There are several types of Sinclair ZX Spectrum. So it follows that there are several different types of power supplies for the Sinclair ZX Spectrum.
This ranges from the rubber key 16k and 48k models, then Plus and 128 models during the Sinclair ownership of the Spectrum brand, through the Amstrad ownership of the Spectrum brand (after Alan Sugar’s Amstrad bought the rights to the Sinclair Computer brand), to the present with the new Spectrum Next.
This article (Part 2) talks about the only 128k Spectrum of the Sinclair era – the Sinclair ZX Spectrum 128 (a.k.a. “Toastrack”).
The Toastrack computer looks very similar to the Spectrum Plus, but has a huge black heat sink on the right-hand-side of the case. Hence the name, the “Toastie” or “Toastrack”. Inside, it is quite different, as well as the obvious extra RAM.
The power supply (PSU) shown in the photo above is a UK1400 model, which is OK for use on 16k and 48k rubber key models. The one below is the Spectrum Plus version of the UK1400.
Like the computer itself, there is a similar look of the Plus PSU and Toastrack PSU.
None of the UK1400 power supplies are suitable for any other model of Spectrum – not the 128 “Toastrack” and not the (Amstrad-era) Spectrum +2 Grey.
This is despite the fact that the DC (computer side) barrel connector will fit on these later models of Spectrum. And despite the fact that the Spectrum Plus UK1400 looks very similar to the Toastrack PSU.
Why? Because the power requirements of the Toastrack and Grey (subject of a future article) are higher than the 16/48 and Plus. They require more current than the UK1400 can deliver.
The UK1400 model is called the UK1400 because it delivers a maximum of 1,400 mA (milli-Amps). Or put another way, 1.4A (1.4 Amps).
The Toastrack needs more than 1.4A.
The Toastrack power supply can deliver more current. It can give 1.85A. This is why it is called the UK1850. Here is a photo:
You can see in the photo above that the case has the textured right-hand-side, which is different to the Spectrum Plus UK1400 PSU.
On the underside of the PSU, you can see in the photo above that the model number is UK1850 and the maximum current is 1.85A. The quality of work inside seems to be higher than in some of the UK1400 models.
The official Toastrack power supply is becoming hard to find now, especially in a decent condition. This is the only one that I have, at the time of writing. So I have not been able to do a comparison of the internals, like I did in Part 1 with the UK1400 model.
This Toastrack PSU needs some work to clean it up and to replace the mains cable, but it has been tested including an electrical safety (PAT) test and it is working. The PAT test failed due to a nick in the mains cable insulation, so it would not be for sale in the PopeyMon eBay shop until that was fixed. But it’s the only I have, at the time of writing!
If you are looking to buy any Sinclair power supply or want one checked, please get in touch.
I will happily sell you one – fully tested and working – for the Spectrum 16/48k/Plus, for the grey +2 or the black +2 or +3. I also have a lot of other Spectrum parts, working computers and games for sale. I will happily put together a custom bundle for you.
I will be writing more about more Spectrum power supplies in the near future. Watch this space! Part 3 is now here.