2. Finished projects


As a former employee of DEC ( Digital Equipment Corporation ) I dealt predominantly with the systems of the PDP-11 series. It suggested itself that I also cared about PDP 11 architecture at the restoration and preservation of my Computer Oldies because I still know this architecture very well. For more than 2 years I have dealt now with the restoration and recovery of these type of Computers, but it is more than 25 years between this. The tracks can not only be recognized by my Computers but manifest themselves also with me, because I am also already an Oldie in the IT industry and do not want to conceal this either. In my time at DEC I always wanted to realize a little specially, unique and built at that time in the leisure time my SINGLE BOARD COMPUTERS (SBC) and a PDP-11/23. These systems are up and running again and a detailed description is in the chapter 3 to 5. A good contact list and a good cooperation arose also with the Computermuseum München in Munich which I virtually in an honorary capacity work for now in my leisure time. Through this I got in addition a Micro-PDP-11 with attached RL02 disk drive into my collection and at that time, I was able to start the project like in the chapter 1 described. As of 2013, my PDP-11/23-SE also will find a space in the Computer-Museum in Munich if the development of the showrooms is completed. I am very proud of it. The work with the My Computer-Oldies makes me much fun expressed, symbolically with one hand within the years as of 1980 and with the other hand in the year 2010 because I work virtually as “time bridge“.

Restoration: The reparation and restoration of vintage computer systems often results in the practice as very problematic because there are no more spare parts available. Mostly, the only way to get this issue managed is reconstructing an up&running system of several faulty components. Another problem arrives: The older the devices, the more failures. Most problems are related to the old power supplies especially with all the old electrolyte capacitors (Elko), because they have often dried out after 20 years. The major problem with this components is, that it is a creeping process and can't recognized from the outside. If a catastrophic failure occurred triggered from a Elko, the aftereffect symtoms can be fatal what I experienced at the restoration of my PDP-11/23 by myself. Therefore, my solution trial is to replace the old power supplies by modern power supplies completely. Mostly, this still indicates additional overhead because most of the old computer systems only can start with a exactly defined sequence of the Power-Up signals. A more exact declaration is in chapter 5.
The restoration topic gets even more complicated within all the vintage disk drives and therefore I try to realize the project like described in chapter 1. Also in this case , my attempt is to use new technology to guarantee a permanent preservation of the old software.