September 1976 Issue of Interface Age

The famous advertisement for the Apple 1 first appeared in the September 1976 issue of Interface Age, not the October issue as is widely believed. This issue also has an article on a 6502 dis-assembler, which was written by Steve Wozniak and Allen Baum, with source code listing included. Apparently, this code was available on an Apple-1 Cassette. I don't know if this code is available on the internet (maybe Vince Briel's Replica 1 includes this utility?). I just received this magazine today, so I have not read the whole article yet...

More info on the datanetics keyboard

Wendell Sander informed me today that he believes the first Apple II keyboards may have been manufactured for Apple, by Datanetics, Inc. He sent me this early Apple II keyboard schematic scan from the 1979 Apple II Reference manual.

I also contacted Steve Wozniak yesterday, but he said that if he has any info on the Datanetics, that it is probably somewhere in storage. I also asked him about the modifications, but he did not know / doesn't remember, if the electrolytic cap was original or not.

UPDATE: from Cameron Cooper: "John, the early Apple II keyboards were definitely made by datanetics. You can see one of Mike's on this page: Apple II Keyboard

From what I gather around the keyswitch patents, it looks like Apple may have acquired either Datanetics or some of their technology."

Thanks Cameron!

Datanetics Keyboard V

Datanetics Keyboard IV

Datanetics Keyboard III

Datanetics Keyboard II

1976 Datanetics Keyboard (Serial # 0010)

Discouraging start to the day...

Well, I don't know what the heck happened here, but my keyboard decided not to function today. It was working fine last night... I burned a new BASIC EPROM chip, plugged in the firmware card, powered up the board, and now the keyboard is not working. Some keys work: 1, A, S, D, E, H, J, K, L, Q and that's about it. Most of the other keys do not work. My keyboard has always been flaky, and restarting usually worked. But today, no deal!

UPDATE: I hooked the keyboard up to an Apple II Plus and verified that the problem is the keyboard.

So...

AVR time

Apple-1 BASIC Firmware Card

Another EUREKA moment... well, sort of...

I spent some time over the last few weeks building an expansion card with Apple-1 BASIC programmed on an EPROM. I am able to see the code starting at address $E000. I had initially included a 7404 inverter on the card (as in the picture) but it is not needed and the wiring has all been disconnected and the chip removed. I will post details on how I built this card soon... I am still trying to get BASIC to actually run.

After a little more research it looks like I'm going to be adding a 7410 3 input NAND gate, so that I can AND and invert VMA * clock(00) * J3 pin 11 and the output will be connected to /CE on the EPROM. When all 3 inputs are active HIGH, the output will be LOW, thus activating EPROM.

UPDATE Feb/3/2010: After looking at the schematics again, I guess I don't need to add any gates.

I have been trying to get BASIC to run using the following commands without any luck:

Start system

Clear screen, Reset

enter: E000R

output: E000: 4C@

At this point, I can't do anything except for a reset. No keyboard input is accepted.

4C is the first byte of BASIC. I should be getting the ">" prompt according to the manual.

=====

I also tried the following:

Start system

Clear screen, Reset

enter: E000.E000R

wait until the "\" appears (as stated in the manual when loading from cassette)

output afterwards, these are the last 3 bytes I see, plus the cursor: E_\@

enter: E000R

output: E000: 4C@

A14F Rectifier Diode

I've received quite a few emails on where to find the A14F rectifier diode, and my answer has always been: http://www.talonix.com/shop/item.aspx?itemid=8334

It turns out talonix.com doesn't have them and I do not know where to find them -- if anyone does, please let me know. (I obtained my A14F in a trade for a 2519N with an Apple 1 owner who has long since, sold his board, and I have lost contact with him, so I'm not sure of the source).

News tidbits

If you are interested in obtaining your own Apple 1 reproduction kit, you might want to check out willegal.net to see Mike's progress on the Apple 1 he is reproducing. Hopefully we'll all be able to purchase boards and kits soon!

I was also informed today that Cameron C. is starting a new community for Apple 1 enthusiasts : www.apple-1.org Cameron is still working on the site but stay tuned.

There are 2 guys working on wire wrapped Apple 1s.

I am working on short videos of my progress -- although my camera sucks, I'll see what I can make available (probably on youtube because of blogger's video size limit).

