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Sinclair ZX Spectrum Power Supplies – What Types Are There (Part 6)? – The First One? UK1200?

When I started doing the research, opening up lots of Spectrum power supplies, and writing this series of articles, I had thought that the UK1400 power supply was the first one for the Spectrum, as shown below.

Power Supply for Rubber Key and Plus Types of Sinclair ZX Spectrum

But I was told by members of the Spectrum community that there was a UK1200. I had never seen one in the flesh… UNTIL NOW!

I have got one NOW! How exciting!

Model name: UK1200

Input: 240V AC

Output: -12.5V DC approx., unloaded (unregulated), maximum current rating 1.2A (1,200mA and hence the name UK1200).

When under load and being used on a Spectrum, the voltage will be nearer to what is stated on the PSU label.

Polarity: Centre Negative (not positive) Outer Positive (not negative as on most barrel connectors).

Getting the polarity is essential if you do not want to damage your Spectrum.

I do not know whether the UK1200 power supplies are suitable for any other model of Spectrum than the Issue1 Spectrum.

The strain relief on the PSU is not as stiff as on the UK1400. This might mean that it lasts longer because they are notorious for breaking.

It has a barrel connector that is not smooth. The UK1400 that was subject to a safety recall had a smooth barrel and black and white DC cable.

The insides are very similar to the UK1400. It is a full wave bridge rectifier with two smoothing capacitors. And a fuse.

I cannot verify that it the UK1200 would work on an Issue 1, because I do not own one.

However, the fact that the UK1400 power supply followed the UK1200 – or even possibly was being sold at the same time as the UK1200 – suggests that 1.2A was insufficient for the Spectrum and 1.4A was needed.

The UK1200 certainly won’t be suitable for 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.

I would not recommend running any Spectrum with the UK1200 and without an Issue 1, I have no intention to!

And sorry. This power supply is not for sale.

But I do have a range of other power supplies for sale. The series of articles on this website is there to help you choose the right one.

Before use all power supplies need to be checked for safety, as well as functionality and that they are delivering the right voltage levels, current and polarity. So please note that they must be checked before use, and check the Safety article.

If you are looking to buy any 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 would like to credit and highly recommend the excellent videos by “JoulesPerCoulomb” on Youtube. “Greetings and good time of day…” to whoever this mysterious but extremely helpful man, is. His video on power supplies was a brilliant starter a few years ago to the many hours of research that I have conducted since on Spectrum power supplies, and which I present in this series of articles.

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A Look Inside the Original Spectrum Power Supply (16/48k Rubber Key Models)

The UK1400 PSU
The UK1400 Power Supply Unit (PSU)

On this PopeyMon Games and Fun website, in a series of articles I have tried to described all types of power supply unit (PSU) for the Sinclair ZX Spectrum models.

This goes from the first 16k and 48k rubber key models when the Spectrum was owned by Sinclair to the final disk drive version of the Spectrum, the +3 under the ownership of Amstrad. There is an index to the articles, as Part 0 of the series.

In this article, I am delving into the inside of the original Spectrum power supply, the UK1400 model.

I say original, but I’ve been told from several credible sources in the Spectrum community that the Issue 1 Spectrum had a UK1200 model. Until I see one being used on an Issue 1 Spectrum “in the flesh”, I will still call the UK1400 the original Spectrum PSU.

The UK1400 was used for all rubber key models of the Spectrum – 16k and 48k. It was also used on the Spectrum Plus with a different design.

This earlier article also talks about the UK1400. But I want to go a bit deeper here. Here are six images of the components inside the UK1400. As in the earlier article, there are several designs of the UK1400.

They are all implementations to the same specification. And all of them use a full-wave bridge rectification circuit to convert the mains 240V into around 12-14V DC (unregulated and when unloaded) via a barrel connector to the Spectrum board.

Note: A “smooth” barrel connector has been used to replace the original on the photo at the top of the article. Please see the Safety Warning article for more on the UK1400 production that were recalled for safety issues.

Each of the designs meet the UK1400 PSU Specification in different ways.

Some designs are compatible with other designs and some are not.

There are different orientations of the PCB and transformer – some designs have the PCB underneath the transformer and other designs have the PCB at right-angles and to the side of the transformer.

There are different versions of the case, so they are not interchangeable with different designs. Here is one case from a PSU that failed its tests.

