In the previous post, I had repaired a CBM 4016 board. I had reached the stage where it was working with a PET ROM RAM board to replace the ROMs and known working 65xx chips. The video RAM was also replaced with a 2114 video RAM replacement board. At that point, I would normally leave it. The...

   A while ago I was donated a CBM 4016 board from a non-running PET. The board was no longer required, as the owner had bought a Mini PET 40 80 board to replace it, and I was very happy to offer it a new home. It looks in reasonable condition, I think the story was the PET was bought as not working,...

   Introducing the new Minstrel ROM Cart. It plugs into the Minstrel Expansion Bus slot on later Minstrel 2 and Minstrel 3 board. Or a Minstrel Expansion Bus backplane on a Minstrel 2, 3, ZX81 or TS1000. (but not a ZX80, as that is missing ROM CS, but you’re not planning to plug this into a ZX80 are...

   This question comes up a lot, so I thought I would compile all the various versions into a single post I can point people at. Background All Commodore IEC and IEEE-488 devices need a unique ID to talk to the computer. Most disk drives default to device ID #8, but it is common to have secondary...

   Put your Flip Flops on, let’s go for a deep dive. The 74HC74 (or 74LS74 or 74HCT 74 etc.) is a commonly used part in my designs and many others. I thought it would be interesting to have a bit of a run through some of the many and varied uses of such a useful chip. It is a dual D-Type Flip Flop....

   When I relaunched the Minstrel 4th earlier this year, I added some more ROMs to the standard ROM image. These included the ZX80 and ZX81 BASIC I have talked much about, and the Enhanced Forth ROM which I have not. This is the work of Alexander Sharikhin, and features additional code by George...

   This is a problem we see every now and then. Someone buys an SD2PET, plugs it into their PET and tries it and they get the dreaded ?Device Not Preset Error. (I should apologise now as all the screen photos in this post are going to be rubbish as they are taken from an 8032 CRT and I am clearly...

   I first used microcontrollers in the early 1990s, with I think the PIC16C54, a homemade parallel port programmer and one of the versions of this book constantly on my desk. Looking at the features of that now it rather surprisingly minimal. It has one 8 bit timer. 512 bytes of code and 25 bytes of...

   I sometimes wonder what exactly the manufacturers of logic analysers and the like think that people user them for. I have seen several come with leads like this with quite large clips on. Or worse, this set with all black wires and even larger clips. Side note, back in the 80s I knew someone who...

   New from The Future Was 8 bit - A combined SD2IEC and Fastload cartridge, in a special limited edition collector’s edition founders edition known as the Pink Windmill Edition . This plugs into the cartridge port on your Commodore 64 and a lead plugs into the IEC socket on the C64 and you’re done....

   Over on my Patreon Discord, we have been looking at several versions of Forth for the ZX81, including Husband Forth and Tree Forth. Those (just about) work on the ZX81, but none of them work on the Minstrel 3. George Beckett is currently reverse engineering those to see how they work, and we think...

   There are lots of things in the VIC20 Penultimate Cartridge. The current release, the 3 DCR has 271 things. Total items (271) Games (233) Utilities (11) Development (8) Adventure Games (8) Board Games (5) Paddle Games (6) That lot should keep you entertained for a while.For example, if you were to...

   The PET ROM RAM board can replace almost all of the ROM and RAM in a Commodore PET. However, it cannot replace the video RAM and the character ROM, as those are integrated into the video circuitry. To replace bad ones of those in the PET 2001, I designed PET video RAM (6550 and 2114) replacements,...

   I started writing a blog post about all the Minstrel 4th alternate ROMs. As part of that, I wanted to include some extra ones, such as the faster than a ZX81 version etc. Whilst doing that, it seemed appropriate to revisit that and see if I could make that version any faster, and so I started...

   When I am testing a Minstrel 2 or 3, or the new Minstrel 4th ZX80 and ZX81 modes, I try to load from various sources. Sometimes ZXpand, sometimes a tzxduino based player, sometimes tape, sometimes vintage tapes. When testing the Minstrel 4th ZX81 mode, I tried various of my original 1980s tapes as...

   Seems like I have done a lot of these, but not for a while, so here are three more. We were almost at the release state for the Penultimate 3 DCR when TFW8b suggested a few more games to add following one of his 5 random games videos (link at the end). Out of the ones suggested, three of them...

   Available now from TFW8b.com is the new VIC20 Penultimate 3 DCR Cartridge. Just in case anyone doesn’t know what it is, here is a quick overview. RAM expansion, Menu selectable 0-35K, in 8 banks, giving a total of 280K ROM expansion, 271 assorted programs and utilities, ancient and modern including...

   Shipping this week from TFW8b there is an updated version of the VIC20 Penultimate Cartridge, the Penultimate Plus 3 DCR. Like the original Plus 3, this has a built in SD2IEC. This time it uses a full size SD card, and has the drive LEDs visible through the top of the case. There is also a...

   This is one of several attempts at writing the ZX81 BASIC on the Minstrel 4th blog post. It went on too long and into too much detail. I decided to start again and wrote a new version, the one you hopefully saw a few weeks ago. I decided to finish it off and add the missing pictures and even some...

   I like things nice and bright when I am working. I have a three way light fitting in the workshop ceiling, and had been using standard candle bulbs. I was looking around in .....checks jungle website history..... 2021 and found these listed as LED Corn Bulbs 26W 200W Equivalent . They looked like...

   When I started working on ZX81 BASIC for the Minstrel 4th, I had a fairly clear idea of what I wanted to get working, and also what I did not expect to work. As is often the case, my target was to get 3D Monster Maze working. I knew that would require slow mode, and that was going to be a challenge...

   TL;DR USB Keyboard Controllers are back. Get them here: https: www.tindie.com products tynemouth usb-keyboard-controller-for-vintage-computers History Today Way back in 2012, when the world made a lot more sense that in does today, this blog was mostly about software and web development, PC repairs...

   Last year, I uncovered a forgotten set of prototype Mini PET 40 80 PCBs and built one up. I posted about that at the time and a few months later, someone contacted me about buying a Mini PET, so I sold that. A few months after that, someone else asked for one, so I built another. Recently I had...

   I have written this post several times, one got to over 4000 words and I wasn’t even half way through, but they have all been a bit too rambling and probably going into more detail than anyone needs. So, this is the forth attempt (how appropriate). This time with more pictures and diagrams and ...

   I have covered this sort of thing before, but I thought it was a good time to revisit the process of building one of my Minstrel kits, and some of the steps you should take to troubleshoot any issues you might have. This is based on my experiences and my preferences. Yours may vary. Feel free to...