Second PCB Bug

Mike Willegal had posted a question on applefritter.com awhile ago for someone to check/verify that pin 12 of the Address Decoder / 74154 was connected to ground. From the scans he was working with, he found that pin 12 was not grounded. I checked the board that came with the kit and could see visually, that pin 12 was grounded. At the time I assumed there was nothing wrong with the non-kit board I have, but I assumed wrong. Earlier this week I removed the DIP socket where the 74154 resides, because I wanted to check for solder-bridges under the DIP. I then placed multimeter leads (set to Ohms) from pin 12 to ground and verified that pin 12 is not connected to anything.

I resoldered a new DIP socket, and added a jumper from pin 12 to the ground side of the closest ceramic capacitor. Unfortunately, I am still picking up a 1+ volt signal on ground... more to come on this when I know more.

BTW, it appears at quick glance that the schematics omitted showing GND on each component.

PCB Bug

For all of those who purchased an Obtronix board (not the kit) on ebay several years ago, there is a bug on this board. I can't say we all have the same board, but the board I have is missing a trace on D7 (74161) from pin 7 to pin 10. This bug was causing characters to repeat after a reset. I soldered a jumper wire across these pins, and the repeating chars stopped. This bug was found by Mike Willegal (willegal.net). I verified these pins were not connected by using a multimeter.

DS0025CN vs DS0026CN

I tested the DS0026CN chip last week. Although you can enter a program which the system appears to accept, displaying the bytes in memory afterwards shows completely different data. Why bother? Because the DS0025CN is pretty hard to find. I believe I paid $13 USD for a single chip!

Mounting everything to Plywood

On Dec 12, 2009 I used anything I could find laying around in the basement and garage to mount all of the parts to plywood. I mounted the transformers, the power switch, the keyboard interface PCB, and the keyboard.

Clear Screen Button

On Dec 11, 2009 - I added a momentary switch for Clear Screen, per the schematics.
The switch uses +5v which is supplied by the ZIFF on the "CPU" side of the small PCB.
I also worked on mounting the keyboard and motherboard to plywood.

Keyboard connected, up and running!

On Dec 8 at 1:15AM I finally had reset working and dropping into the monitor program. After building the keyboard circuit, I keyed in the test program from the Apple 1 manual. Eureka! Well, one board works (the one that came with the kit). The board I built from scratch components doesn't pick up keyboard events yet, so this board will need additional debugging. But as you can see on the board that works, the ASCII charset is being dumped repeatedly just like it is supposed to.

I started the night with building the Apple II keyboard -> Apple 1 mapping circuit based on WSander's mapping schematic. I did not wire up the Repeat -> Clear mapping yet (which requires one trace modification on the keyboard).
Pin 1 (+5v) on the Apple II keyboard ribbon cable was broken clean off, so I had to separate the wire from the ribbon. I did this with an Exacto blade. Then I extended it about 5 cm by soldering another piece of wire. I didn't have any heat-shrink on hand, so I had to use electrical tape to cover up the bare connections. This made the wire long enough to sneak it underneath and into the DIP socket. As you can see in the photos, I used 16 pin ZIFF sockets on each of the ribbon cables. I also added a DIP socket to each end of the ribbon cable to protect the pins.

One thing worth mentioning, as I am not that familiar with Apple II keyboards -- there is a switch on this particular 1979 model, underneath the keyboard on the encoder PCB. This switch has 2 settings: Ctrl and Reset. My keyboard Reset button did not work until I flipped the switch from Ctrl to Reset.

Apple II Keyboard to Apple 1 mapping/schematics

All of the preceeding images were sent to me by W.Sander
I will be using Sander's design for my keyboard rig. He was kind enough to go out of his way to obtain the video signal images and a nice image of the Apple 1 screen when the system is first booted.
Note that the ampersand symbols flash, but the dashes do not flash. Check out the cool case for the Apple 1, also designed by Sander.

Clock Signal on Clone number 2

This is a shot of the clock signal on the 6502 / PIN-37
The peak is at 4 volts, and the frequency is 1.020 MHz. Horiz sweep is 500.0 ns.
I'm not sure why there is a negative spike in each cycle?
You can see the same spike in one of the photos below, on the analog scope taken from Clone number 1.

First Glimpse of Working Video on Clone number 2

This image shows the first time I had ever seen video. I don't know why one of the chars is blank, but that only happened the first time I powered up the board.