And as I have said on other articles, BEFORE you plug any power supply into your beloved Spectrum, please CHECK is it safe to use: (i) for you, (ii) for your Spectrum.

I have TESTED and WORKING PSUs for sale in the PopeyMon website shop and in the eBay popeymon shop too.

If you have any questions, please get in touch.

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Sinclair ZX Spectrum Power Supplies – What Types Are There (Part 5)? – The +3 (Disk Drive Spectrum)

The Sinclair ZX Spectrum +3 (Black)
No Tape but Floppy Drive Instead!

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”).

The Amstrad-Owned Era of the Sinclair ZX Spectrum

Part 3 dealt with just the Grey +2.

Part 4 dealt with the Black +2 (+2A and +2B).

Part 5 deals with the +3, the disk version of the Spectrum.

Like the Grey +2 and the Black +2 – although the case is similar to 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 for the computer came from a lead that went from the monitor to the CPC. There was only one plug.

The +3 has one plug for the computer unit, but you still need a plug for your separate display.

Power Supply for Rubber Key and Plus Types of Sinclair ZX Spectrum

The Black +3 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 a DIN connector, instead of the barrel connector used for the UK1400.

The +3 PSU is much larger than the earlier Spectrum PSUs. The voltages and current rating are shown in the photos above, and described below.

It generates:

  • +5V at 2A
  • +12V at 700mA
  • -12V at 50mA

These are connected to the pins on the DIN connector. Different voltages are needed for different functions of the +3.

The ratings are VERY SIMILAR, but NOT IDENTIAL to the +2 PSU. 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!

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What Kind of Spectrum Would You Like?

An Original 48k Sinclair ZX Spectrum
Refurbished For A Happy Customer

Above is a photo of an original 48k Sinclair ZX Spectrum with the rubber keys, which has been refurbished to a very high standard by PopeyMon Games and Fun.

It was sold in a package which was put together by PopeyMon following a request by a customer for a custom bundle, so that he could get the joy back from having a Spectrum just like the one he had almost 40 years ago. The Spectrum was released in 1982.

It is the customer’s own photo, which he has given permission for me to use. PopeyMon has been given the following endorsement by the customer, Mr. L. Stevenson of Essex:

“I received my Speccy bundle today all packaged and looking amazing… everything is in great working order as promised and I can now enjoy playing my spectrum 48k once again after 40 years! Extremely happy with the service and delivery of such a special machine. Thank you”

PopeyMon has put together many Spectrums, and custom bundles, and many types of Spectrum, for a lot of happy customers over the past two years.

So what kind of Spectrum would you like?

Do you want it to be like the original Spectrum above, or another model as shown below? PopeyMon has expertise in all models of Sinclair ZX Spectrum, in repairing them and refurbishing them.

Would you like it to be refurbished?

If you do want it to be refurbished, you can choose any of the following options, and I will give you a good price on the work and an agreed timescale for delivery. I also package things up properly, as shown in the endorsement above.

The above Spectrum + (Plus) has been opened up, as shown in the last photo. The machines are nearly forty years old now, so it is unsurprising that most will need some work.

This Spectrum + has been refurbished to a very high standard, with the following work done by PopeyMon:

  1. all electrolytic capacitors have been replaced with high quality Vishay capacitors. This is not absolutely necessary, because a Spectrum can operate successfully with the old ones, but they can deteriorate over time with heat, age, usage and under bad storage conditions. They can then damage other components, such as the RAM chips that are more difficult to replace,
  2. a better ULA chip, the 6C0001E-7 model which was the last one for the original rubber key models and Spectrum Plus,
  3. a new modern voltage regulator which means the Spectrum runs cooler and the heatsink can be removed,
  4. a new keyboard membrane, not shown in the photo above. These are manufactured new. The old ones usually dry out and stop working, and the ribbons that attach them to the computer’s board inside, become brittle and break. It is fitted for the customer,
  5. the TV display has been modified to be a composite video output, instead of the traditional
  6. the case and keys have been thoroughly cleaned, including every single key
  7. the edge connector has been tested with a joystick interface and with a modern SD-card solution such as DivMMC, Interface 1.bis or Retroleum Smart Card
  8. very thorough testing

Would you like a repair done? Send me some details of your machine to get the conversation going, with as much detail as you can of the symptoms and photos if possible. I can also do a part-exchange.

Would you like a tape player to load and save games?

Would you like a joystick and joystick interface to play games without using the keyboard?

