Robert Morrison

Upgrade time! I’ve added a combined 512K ROM / 512K RAM card to my RC2014 which replaces the two respective cards from my old setup and also brings the RomWBW system to explore. I’ve had the upgrade kit since the Retro Computer Festival in November and finally built it tonight! #Z80 #CPM

RC2014 Pro modular computer. The combined RAM and ROM card has been separated from the backplane. RC2014 powered-up with green LEDs glowing brightly.

I love an 80s computing book with completely unhinged technology metaphors.

Photograph of the from cover of “The Hacker’s Handbook” a ZX Spectrum 48K communications guide by Longman publishing. The illustration depicts orbital ZX Spectrums encircling the globe. A diagram from the book. The concept of duplex send and receive communication lines is, for (presumably) some reason, illustrated as two pairs of handlebars with the brake lines connected such that pulling the right hand brake lever raises a flag on the left hand lever of the other side. Biblically-accurate rendering of RS232 from the perspective of the computer. Allegedly. I quite like this one to be honest, I might get it as my next tattoo. We’re back to handlebars but this time with six brakes and umpteen flags. The brake lines are labelled TxD, RxD, CTS, RTS, DTR, DSR, circuit common, and DCD.

What ho, Saturday‽

A photograph of my desk with a book, a notepad, a pencil, a mug of tea and a calculator.

Happy upgrade day, gang! (I retired my clunky old bodge-wired external IDE interface in favour of a sleek internal fancy one). #ZXSpectrum #Plus3e

A ZX Spectrum +3e main board in a clear Perspex sandwich (in lieu of its original case). Inside can be seen all the gubbins including a new IDE interface with a bright red LED.

Fitting ZX-HD with a new Raspberry Pi Zero. It’s a socket connection which means that normally there’s no need for soldering, but this Pi Zero had no header pins so they needed to be fitted first.

Partially reassembled ZX-HD interface with back removed showing a Raspberry Pi Zero inside. Also pictured: soldering iron and various soldering gubbins.

Are any ae yous intae Spreadsheets? They’re sick, man. #productivity #hustle #workSmarterNotHarder

Photograph of the clamshell case, manual and 3" disk for Tasman Software’s “TASCALC” which is a spreadsheet application for ZX Spectrum. The styling is familiar among the Tasword family of software. The disk label for TASCALC is metallic gold/bronze colour.

Mmmm-rrrrrr Crrrrrrrzmrrrrrrzz, rrrrvrrrrr-rrrrrnn!

ZX Spectrum loading screen featuring a festive zombie

I’m about a week late but I’ve found something “healthier” and all together more fun than chocolates. #advent #zxspectrum

A wall-hanging advent calendar composed of several numbered canvas pockets that happen to be about the size of a standard boxed cassette tape. I’ve refilled the pockets with a selection of ZX Spectrum games including Moley Christmas, Mrs Mopp, Seymour goes to Hollywood, Codename Mat and Shinobi.

Gotta toast fast #zxspectrum

Disassembled ZX Spectrum+ 128. The iconic finned radiator heatsink has been detached, as has the voltage regulator. Also pictured is a syringe of thermal compound normally used on PC CPUs or GPUs or whatever.

Day #2 in Cambridge In the city centre on the Sinclair and Acorn trail.

The Corpus Clock. An enormous gold chronograph. It’s eh, quite striking. Horologically speaking. The former offices of Uncle Sir Clive at 6 Kings Parade The gleaming and modern official Rasperry Pi shop. I don’t really need another Raspberry Pi so I just came away with a branded mug and tote as a keepsake. The highly-recommended Jack’s Gelato was great and understandably busy.

Retro Computer Festival 2024 Centre for Computing History in Cambridge I had a lovely time and spoke with many lovely people! A very welcoming bunch of retro folks, with so many interesting stories to share. Thanks to the CCH for a great event!

Main exhibition space at the Centre for Computing History. The room is filled with tables laden with vintage computing equipment. ZX Spectrum prototype mainboard and keyboard on display at the museum. Several computing devices showing key-based entry systems from simple keypads and membrane keyboards to full travel keys. A display of Heathkit computers magazines and catalogs from the late 70s. The machines are operating, with their numerical displays glowing.

Fun with MIDI!

Short clip showing a RaspberryPi with a MIDI hat connected. The blueish white RX indicator is blinking furiously. (It’s playing GRABBAG.MID but you can’t hear it because this is a GIF).

The Micro Enquirer (Spectrum)

I am on my holidays.

Animated GIF. Image shows a wall mounted hotel room TV displaying the loading screen of Future Knight on ZX Spectrum (the computer is on the desk loading the game from cassette tape).

I’m working on my (second ever!) ROM hack this weekend and a random glitch has given me an idea…

A screenshot from Jetpac on the ZX Spectrum. The rocket ship graphics have corrupted and it has turned into an improbable tower of jumbled spaceship parts. Matchbox “Con-nect-ables” branded toy vehicles in a retail hang-card blister pack. The toys are segmented so you can recombine them in interesting ways such as adding wings to a car, and so on.

Work in progress! (This photo didn’t attach to the previous post for some reason). I’d had the thing open years ago to service the belt or something but the old brittle wires gave way and it took some effort to deduce what goes where! It languished in the garage for ages; being raided for parts a couple of times, but I decided to give it another go last night. I couldn’t find a schematic for the whole unit, but the data sheet for the LA4160 amplifier IC was very helpful.

Photograph of a disassembled shoebox style cassette recorder. There is a cassette in the exposed mechanism and many wires all over the place. I’ve connected a logic probe for some reason. It’s playing Matchbox Twenty but you can’t hear it because this is a photograph.

Fixed it! I had to improvise an output socket—I harvested the original one when I thought this player was beyond repair, but this was my childhood Spectrum cassette recorder so I made the effort to fix it. #HiFi #ZXSpectrum

Cassette recorder with an improvised earphone socket made from a small breadboard and some jumper wires. There’s a resistor for decoration but it’s not serving any electronic purpose. The breadboard has been optimistically labelled “HI-FI”. Overhead photo of the cassette recorder showing lots of patina from decades of wear and tear. It’s dusty, scratched and worn with a small faceplate around the tape counter missing. A red cassette tape can be seen through the deck window. The label reads: SKATE OR DIE; DOUBLE DECKER TAPES. A modified ZX Spectrum with a white key mat and a shiny RTS sticker (see RoseTintedSpectrum on YouTube dot com).

Midnight maths club

Tonight we’re learning (or really just enjoying looking-at) bifurcation diagrams generated by Feigenbaum constants (…and very slowly plotted on a ZX Spectrum!)

Photograph of a CRT telly displaying a Feigenbaum constant bifurcation diagram generated by a ZX Spectrum Photograph of a CRT telly showing a BASIC listing of the program that generated the diagram in the other picture. The program is by Ettrick Thomson.

I had a great time at the Acorn Computers User Group meet-up last night in Falkirk. I was notionally representing SAM Coupé, but I spent almost the entire time learning about Elks, Masters, and RISC OS machines (and much more!) More pics at Spectrum Computing forum.

📷 Tosk / Retro Rendezvous

SAM Coupé computer with a few expansion cards plugged in, connected to an LCD television. On the screen is a blue and green horizon. Disks (and a spare SAM Drive) are scattered around.

“The marvellous thing about a singing horse is not that it sings well but that it can sing at all. To accomplish speech synthesis on a Spectrum with no additional hardware is a marvel of a similar order”.

Spectrum Computing issue 01

Screenshot of a CRT television set. Text on screen reads: The marvellous thing about a singing horse is not that it sings well but that it can sing at all. To accomplish speech synthesis on a Spectrum with no additional hardware is a marvel of a similar order. Spectrum Computing title screen. May/June issue (c) 1983

ZX Spectrum PlusD (clone) disk interface. The last of the parts arrived today so I blew the EPROM and programmed the GALs. And it worked!

An almost fully populated PlusD interface circuit board with three ICs missing. Using a GUI on an ancient Windows laptop to operate a USB programmer (a cheap TL-866-II clone) to program a GAL. Picture shows the programmer device sitting on the open laptop with the GUI on screen. A slim 20 pin IC is inserted in the programmer, and the device has a brightly glowing red LED. PlusD interface connected to a 48K ZX Spectrum. Floppy disks, drives and ribbon cables are strewn around. Yellow and red LEDs are brightly glowing on the PlusD. It has no casing, so the circuit board is visible.

Tell you what, going back to 1206 SMT components after working with 0805 scale devices is like moving paving slabs around. (Strawberry Chuppa Chupp for scale)

Detail of a partially assembled circuit board. Small SMT components on millimetres in size have been soldered to the board. A strawberry Chuppa Chupp lolly has been put into the photograph to give a sense of scale.

Well. Time to learn how to blow a GAL. 👨🏻‍🏭

Two DIP IC chips in plastic storage tubes, and several transistors in a small plastic bag.

I thought something was wrong with my PlusD disk interface so I took it apart for inspection… and who would’ve guessed it, the problem was just a duff floppy disk! 😩🥴😛💾💾💾

PlusDLite disk interface without its casing, plugged into a ZX Spectrum +2A. A couple of disks are scattered around with labels “Zeus Assembler” and Beta DOS”.

It’s never given me any trouble to be honest, it’s easily one of my favourite Spectrum accessories.

(I’ve no idea why I didn’t immediately suspect the well-used second-hand disk I got in a job lot from eBay!)

I quite often replay the original Tomb Raider around Christmas time, but I really associate it with the new year. Anyway this year I was looking up some of the secrets I’ve never found, and discovered a bug(?) in the PAL version: the third secret in The Cistern is inaccessible!

Screenshot of PAL version of Tomb Raider, the Cistern level. Lara Croft is standing on a stone balcony looking at a disguised moveable block that’s hiding a secret area. The texture of the block is slightly different to the surrounding walls. Screenshot of NTSC version of Tomb Raider, the Cistern level. Lara Croft is standing on a stone balcony looking at a disguised moveable block that’s hiding a secret area. Unlike the PAL version the texture of the block is the same as the surrounding walls so it’s harder to find. (Note the screen borders as this is running on my 50Hz PAL Saturn!) Screenshot of NTSC version of Tomb Raider, the Cistern level. Lara Croft has moved the disguised moveable block revealing the secret area behind.