created 14.11.2008, last changes: 04.03.2010 ps

# >>> Patrick's Hardware Page <<<

Here are a few odds and ends I created during the last years. They make more or less sense, and you may find them useful or just funny. Or not at all.

I am working as a Senior Hardware Design Engineer at an automotive electronics supplier. Here I spend some time designing circuits, and most of my time making them as reliable, cost efficient and easy to manufacture as possible. Therefore sometimes it is really necessary to build something that is quite useless, but in a certain way interesting, funny or just recreative. I like vacuum tubes, I like vintage computers, and I also like robotics. And because I have some other hobbies as well (and a girlfriend who does not share this attitude), I always have more ideas than time to carry them out...

From time to time I will add some more stuff here, but do not expect too much.

## Vintage Apple Computers

In 1984, I came across an Apple IIe computer. It was at a trade fair in our local town hall, I was thirteen years old, and I never had seen such a thing before. After that I wanted to have one.

At that time I was not able to afford a genuine Apple (not to mention any genuine software), so one year later I got a "MEWA-48" for DM 999,- from Völkner Electronic. A real Apple II (or IIe) was 2-3 times more expensive, so almost every "Apple II" user had a Taiwanese clone. You could buy them at almost any electronic store and they came in two basic designs:

- The GTAC-1 (generic taiwanese Apple clone type 1) design looks like the Apple II Rev 7 board, but with a different power connector and 2716 EPROMs. It has 48k memory, eight slots, 60Hz timing and a lowercase character generator.
- The GTAC-2 design has 64kB in eight 4164 chips. This frees some space on the board for a built-in CP/M softcard. Slot 4 is missing, also slot 0 (the upper 16k are used as a Language card). However, there is a special slot at the slot 0 position that holds a small PCB with two EPROMs for the firmware.

Taiwanese Apple clones were sold under different names, like "Orange II", "Telstar", "48k-Computer" or whatever. They had Applesoft BASIC inside, which was not really illegal these days because the copyright laws did not fully cover computer software. Usually the greeting string was patched to something like "HELLO" or "COMPUTER" instead of "APPLE ][", which prevented ProDOS from booting. And helped selling EPROM burners.

Many years later I bought a genuine Apple IIe at a surplus sale at our university. It was the machine Prof. Niemeyer used to work on the Hare-Niemeyer-Verfahren, a procedure to allocate the chairs of the German parliament to the political parties. This evolved into a big Apple collection. Today I own a many Apple IIplus, IIe, IIGS, an Apple ///, four Lisa 2, a Mac 128, Plus, SE, SE/30, Classic II and a Portable. And of course my old Apple clone.

Here are some documents and projects related to these great machines:

- Magic Skull, Meta Pin, Hurricane, Graveyard. Here is a disk image, 1005501A.DSK, with four pinball games Thomas Jansen and I designed in Summer 1987 using Bill Budge's famous Pinball Construction Set.

- And here is a disk image, 1004302B.DSK, with some puzzles for Broederbund Software's Lode Runner. Thomas and I created them around 1986 and they are really difficult, but it is possible to solve them. That time we were able to ;-) . I do not provide the game itself here because I do not know if I am allowed to. It may still be copyright-protected.

- IDEfile. A ProFile / Widget emulator that allows you to connect an IDE drive or CF card to your Apple II, /// or Lisa. I do not sell these devices, but you are invited to build your own. Before asking me any questions, please read the FAQ carefully. With any questions left, don't hesitate to ask.

- Eager to learn how the stuff works I did some reverse engineering to my computer equipment. As a result from this, here are a few schematics.

- Lisa Keyboard Tester. This is a handheld unit that allows you to test a Lisa keyboard without having to use the precious computer. Lisa KBD scancodes are converted into RS-232, and as a gimmick it works the other way, too.

- ...

## Hobby Electronic stuff

- Sascha Ittner inspired me to design my own ScopeClock. My design is similar to his, therefore I do not describe it in detail here. It is operated by a pre-production Atmel AT89LP4052 running at 20 MHz and uses a Valvo DG7-32 tube. I used Sascha's fonts and a big part of his code, but had to make several modifications and tweaks to match it to my hardware.

- The PWR/ADA-IO is a module for the c't-Lab test and measurement system. I created it together with Stefan Diestler, who had the idea of combining an IFP, an ADA-C, and an IO8-32 into one module and did most of the PCB artwork. Here are schematics, user manual, gerber files, and a front panel design.

- 486 Teapot Warmer: when the first processors came up that required cooling, I built a hotplate from four 80386DX-25 CPUs. These were supplied with 5V, overclocked at 33MHz and wired in a way that the execute "XOR AX, AX" or something similar I do not remember today. Since then this thing keeps my coffee mug on temperature in my office.

  A few years later, after the first i486 appeared in the scrap container, I decided to build the "MK II" version. Four i486SX-20 generate enough heat to keep a teapot on temperature. Again the CPUs were overclocked by 30% and they were in a way that they execute something useless. That was necessary because otherwise they go into some kind of idle mode (though SpeedStep was not invented yet) and you don't get the maximum power consumption. Power comes from a 6V "wall wart".

  Hotplate made of four i486 CPUs. Surely Intel did not specify that mode of operation, but it works fine. In everyday use since December 2003!

  Of course its obvious to build the next one from four Intel Pentium processors. It would definitly beat the candle-operated units. Unfortunately there are many pins to connect, with a 1.27 mm pin spacing that does not match the regular Vero boards. A Pentium 166 consumes up to 4.5 A at 3.3 V, so it all boils down to a (four-layer!) PCB. And up to now I did not feel like designing that. If you do, please let me know.

- ...

## Disclaimer & Copyright

This web page has been created by

> Dr. Patrick Schäfer
> Drei Schepps 26
> D-44227 Dortmund
> Germany
> dr.p.schaefer@gmx.de

As I cannot take any responsibility for anything outside my reach, I explicitly disassociate myself from the contents of any page linked here.

This page is hosted at John, a server of the Computer Club der RWTH Aachen e.V.