What games would you like to play? I have a large stock and can get games in for you on commission.

Would you like your power supply checked and refurbished? These are old now. Do you really know that it is safe to use? I am PAT trained and have a lot of experience with these power supplies. I have a comprehensive guide to all Spectrum power supplies on this website. Be VERY careful what you might buy on eBay or cheap from China, without checking. What might seem OK could kill your Spectrum! Do get in touch.

PopeyMon offers all of the above services and products, plus more. I also buy Spectrums and anything Spectrum-related. I offer other products and services too.

Get in touch with PopeyMon – Contact Details at the link – for all your Spectrum needs!

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Sinclair ZX Spectrum Power Supplies – What Types Are There? A Series Of Articles – Part 0 – Foreword and Introduction

The Sinclair ZX Spectrum with rubber keys

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.

The first type was the rubber key 16k and 48k models (as shown in the above photos). Next were the Plus and 128 models during the Sinclair ownership of the Spectrum brand.

Sinclair then hit financial problems. After Alan Sugar’s Amstrad bought the rights to the Sinclair Computer brand, there was the Amstrad ownership of the Spectrum brand.

And now, in the present, we have the new Spectrum Next. This latter era may be added in the future.

The Sinclair-Owned Era of the Sinclair ZX Spectrum

Power Supply for Rubber Key and Plus Types of Sinclair ZX Spectrum

The power supply unit (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.

Spectrum Plus version of the UK1400 Power Supply

The PSUs for these models are interchangeable. However, with the models after these, it becomes more complicated.

The articles in this series explain more about compatibilities and incompatibilities, especially in the Grey +2 article (Part 3), after the initial models have been introduced.

Part 1 of the Series looks at the rubber-keyed Spectrum and Spectrum + (Plus) and is here.

The Sinclair ZX Spectrum 128 “Toastrack”

Part 2 of the Series deals with only the 128 a.k.a. “Toastrack”, so called because of the huge black heat sink on the right-hand-side of the case. This was the last Sinclair-owned model of the Spectrum.

The Amstrad-owned Era of the Sinclair ZX Spectrum

Sinclair ZX Spectrum +2 (Grey)

Part 3 looks at the first Amstrad-era Spectrum, the Grey +2. Some people view this machine as half-way between the Sinclair and Amstrad eras of the Spectrum, due to the combination of the new case and old 128 board inside. But the PSUs are NOT swappable, as they produce different maximum power outputs and the machines have different power consumption. More info is in the article, as well as information about compatibilities and incompatibilities.

The Sinclair ZX Spectrum +2 (Black)

Part 4 deals with the Black +2 models, the +2A and +2B. These models are more Amstrad-influenced, with the power circuit totally removed from the main board and placed into an external “power brick”.

Sinclair ZX Spectrum +3 (Disk Version)

Part 5 will look only at the +3, the disk version of the Spectrum. This was the last model designed BITD (Back In The Day), but was not the last released, because of the +2A/+2B/+3A/+3B versions that were released at different times. This article has not been completed yet.

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 and have done so for my customers – please see my Feedback on the About page.

PopeyMon Games and Fun
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Manic Miner For Collectors (Part 0) – Foreword and Introduction

Manic Miner for the Spectrum and MSX
It was released for many other platforms
with many variants

Manic Miner is one of the classic computer and video games of all time.

It was released on the Sinclair ZX Spectrum and for many other platforms with many variants, releases and editions.

But as it stood in late 2020, it appeared that those variants, releases and editions were not documented in any one place.

Collectors love variants and so PopeyMon Games and Fun wanted to perform this service for the gaming community and the Spectrum community.

The series of articles on Manic Miner for Collectors is based on the research by collector and expert Adrian Grubb, seen by many as the authority on Manic Miner versions and passionate collector of all things Manic Miner.

Adrian’s research was reviewed over many years by a great many people on the Central Cavern Facebook group. PopeyMon got Adrian’s permission to use and edit the articles, and to publish them on the web, with his photos. Before these articles were published, Adrian reviewed them for correctness and completeness (see footnote *).

The articles deal only with the Sinclair ZX Spectrum releases of Manic Miner. The articles do not look at the internals of the game itself – only the inlay, cassettes, boxes and covers and the variants of these in the editions and releases for the Spectrum.

Part 1 of the Manic Miner For Collectors series is about the First Edition, First Release on Bug Byte – the so-called “Whistler” version. See Footnote*.

