Part 1 – The Keyboard Membrane

A New and Old Keyboard Membrane on a Sinclair ZX Spectrum + (Plus)

By far the most common problem on a Sinclair ZX Spectrum and Spectrum +, is the keyboard membrane. You might be able to get the Spectrum to display the Sinclair Research prompt (see below), but the keyboard may not work at all, or some keys work and others do not.

This is because the keyboard membranes dry out, become brittle and fail with age. It is rare to find an original one that is fully working these days*. And if the membrane is working at first, it will probably not be long before it starts to fail when the Spectrum is started up again, with some keys not working or the ribbons breaking connections with the Spectrum’s printed circuit board (PCB). The ribbons may break when you open up the Spectrum.

In the first photo above of inside a Spectrum + case, the old membrane is shown on top of a new one. The new one has been fitted to the top of the Spectrum + case. The new one is shiny. The old one is dull. The second photo below shows the completed process of fitting the membrane.

The new membrane fitted to the Spectrum +

At PopeyMon, I offer a service to source and to replace faulty membranes with new ones and to service the keyboards on the later models of Spectrum. There is a service that I provide for each model of Spectrum here – click the link:

*There is one exception – those produced by Samsung were higher-quality and last longer. But even these can fail and must be checked.

This procedure is particularly tricky on the Spectrum + and on the Toastrack to get right, and to make sure that all keys are working. The membranes are also more expensive than for the rubber key models. And hence the price difference with the service between the rubber key and +/128k. A photo of the new membrane for the rubber key, being fitted for a PopeyMon customer during a full repair and refurbishment, is shown below.

New Keyboard Membrane

While I have your Spectrum, I can also perform other repairs and refurbishments.

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