Spectrum 48K New overlay, clean up and composite mod

Locally in Australia Sinclair Spectrums weren’t very common. At the time Commodore 64s were the most popular 8 bit computers amongst anyone I knew, followed by Amstrad CPCs with smatterings of other 8 bit micros around. I cannot ever remember seeing a Spectrum for sale locally, although I am sure some places did stock them. As a Commodore 64 owner I was never really fussed by the seemingly limited computer I used to read about in C+VG, but I was intrigued how some games could be so good on the Spectrum, but rubbish on the C64. Chase HQ springs to mind. Anyway I have wanted one for a while now, and a mate manged to snag a couple of Spectrums locally, so he kindly sold me a 48k rubber keyed version. I gotta say, in good condition these look awesome.

So below you can see mine. The keyboard plate is fairly scratched and unappealing. But there is plenty that can be done to make it better!

Spectrum 1 Before



Fortunately you can buy brand new replacements! I opted for an aluminium plate, which I bought from SellMyRetro. There are also vinyl overlays available you can place over an existing plate. These look good and are a bit cheaper, but I wanted something more authentic. After a few weeks the following arrived safely in the post. On the underside there is some adhesive to stick the cover on the spectrum.

Spectrum 2 New PlateSpectrum 3 Under new plate


A common problem with the rubber keyed Spectrums is the keyboard membrane disintegrating and failing over time. Fortunately the one in this unit was good and 100% functional. Taking apart the Spectrum is easy. Simply turn upside down and remove the screws. When removing the top portion, carefully unplug the keyboard ribbon cables from the motherboard. To remove the existing keyboard cover plate you either have one with tabs, or one with adhesive glue. I got lucky and simply had to bend some tabs to remove the plate. If you have adhesive glue holding it on, you will need to slowly heat with a hairdryer and pry. Plenty of info documented online about how to do that. To remove the motherboard from the case, there is a singe screw near the middle. Now the rubber keyboard was filthy and the case could do with a clean, so I gave everything a good wash.

Spectrum 5 cover off Spectrum 6 Dirty rubber keys


Now everything is nice and clean. I clean the keys on everything I get, they can be so gross!

Spectrum 7 cleaned up


While we are at it, lets to a composite mod. It is very simple, with heaps of info online. For example http://www.retrogamescollector.com/simple-zx-spectrum-composite-mod/

We need to get into the RF modulator, which is pictured top left.

Spectrum 8 remove RF lid


Prise the lid off to see inside.

1 – Remove the resistor from the rca plug. I desoldered min and cut the leg back so it would not short on anything.

2 – Remove/ cut the wire as shown.

Spectrum 13 RF mod


Outside the RF modulator:

1 – Remove the wire completely

2 – