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.
Part 1 of the PopeyMon articles on the types of Spectrum PSU talked about the rubber key models and the Spectrum Plus. Part 2 dealt with just the Spectrum 128 (“Toastrack”). Part 3 dealt with just the Grey +2.
This article talks about the second Spectrum of the Amstrad era – the Black Sinclair ZX Spectrum +2. Two models exist of the Black +2 – the +2A and the +2B. Both models use the same power supply.
The Black +2 is not to be confused with the Grey +2 as it can look like it is (dark) grey, and vice versa, depending on the light and the photos.
Although they look quite similar on the outside, they are quite different machines “under the hood”, with the Black +2 PCBs being very different to the Grey +2 PCB, which is closer to the Toastrack PCB and therefore the Sinclair-era models of Spectrum.
Like the Grey +2, the Black +2 includes a “proper” full-sized hard keyboard, a much larger case than the Sinclair-era machines, and a tape player (“Datacorder”) built-in. Also like the Grey, it includes two joystick ports, plus more ports on the back that include an RGB display output as well as the normal RF output. This latter similarity is like the Toastrack and Grey.
Again, like the Grey +2 – although the case is like the Amstrad CPC, the power still comes from an external power supply. On the original design of the CPC, there was only one plug, for the monitor and computer. The power came from a lead that went from the monitor to the CPC. And unlike a lot of Amstrad’s products that only needed one plug (including the CPC), the Grey +2 needs more than one plug, because it needs a plug for the external display as well as the computer unit.
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.
None of the UK1400 power supplies above are suitable for any other model of Spectrum – not the 128 “Toastrack” and not the (Amstrad-era) Spectrum +2 Grey. And definitely not the Black +2 or +3.
Why? Firstly, the connector is totally different – the Black +2 uses a DIN connector and not a barrel connector.
Secondly, the PSU and main board of the Black +2 are very different to the Sinclair-era Spectrum models. The DC-DC conversion circuit that caused so many problems on the Sinclair-era machines (and still does!), has been removed. And the work is now done in the PSU itself. However, there are quite a few problems with the Black +2 PSU, that you need to be aware of. If you are not sure, do not do the work yourself. Get in touch with PopeyMon.
The Black +2 PSU could be referred to as a “power brick”, like the Xbox 360 PSU. It is very heavy. It generates the voltages on different lines to the DIN connector.
It is much larger than the earlier Spectrum PSUs. The voltages and current rating are shown in the photos above.
- +5V at 2A
- +12V at 200mA
- -12V at 50mA
These are connected to the pins on the DIN connector. Different voltages are needed for different functions of the Black +2.
As will be seen in the final article of the series, Part 5, the +3 disk model of the Spectrum, has a similar power supply. But the +3 needs more current, so the +3 power supply can be used on a Black +2. BUT NOT THE OTHER WAY AROUND. The Black +2 PSU should NOT be used on a +3.
This article will be updated with some photos of the internals, in the near future.
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 the Spectrum power supplies in the near future. This series will conclude with the Amstrad-era models of the Spectrum, the Black +2 (Part 4) and the +3 (Part 5). When I finally get my Spectrum Next (that I’ve already paid for via the Kickstarter 2), I might even do an article on that, too! Watch this space!
P.S. According to one Speccy fan, it appears that the rare Issue 1 Spectrum used an earlier version of the power supply, not the UK1400. And according to the great JoulesPerCoulomb on Youtube, even a UK700 was used. But as I’ve said elsewhere, you cannot trust either the original manufacturer, or other people who may have fiddled around with the PSU before you got it. So you need to check in all cases, no matter what the label on the PSU claims!