Restoring a ZX Spectrum+ Toastrack

I talk a lot about Commodore machines in this blog; they left a bigger dent in me growing up, but like most kids of my generation living in Portugal in the 80s, the first computers I played with were actually Sinclairs—first my friend’s ZX81 and then a ZX Spectrum 48K that my parents offered me. I have many memories of playing games like the Horace series, Manic Miner, Jetpac, or Chuckie Egg on my Spectrum.

I’ve been keeping a few Timexes and Spectrums that have been offered by friends who know about my retro-computing addiction and that I’ve collected over the years, stored away waiting for an opportunity to bring them back to life.

This is not the first time I’ve fiddled with Spectrums during the last few years. In 2019 I wrote a ZX Spectrum game for one of the Pixels Camp events and blogged about it. More recently though, I’ve been restoring and improving a rare ZX Spectrum 128k+ “Toastrack”. This is how it’s going.

Initial assessment

This Toastrack is not in bad shape if you consider that in general all Sinclair models are quite fragile, made to be cheap, and the materials aren’t of great quality. The case is in relatively good condition, it powers up and boots (most of the time), and the keyboard kind of works (the membrane is dying).

The first thing I did was a visual inspection and some basic checks. I looked for bad PCB traces, corrosion, leaking capacitors, cold solder joints, things that didn’t look right. The good news is that I found none.

One thing I noticed was that once I powered it up, it wouldn’t always boot, but pressing on the integrated circuits on the PCB sometimes helped. This is common. I reflowed the big chips like the ULA with fresh solder, sprayed the IC sockets with a contact cleaner, and put the chips back in. Pretty basic stuff to do on a computer that hasn’t been turned on for decades. It helped.

I then grabbed the electronic schematics; RetroSix Wiki has them all, and got on with other upgrades.

7805 regulator

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