Part 2 was on the First Edition, Second Release that was also from Bug Byte, the so-called “Lantern” version. See Footnote*.

Part 3 is about the version that was released on the Software Projects label, the “mutant telephone” release.

The game was released on many other platforms, including the MSX (er… pun intended for this platform game!), as shown in the photo above. These articles do not look at those platforms, although there might be updates in the future.

I have had a request to do a series for the Horace games. Look out for that soon! 🙂

PopeyMon Games and Fun

Footnote*.

Please note that every effort has been made to check the information in these articles. They were reviewed by Adrian Grubb and altered to update them, before publication.

During a review of the articles on the Central Cavern Facebook, and when published via Twitter, there was a lot of very positive feedback from fans.

These articles are published to fill a gap in knowledge for collectors, and are provided in good faith. If you believe that you have evidence that there are inaccuracies, please get in touch at the contact details here.

Controversy? Following many years of enthusiasts discussing the game in a civilised manner, and there being an established view based on Adrian’s work, one person, who shall remain nameless at this point, got in touch with PopeyMon and Adrian via Facebook and broadcast a berating attitude via Twitter.

Instead of praising the work, this person made a series of unsubstantiated claims in relation to the order of the first two releases. His approach was not to approach PopeyMon or Adrian in private, but to heavily criticise the work in public. This is not how the Spectrum community usually behaves.

Sadly, it appears that this approach greatly upset Adrian, meaning that Adrian deleted the original articles and an Admin switched off comments on the post in the Facebook group. Meaning that discussion could not take place.

PopeyMon will be getting in touch with this person, in private, to see if he can provide evidence of his claims. At present, all that can be seen are anecdotes and claims, but if evidence is presented, perhaps the articles will be updated.

Collecting should be a pleasure, and these articles are provided in good faith for collectors to refer to, and the accuracy thereof will continue to be a work in progress. The Spectrum community is very good natured and always has been. It will remain that way, despite a few who might not display the traditional attitude, from time to time.

PopeyMon Games and Fun.

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Sinclair ZX Spectrum Power Supplies – What Types Are There (Part 4)? – Black +2

The Sinclair ZX Spectrum +2 (Black)
a.k.a. +2A/+2B – SPANISH VERSION SHOWN

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.

Power Supply for Rubber Key and Plus Types of Sinclair ZX Spectrum

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.

Spectrum Plus version of the UK1400 Power Supply

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.

It generates:

  • +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!

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Sinclair ZX Spectrum Power Supplies – What Types Are There (Part 3)? – Grey +2

The Sinclair ZX Spectrum +2 (Grey)

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”).

This article talks about the first Spectrum of the Amstrad era – the Grey Sinclair ZX Spectrum +2. The Grey +2 is not to be confused with the “Black” +2 which can look like it is grey, and vice versa, depending on the light and the photos.

They are quite different machines, with the Grey PCB being closer to the Toastrack PCB than the later +2 and +3 (Black) models.

For this reason and possibly some others, some people might consider the Grey +2 to be more of a Sinclair-era Spectrum than an Amstrad-era Spectrum. But there are significant other differences.

The Grey +2 includes a “proper” keyboard, a much larger case, and a tape player (“Datacorder”) built-in. It also 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.

However, it is more like the Amstrad CPC 464 in its external design. Unlike the earlier Spectrum models, its case was not designed by Rick Dickinson.

Although the case is like the 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 an external display.

Power Supply for Rubber Key and Plus Types of Sinclair ZX Spectrum

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.

Spectrum Plus version of the UK1400 Power Supply

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.

Why? Because the power requirements of the Toastrack and Grey 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 +2 Grey needs more than 1.4A. It also needs more than 1.85A, so the Toastrack PSU is not suitable for the Grey +2.

The Grey +2 power supply can deliver more current. It can give 2.1A. Here is a photo:

Spectrum 128 “Toastrack” Power Supply

You can see in the photo above that the case is grey and has the textured right-hand-side, which is different to the Spectrum Plus UK1400 PSU. It is very similar to the Toastrack PSU, but grey instead and with a different label.

Underside of the Grey +2 PSU

On the underside of the PSU, you can see in the photo above that there is no model number and the maximum current is 2.1A. The label is quite different to Sinclair-era PSUs.

Compatibilities and Incompatibilities Between Spectrum Power Supplies

The Grey +2 power supply can deliver a maximum of 2.1A. Its barrel connector is similar, although it is slightly different. It has the same polarity as the Spectrum 128 Toastrack, the Spectrum Plus and the rubber key 16k and 48k Spectrum. So it can be used on these models.

However, the reverse is not true. The PSUs for the rubber key, Plus, Toastrack Spectrums cannot be used on the Grey +2. It needs too much current, so they may fail, especially when the +2 is using the tape player and/or using peripherals.

The Toastrack PSU is compatible with the rubber key Spectrums and the Plus, because it can deliver more current than they use, even with peripherals. But to say again – not on the Grey +2.

The Grey +2 PSU cannot be used on the Black +2 or +3. For a start they have a DIN connector, and internally to their power supplies, as well as inside the computer, they are very different.

In the photos above, you can see that the Grey +2 PSU is very similar to the earlier versions of the Spectrum PSU. But not the same. It is a full wave bridge rectifier.

The manufacture is superior to many of the UK1400’s that I’ve opened up. It is safer, due to the mains wires being insulated well, plus there is a clamp and the terminals are soldered to the wires at the bottom of the case. Not all UK1400 designs have a clamp, although some do. On the UK1400, the mains wire connects on the top of the transformer. The PCB soldering on the Grey +2 PSU is also superior. But these are just two examples of a superior PSU. And so it should be, it is years after the first Spectrum.

Apart from the colour of the case, and minor other design differences inside, the Grey +2 is very similar to the UK1850 (for the Toastrack). BUT THE MOST IMPORTANT FACTOR IS THE MAXIMUM CURRENT RATING – it is lower on the Toastrack PSU than on the Grey +2 PSU.

Again – please carefully check the compatibilities stated above, to avoid ruining your PSU and/or your Spectrum!

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!

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Sinclair ZX Spectrum Power Supplies – What Types Are There (Part 2)? – The Toastrack

The much sought-after Sinclair ZX Spectrum 128 “Toastrack”

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.

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 left and right hand sides of the Spectrum 128 Toastrack
Power Supply for Rubber Key and Plus Types of Sinclair ZX Spectrum

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.

Spectrum Plus version of the UK1400 Power Supply

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:

Spectrum 128 “Toastrack” Power Supply

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.

Underside of the Toastrack 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.

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Sinclair ZX Spectrum Power Supplies – What Types Are There (Part 1)?

A Sinclair ZX Spectrum Issue 3B with DC-DC Circuit Modification
Refurbished by PopeyMon Games and Fun

Above is the inside of a Sinclair ZX Spectrum, the Spectrum Plus. It has a refurbished Issue 3B PCB. This Printed Circuit Board (PCB) was repaired, refurbished and enhanced by PopeyMon Games and Fun, including the DC-DC Mod that makes the power supply circuit more reliable.

It is also installed with new, quality Vishay electrolytic capacitors and a modern switched voltage regulator. The heat sink has been removed, because the original 7805 regulator and Sinclair power circuit and supply design was the source of most of the excess heat.

PopeyMon has refurbished and sold many Spectrums of all types. Another example of a 16k Spectrum is shown in this article here. These machines are sold directly if you use the Contact details here or via the PopeyMon eBay shop. I have games, joysticks, interfaces and more and will happily put a bundle together for you.

There are several types of Sinclair ZX Spectrum. The Spectrum Plus is simply a new case for the same PCB as the 16k and 48k rubber key Spectrum.

So it follows that there are several different types of power supplies for the Sinclair ZX Spectrum. The Sinclair UK1400 PSUs for the 16k, 48k and Spectrum Plus are interchangeable.

Power Supply for Rubber Key and Plus Types of Sinclair ZX Spectrum

The Spectrum ranges from the rubber key 16k and 48k models during the Sinclair ownership of the Spectrum brand, as shown in the photo above, 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 talks about the first Spectrums of the Sinclair era. This includes:

  • the rubber key Sinclair ZX Spectrum with 16k of RAM
  • the rubber key Sinclair ZX Spectrum with 48k of RAM
  • the hard key Sinclair ZX Spectrum + (Plus) with 48k of RAM and black case
  • the Sinclair ZX Spectrum 128 (a.k.a. “Toastrack”), although only briefly, in relation to the earlier PSUs. A separate article is forthcoming soon.

