Hello all, So I have recapped a few power supplies for older 32 bit Suns (ex: IPX, SS20) with success. No odd behavior, machine works as expected. However the SS10 PSU (Sony APS-39, SUN 300-1081/300-1255) is giving me fits. I have 3 total of these, and out of them only 1 seems to result in a stable machine. The behavior is quite strange - the machine panics right at soft shutdown/powerdown. After troubleshooting nearly everything else in one of my systems, I finally figured out that the problem follows the other 2 PSUs and there is 1 “good one”. All 3 PSUs “work” in the sense of the machine po ..read more

I have this great design for 18 bit cpu, that I plan to emulate. The concept here is one extra address bits,is used for byte addressing, and the other address bit for longer opcodes and floating point. Later I want to build it, but all alu’s are 4 bits wide. Can a 18 bit serial cpu work for me? I need 8 registers, Mar and Mdr, but no MQ. 18 bit addressing,9 bit bytes. 2 posts - 2 participants Read full topic ..read more

Hello, A couple of months ago I bought a BBC Model B for reasons of nostalgia. It works fine and loads programs from the ROM as well as a couple of things on tape. This week, I bought a Cumana 5 1/4 disk drive and around 100 disks on eBay (from separate places). The drive appears to work fine and searches when prompted, I am also able to enter the *CAT command and list the contents of every single disk. Unfortunately, whilst I can see what is on all the disks (leading me to think that the disk drive must be working) none of the programs load. I keep being given error messages such as “Bad Prog ..read more

This Poking Technologies channel looks and sounds familiar… it’s changed its name. But still good: Porting CP/M to a Brother SuperPowerNote Z80 laptop thing Here’s the top level menu for this late-1990s-era Z180 based word processor, before it was transmogrified into a CP/M machine: The path taken here, after a quick tour of the intended functions, is to do a bit of reverse engineering and modifying of a small standalone game that’s on disk (a Reversi/Othello game), mutating it into a simple monitor program, then using a logic probe with the monitor to find the I/O space for the floppy contro ..read more

From his blog: I’m in the process of retiring, and although I will not be settling back in my rocking chair—I have lots of writing I want to do—I’m no longer teaching. On April 30, I gave a farewell talk. If you’re interested, the video is here and the slides are here. (And you can always find both on my “Talks” web page.) Much of interest in the talk relating to computer history. Here’s a map of Usenet: Several anecdotes and recollections on his student days including some pranks (or hacks). I was an undergrad at Columbia College at a time when there was no CS major • I made up my own maj ..read more

Back over, at http://retrocomputing.stackexchange.com, there was a post asking for help in identifying a computer from an image (deleted, since). This is the image in question: While rather convincing at first glance, it’s obviously an A.I. generated image. Here, I’ve marked a few areas, where things either don’t make sense or are off (like “mutilated” keys, suitable for AI fingers only, or perspective): There may be also some aesthetic hints, like that monitor glow being just a bit too nice. However, this made me think: in a year or two, there won’t be such dead giveaways that an image was ..read more

Hello, Was the TCU-150 used often? What OS supported it? And on what memory-mapped address was it used most often? 1 post - 1 participant Read full topic ..read more

I’d like to invest in a Windows 95 setup where I can enjoy a '90s computing environment, browse the Oldnet, and write some C on Turbo C in the MS-DOS prompt. Does anyone have suggestions on where to get started looking for such a machine? I’d like to have: An old CRT display An SD card HDD substitute already in there A cleanish tower that boots into Windows 95 A keyboard and mouse in good condition Not sure if it helps (or hurts) that I’m in the Bay Area and there may be a large number of enthusiasts nearby. So far, I’ve only found some $300+ machines that are not even in great shape and do ..read more

This is an early 1970s clone of a PDP-8/S, but reduced to 8-bits. It was published in “Electronics Australia” magazine. There is a FB Group - and a modern set of repro-pcbs just arrived this week. Links to FB: Facebook Log in to Facebook Log in to Facebook to start sharing and connecting with your friends, family and people you know. 1 post - 1 participant Read full topic ..read more

I found this and first thought of a joke. But it seems to be real. But extremely rare. Never heard of it before. VIC 20 - Italia Commodore VIC 20 SMPL SYSTEM – VIC 20 Sincronizzatore di registrazione audio VIC 20 SMPL molto raro in quanto non si tratta di una macchina uscita così da casa Commodore ma un adattamento per gli usi descritti. Il ... Rare Commodore Systems Found at Electronics Recycler 2 posts - 2 participants Read full topic ..read more