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Hi everyone, I was going over my 5160 to make sure there aren't any leaky components (there's a SixPakPlus card so I removed the battery). However I noticed that some of the cards wobble a bit much. Some cards have a black plastic bracket at the front end of the machine which prevents...

Hi, I have a 386 desktop machine from around 1991 that currently works (as of last year). The machine was custom assembled by my dad around that time and was used as the family computer long enough to end up with Windows 95 and an ethernet NIC. I would like to make sure it keeps working for the...

Hi folks, I recently obtained three Z-171 portable computers. None of them currently work and I'm planning to repair two of them. However the third one has been badly damaged. Looks like it was dropped at some point with a shattered screen and several cracks in the case. I've saved all the...

Hi folks, I'm working on my Apple II emulator and writing my own monitor ROM from scratch. I have some doubts about how key repeat was done on a real Apple II. Did the hardware prevent too-fast repeats (and take care of debouncing) or was this something that the ROM had to take care of (for...

Hi folks, sorry for the long post but I've got a point to make with examples. I've bolded the specific examples to help you pick through it. I'm thinking about long term preservation of computer history. Old hardware won't be around forever, and emulation will become an increasingly important...

Hi everybody, There's a DEC PDT-11/150 a few hours away from me. Good condition, probably works, but there's no boot media. It takes the 8" floppies. It seems uncommon and I'd like to add it to my collection for posterity. The thing is, it's hard to justify it if I can't make it do anything...

Hi everyone, I'm working on my Apple 2 emulator again. Trying to rewrite it to render the display through opengl instead of the hacky (text mode only) ncurses I was using up to now. I've been trying to figure out what the format of the character roms is. For example I downloaded the 341-0036...

In 1952, UNIVAC famously predicted the outcome of the presidential election based on a partial vote tally. I am trying to figure out exactly what algorithm was used. I know that the algorithm produced an overall prediction of the electoral college votes as well as a value ((percentage?)...

Hi, I was just looking through some the "archived" items in my collection to see what projects I might dig up. I have three "Superflow" boards from an old Kevex-branded (x-ray?) controller. I found my PDP-11/73 in the same cabinet actually, see my post from 2015. These seem to be part of a DAQ...

Hi again everyone, My Apple 2 emulator is working reasonably well now for the basic (heh) functionality and I am starting to to think of adding some more advanced features, In particular, I would very much like to add support for saving to "cassette" (or in this case, probably .WAV files or a...

Hi fellow vintage Apple enthusiasts, I wrote a 6502 emulator from scratch so that it can appear in a coding game I am writing (well also for the challenge). To test it I am emulating the text mode I/O of the Apple 2 and using an Apple 2 ROM. I am able to run the original Integer basic ROM. The...

I've just purchased a TRS-80 Model 100, a machine that I've been curious about for several years. It will hopefully arrive in a week or so! I'm aware that this machine has a significant fanbase still, and that modern accessories have been made for it. Just wondering if anyone can point me in...

Hi all, I've temporarily suspended work on my physical 11/73 due to insufficient electronic components lying about at the moment. Instead, I decided to try to get 2.11 BSD running in SIMH since that's what I indend to run on my 11/73 anyway. Everything has mostly gone well, except for setting...

I'm a CS grad student at an engineering university and there's a recycling area for old electronics on campus that I check frequently. I'm into all sorts of old computers and I have a meagre collection of mostly Apple 2 stuff, but I've always been most interested in the minicomputer era, and DEC...