The power supply (PSU) shown in the photo above is a UK1400 model. They may also have found their way to be used on a Spectrum Plus, although the official Spectrum Plus PSU comes in a different case that matches Rick Dickinson‘s superb design of the Plus machine itself.

Spectrum Plus version of the UK1400 Power Supply

The rubber key PSUs and the Spectrum Plus PSU are interchangeable, because the Spectrum Plus is the same machine inside, with a new case, keyboard and reset button. They all have the same polarity, voltage and current delivery.

Model name: UK1400

Input: 240V AC

Output: -12.5V DC approx., unloaded (unregulated), maximum current rating 1.4A (1,400mA and hence the name UK1400)

Polarity: Centre Negative (not positive) Outer Positive (not negative as on most barrel connectors)

As noted elsewhere, the polarity of these PSUs is unusual – centre negative, outer positive. It is essential that this is correct, and many so-called “replacement” PSUs available have centre positive. Getting this wrong could seriously damage your Spectrum!

Years ago, I bought one from a bad seller on eBay who claimed it was compatible. When I challenged him after receiving it, he said it was suitable. BUT IT WASN’T. Don’t worry, I did not put my beloved Spectrum in danger. I got a refund. He changed his mind when I challenged him with the technical facts.

The UK1400 power supplies are not 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.

Why? Because the power requirements of the Toastrack and Grey are higher than the 16/48 and Plus. They require more current than the UK1400 can deliver.

This 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).

There was a potentially very serious fault with the design of the UK1400 (see Safety article at the link), and there are several different designs of the UK1400. Below is a comparison of two PSUs that show one design of the case and of the internals:

Both of these examples are an implementation of a full wave bridge rectifier with single smoothing capacitor. You can see that even within the same design, there are variations:

  1. Ignoring the rubbing off of the red paint on “ZX POWER SUPPLY”, the labels are different between the two PSUs. To give just two differences, although there are more, one has one style of the Class 2 symbol (the square inside a square), but the other a different style. One has the model number UK1400 underlined, but the other does not. While these may be superficial differences, they show variations even before you get inside the PSU. It is believed that different contractors came up with different designs to deliver the specification given by Sinclair in their contracts – something evidenced by the fact that there was a recall (see the Safety article).
  2. Inside the PSU, there are variations even within the same design. The design in these two examples has the PCB mounted at right angles to the transformer, whereas other designs has the transformer mounted top-down on top of the PCB. The internals of the case are different between designs, so the designs are not necessarily interchangeable internally, because the mounts and orientations are different.
  3. The side-mounted PCB on the left-hand-side (LHS) is different to the PCB on the right-hand-side (RHS). One has the components on side one side, and the other has them installed differently. The capacitor is mounted differently too.
  4. The transformer blocks are of different manufacture. One has foam on top (believed to avoid hum when operating), the other does not.
  5. The RHS PSU shows the notorious problem of the strain relief breaking. The previous owner has just “tied a knot” on the inside of the case. This is not good. It can be repaired using a clever design with heat-shrink tubing, or a replacement DC cable could be installed by someone who takes care. I have done this.
  6. Both of these PSUs are faulty and have failed the PopeyMon functional and/or PAT (electrical safety) tests, so are not for sale. Only when they have been fully repaired and tested would they be put for sale. I have sold many of these.

So you can see that:

  • There are a variety of designs of the Sinclair ZX Spectrum over the years.
  • There are a variety of power supplies for those designs of Spectrum.
  • And even within those types of power supply, there are variations.

Collectors love variations. They show the history of the Spectrum, its quirks and foibles, and people absolutely love the Spectrum. I am only showing just one implementation for one design of PSU for the 16/48 Spectrums, which I already have said, is also suitable for the Plus. There are other designs, which I have not shown here.

Once again, please see my other article on the Safety of these models. There are many of these power supplies still lying in people’s lofts, or kept nice and dry in an original box, or at the bottom of a wet shed.

Before use, in any of these cases, they need to be checked for safety, as well as functionality and that they are delivering the right voltage levels, current and polarity. So please note that they must be checked before use, and check the Safety article.

If you are looking to buy one 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. Watch this space! Part 2 is now here.

I would like to credit and highly recommend the excellent videos by “JoulesPerCoulomb” on Youtube. “Greetings and good time of day…” to whoever this mysterious but extremely helpful man, is. His video on power supplies was a brilliant starter a few years ago to the many hours of research that I have conducted on Spectrum power supplies, and which I present in this series of articles.