Recent content by jdreesen

Here is the sourcecode for CTOS, the cassette operating system for the earlier versions of the DP2200 / DP1100. Later versions of the 2200/1100 ( and 5500) use a videocard with a programmable characterset, not supported by this early CTOS version. It was obtained by OCR'ing and handcorrecting...

>> Jos: So what happened to your PSU when it killed itself? Mains rectifier shorted, that also took out the main chopper transistor and the LM555. It took a while to find a suitable replacement for the chopper transistor ( a BU931 will work instead of the SVT6002)

That is the advantage of the newer type PSU in my machine : at least no live voltages go into the backplane.....Conceptually it is the same though. As said in my PM : take care with the L1 ( smaller metal box ) Its is mounted to the PCB with tiewraps that now are very brittle from aging. The...

As Mattis mentioned i have a DP1100 ( DP2200 minus cassettes) I also have the full set of cassettes for DOS.D 2.6 Still have not found a good way of reading these, and anyhow DOS.D is for a DP5500, not 2200. Individual programs from my floppies should run on a cassette, but I know of no means to...

We can talk about a new MFM version end of September, that is if AK's bears dont get me first !... Relying on a 4054 does limit the audience though...

I had not read the whole thread, sorry. But yes, you are right w.r.t. the images.

The DRP you'll receive is tested, so if it does not work at your end you'll have to debug the 4052 end. Important : which images exactly ? I posted 2 versions, the original ones ( can be found on bitsavers ) and a transposed one, intended for wsi57c49 EPROMS ( slightly dirrefent pinout) . You...

Well, since the discussion is public anyhow : I do indeed have a spare, but incomplete, 4052 keyboard. Keycaps differ between 4051 and 4052/54, as per Tom's pictures. And while rummaging through my parts boxes yesterday I found around 25 (used) switches, without keycaps, that are a perfect...

The Datapoint 9350 is also a Diablo-30 series disk, with 24 sectors. I have the controller & drive, but no documentation beyond the command description, as found in Bitsavers.

Brain fart....that was of course the assembler that I posted, not the disassembler.... Like you i used a 6800 disassembler ( fd9dasm in 6800 mode ) andf handcorrected the endresult. Which I then assembled again to do a binary compare with the original binary. Sorry for the misinformation !

It is...

If you need to disassemble lots of 4052 code, then you could use my adaption of Bruce Tomlins universal disassembler. This includes all new 4052 opcodes. The zip-file (not .TXT !) is included below. I used to to disassmble the Transera 764 RAM code, since that neede chanes for my auxMEM project.

The first batch of DS12885 I received were fakes. Maybe I've let one of those slip through. I'll send you another one.

Not my auction, but these things are rare enough to mention them here : https://www.2dehands.be/v/computers-en-software/vintage-computers/m1991240973-plato-iv-computer

Which RTC chip did you use ? "Please contact the local Tektronix service center" In 2023, that would be Monty ! Jos