Archive for September, 2009

Apple 1 Replica Project Restarted #2

Tuesday, September 29th, 2009

This board is proving to be tougher in some respects than the Apple II. I’m glad I did the II, first. The Apple 1 has slightly smaller traces that are closer together than the II. Bus layout is also more difficult to replicate as the II had most of the busses running under the rows of RAM/ROM and Slots, which made for fairly easy alignment between the rows of pins.

The board is also slightly larger than a II, with a gold finger connecter (more $$). With the rarity of parts, plus power supply circuitry, I wouldn’t be surprised if this going to cost as much or more to put together than the II.

Also I plan on building a batch of the PS2 to ASCII keyboard http://www.willegal.net/appleii/appleii-kb-int.htm interfaces to go with this project. This will provide an easy way to download software, such as Basic from a PC into the machine without having to deal with a cassette port.

One other point for those that have seen the Obtronix replica. That was a very well done project. However, I’m expecting that my Apple 1 PCB will have even more accurate routing of traces, as well as a more accurate silkscreen. Check out my rev 0 replica to actual comparison page http://www.willegal.net/appleii/appleii-compare.htm to see what I expect to do for the Apple 1.

I estimate that this project will take 4-6 months, possibly longer to put together, so if you want a nice project to fill in some of the time, while you wait, Apple II rev 0’s kits are available and ready to ship. ;)

I’m able to wire in two to three 16 pin chips a day. Attached is a snapshot showing current state of the project.

Regards,
Mike Willegal
Picture 3

Apple 1 Replica Project Restarted

Monday, September 21st, 2009

Using available off the web images, I had already done some preliminary work on the PCB layout. However this was put on hold, sometime back, due to lack of really good images of the original. It was too hard to work with the relatively low res images, that I had. Last week, an Apple 1 owner provided me with hi-res pictures of the front and back of an original Apple 1 motherboard.

For some bizarre reason, I derive a lot of satisfaction from the process of reproducing an original board. Now that I have an quality original image of both front and back, I can hardly stop myself from working on it. I will be able to leverage experience and CAD libraries from the Rev 0 project, so I’m hoping that this project moves along a little quicker than the rev 0 project, did. To make up for this, I do expect a lot of challenges obtaining some of the rare components needed to build an operating Apple 1.

I do hope I can come up with an image of an original board, without components mounted on it, which would remove the guesswork of routing traces hidden by components. However I’m not considering this a show-stopper.

Regards,
Mike Willegal

check out my City Point Railroad page

Tuesday, September 15th, 2009

Check out these web pages which contain some information on the City Point and Army railroad of 1864-1865.
http://www.willegal.net/railroad/citypoint/citypoint.htm

Dynamic Microphone Preamp investigations

Tuesday, September 15th, 2009

Check out this web page.
http://www.willegal.net/preamp/preamp.htm