ZX Spectrum Projects – Diagnostic & Repair

November 1, 2019

Now I’m back on my retro computers I’ve put together this quick guide for those looking to diagnose and repair ZX Spectrum computers.

Schematics and Service Manuals:

Having a set of schematics or even better a full service manual is the good thing to have before starting any repair. Fortunately for us, full schematics and service manuals for the all ZX Spectrum models are available on the web. I have my Speccy schematics printed out on the biggest paper size I’ve got access to, namely A3. The service manuals are a great place to start when looking to diagnose a fault.

Schematics and Service manuals can be found at:

World of Spectrum

Spectrum for Everyone

IC Data sheets

wikipedia
7400 series
4000 series
Zilog Z80

Diagnostic Software Tools:

Happily the ZX Spectrum has quite a few diagnostic software tools to help the would be fixer in his fault diagnostics. Most of these are based on external ROM device which avoids the need to have a fully working Speccy or the problem of loading diagnostic software from tape.

Here’s a few ROM based diagnostic tools

Brendan Alford on github has “ZX Diagnostic”

Paul Farrow of fruitcake has the following ROM tools: 128K RAM Tester & ROM Tester
he also has the official Sinclair Test ROM as well
Phil Ruston of Retroleum has the following “ZX Spectrum Diagnostic ROM”

Tools needed:

Hand tools
Side cutters
Pliers
Screw Drivers: Philips and flat blade
IC extraction tool

Soldering Iron
De-soldering tool

Multimeter

Advanced
Oscilloscope
Power Supply (Adjustable/current limited)

Diagnostic software tools (see above)

TV Monitor/Screen (or car reversing monitor for composite video)

Repair mat
Anti static wrist or foot strap
IPA Wipes (no not the beer) – Isopropyl alcohol to clean edge connectors and contacts

Good web sites:

If the your own best efforts have not yet found the problem then there several good web sites that share their repair achievements where you can search. I like the following sites:

Dave Currah of Tynemouth Software

nightfallcrew

If you’re still no wiser, then try asking on one of the various Retro Computing Forums or general electronic forums in their repair section if they have one.

Remember to share as much information about the Speccy model, what it is not doing and what you have tried so far. Avoid simple statements like “Speccy not working please help”. It goes without saying that following the forums etiquette for posting will usually get you a more productive and polite response.

World of Spectrum forums
https://www.worldofspectrum.org/forums/

These are more general forums:
atariage forums

EEV Blog fourms


10-years of blogging

March 26, 2019

Wow, it is 10-years to the day, on this day back on 26th March 2009 that I first wrote not only my first blog entry but also started my first blog here.

This blog started as way to share some of the projects I was working on and also some of the techie things that interested me.

Much has changed in these last 10-years. We’ve seen the rise of the maker community. The establishment of the maker ecosystem. The adoption of cheap development platforms such as the Raspberry Pi, Arduino, Beaglebone Black and many others as not only great educational devices but also serious tools.

So what have been the highlights?

Helping start Makerspace Northeast in Newcastle

Attending and meeting numerous makers at the various Maker Faires and maker events I visited and participated at.

Making many new friends through the maker communities.

Getting one of the very first Raspberry Pi’s back in April 2012 and then being persuaded to give one of the very first public talks about what a cool thing its was.

Spreading the maker idea and gospel via our own local eDay events.

I wonder where will the next 10-years take us?


No more Maker Faire UK

October 3, 2018

It was with great sadness that I read that Maker Faire UK will not be coming back next year.

The venue Centre for Life in Newcastle has hosted the maker event since 2009 and was the very first venue to host a Maker Faire outside of the United States.

I’ve been a regular visitor and exhibitor since 2010 and enjoyed every moment of my time at it.

Fortunately, there are still plenty of other Mini Maker Faire’s in the UK and I’ll hopefully be visiting some of them next year instead.

 

So a final thank you to Maker Faire UK, to the people who organised it, to the exhibitors who showed off many great projects and to the many visitors who came to see what it was all about.

 

Here’s the message from Maker Faire UK web site:

Important news

In 2009, Life Science Centre brought Maker Faire to the UK and has hosted the country’s flagship event ever since. Over that time, the popularity of making activities in the UK has sky-rocketed.

Life is proud to have been pioneers in this growing Maker movement, but we feel the time is right to make a change and to bid a fond farewell to Maker Faire UK. Lovers of all things making needn’t fear, as we’re opening a new space in Life Science Centre dedicated to crafting, tinkering and creativity in the spring of 2019.


Old tech books = fun

July 31, 2018

When design and building my recent RC2014 boards one of the things I’ve found most useful and fun to re-read them after so many years has been my collection of great old tech books and data books. You’ll probably recognise a few of them. Here’s a brief list in no particular order:

 

 

 


Maker Faire UK 2018

May 4, 2018

New Raspberry Pi Zero add-on boards for sale

March 15, 2016

Following our earlier announcement we’re added the following Raspberry Pi Zero add-on boards to our Tindie store.

RS232
RPi0_PIIO_RS23202

Available on Tindie here:
https://www.tindie.com/products/DTronixs/raspberry-pi-zero-piio-rs232/

Break0ut

RPi0_PIIO_Break0ut01_small

Available on Tindie here:
https://www.tindie.com/products/DTronixs/raspberry-pi-zero-piio-breakout-/


PropBerry – Propeller & Raspberry Pi combo

July 31, 2012

For PropBerry, I was thinking using a Parallax Propeller* (or just Prop) as a super i/o co-processor for the RPi where the Prop would be used to offload the real-time I/O and let the RPi handle the higher program features. After talking about this combo on the Parallax forums, the Props VGA video capabilities were mentioned which got me thinking about using the PropBerry as a VGA serial terminal console and shelve the i/o co-processor idea for now.

The Parallax community is great and they’ve released a lot of good stuff. One of the things I remember (from about 2009) was Vincent Briel’s PockeTerm terminal software for the Prop. Using this on a Propeller Demo Board gives us a VGA video output and PS/2 keyboard for user input. A serial interface connects the Propeller demo board to the Raspberry Pi.

Now we got our bits together lets see if we can make them work 🙂

* The Parallax P8X32A Propeller chip (or just Prop) is a cool chip. It is a multi-core architecture parallel microcontroller with eight 32-bit RISC CPU cores (cogs) which share a common hub of 32K-RAM