Recent content by Porcupine

Ah, thanks! I learned something today. This will be a nice project to repair. :-)

I have two Minibee terminals. One is working fine, but the other has weird speckles on the inside of the tube. I turned up the brightness so that the speckles are visible in the photos below. The spots are black, and are behind the glass but a few millimeter in front of the phosphor layer. It...

I try to avoid multiple projects simultaneously, but it sometimes cannot be helped. One particular reason has not been mentioned yet. Sometimes I get stuck on an 'inexplainable' problem, some weird fault or behavior that I cannot seem to pinpoint and fix. It then often helps to set that issue...

Nice find! I also know of the computer museum of the University of Stuttgart in Germany. They have disk images, and a user manual (in German) at ftp://computermuseum.informatik.uni-stuttgart.de/twin/ . All these resources do help me in piecing information together. Will update my website. Thanks,

I only learned about the Tectronix 8002 today. Looking at the Millennium_internal_floppies you mentioned and extracting the files from those disk images I got the binary for TekDOS. Much to my surprise that code is for the 2650 microprocessor. Disassembly reveals several code-similarities with...

I have a Signetics TWIN (Testware Instrument). It is almost identical to the Millennium Universal One development system, which is again very similar to the Tektronix 8002 Microprocessor Lab. I am not sure who the original designer was. I do know that Signetics contracted Millennium to develop a...

Yes, I believe you are right. Funny that all CPUs marked CT429I also carry the 2650 label except mine. And the label is printed in 'landscape' orientation, not 'portrait' as usual. Mystery case solved.

I stumbled upon the following mystery 40-pin CPU. The marking says CT429I, manufactured by Signetics. However, I cannot find reference to this chip in any of the Signetics documentation. The I-suffix indicates ceramic packaging, so I'm really looking for references to the CT429 CPU. An...

The Signetics TWIN development system is a minicomputer containing at least two CPUs: a main processor (the Signetics 2650) and a secondary processor which can be another 2650 or any other contemporary 8-bit microprocessor. The operating system and debug hardware allow for interaction between...