Mike's Hobby Blog

Pre-order your ACI  now – in case you forgot to order by end of September, the special price of $75 will be honored through Sunday 10/3/2010.

I have already ordered the PCBs and will get a first look at them next week.  Still have to order a number of parts and will be doing that by early next week.  By the way, I’m looking at buying carbon composition resistors which are more representative of the resistors used on the original units.  Only downside is that they are 10 times the cost of carbon film resistors.  If they work out, I’ll also switch Mimeo 1 kits to these resistors when I run out of the current carbon film resistor stock.

I recently received this question from a fellow retro-computer hobbyist.  Since it was such a good question, I figured I’d post my reply here on this blog.  Though I can’t make a specific recommendation that is right for everyone,  here is how I responded to this inquiry.

I use an old 100MHZ Tek 465 that I picked up off of ebay for about $80 (shipped). I was  lucky, and it was almost completely functional, when it arrived. I spent another 50 bucks on probes and some minor repairs (replacing broken knobs). Total cost was less than $130.

Prior to landing this unit, I would occasionally borrow a more modern HP 20MHZ 4 channel digital storage scope from work. The user interface was nice and storage was great to have, but the bandwidth was a bit limited, considering early Apple computers have a base  14MHZ clock.

At times, it wouldn’t hurt to have more than 2 channels and occasionally a little more bandwidth would help. So I guess I think that 100 MHZ, 2 channels is minimum for my  purposes. 100MHZ sounds fast, but remember that you want to see glitches and signal  slope, not just digital highs and lows. The real neat thing about using this old scope is that this same tool was in use in the 70’s and 80’s by developers of the first personal computers. The price was right, too. At the time I bought it, I don’t think that you could touch the bandwidth at that price any other way.

A modern digital storage scope would be easier to use, especially on transient signals, as the scope stores the capture and you can view it at your leisure. On a traditional analog scope, a transient just flashes on the screen and is only present as long as the screen phosphor glows (one shot).

There are also digital storage scopes that plug into PC’s USB port and use the PC as the  brains and display. Some of them have logic analyzer functions, which would be nice to have. Many of these units have limited bandwidth, compared to my old 100MHZ Tek.

I guess the bottom line is you need to decide much you want to spend and what kind of features are  important to you.

My presale of apple cassette interface cards is due to end on 9/30/2010.  The presale price is $75.  After 9/30 the price will go up to $100, unless you buy an ACI at the same time as an Apple 1.  The bundle price will be $75.

I expect the ACIs will be shipping by early November.

I currently have a preliminary manual online at:

http://www.willegal.net/appleii/aci-v0.12.pdf

and some information about the  ACI at

http://www.willegal.net/appleii/aci.htm

I’ve put a preliminary copy of my ACI build and operations manual online at: http://www.willegal.net/appleii/aci-v0.12.pdf This contains an OCR’d copy (not just a scan) of the original Apple ACI manual, plus a complete assembled listing of the ACI PROM. Take a look and let me know if you see any problems.

Also – remember that this is the last month for discounted ACI presales – get the presale price of $75 through September ’10. Shipments begin late October or early November. Contact me via email at mike@willegal.net if you are interested in the ACI card.

Hi,

I have just posted my latest hack. This is a small C program that will convert an Apple Command Line file to AIF format. This AIF format file can easily moved to an iPod and be used to load your Apple 1 through the Apple Cassette Interface.

The program and more information can be found here: http://www.willegal.net/appleii/apple1-software.htm

In case you are wondering, an example Apple command line format file might look like this:

0: A9 00 AA 20 EF FF E8 8A
: 4C 02 00

I just posted pictures of my new PEM (power entry module) on my website.

http://www.willegal.net/appleii/apple1-enclosure.htm

In my opinion, it looks about 100 times better than the crude wood box I was using before. Plus it is smaller and lighter. Judge for yourself.

new power entry module

old power entry module

The Panasonic RQ2102 cassette recorder works about 100 times better than the period Radio Shack recorder that I was attempting to use. I recommend that all Apple 1 owners get one of these while they are still available.  Since it works pretty well, I’m go to go ahead and start the process for making a batch of ACI kits.

First,  I’ll take names for the wait list. Though the layout is done, I don’t want to invest the money until I build up a wait list of around 15 units. Send me an email (my address can found on my website) and I’ll put you on the wait list.  Once the wait list reaches 15 or so units, I’ll ask for money and then order boards and parts.  I expect the cost of the kits to be under $100.

I’ll publicly track the wait list with your initials, date I received your request, and number of kits desired on my ACI page.