.   The -12V and +12V are actually more like -16v and +16V.  The ACI circuit loses reliability when you don't have -16v for the unregularted -12v on the edge conne

Made a slight "senior moment mistake" here.  I'm actually using a 28V AC wall wart which also provies a center tap (something I had found at a surplus place in the bay area).  Not a 20 V DC, I was confiused it with another project.  Also -16V is bare minimum for the ACI, -20 is better.

Cheers,

Corey

Corey986 wrote: The original Apple-1 puts unregulated voltage which is important for the Cassette adapter reliability. The -12V and +12V are actually more like -16v and +16V. The ACI circuit loses reliability when you don't have -16v for the unregularted -12v on the edge connector.

I'd like to understand this better. The ACI uses an LM311 comparator, and from what I can tell from the data sheet, the circuit would be quite insensitive to the value of the V- supply. The inputs are biased to 2.5 V (with a small amount of hysteresis), and the common-mode voltage extends down to 0.5 V above the negative rail. Even using ground for V- should work. So I don't understand why there should be any difference between ground, -12 V, and -16 V on the comparator V-.

Cheers, Peter

The issue is generally that a modern digital audio source is much lower in potential volume than the potential of a real tape player.  If you follow all the threads on Applefritter relating to this topic you will see that an normal ACI uses much less than max volume.  An iPod uses max volume.  Using ground instead of the unregulated -12v is possible with a tape player nearly at maximum.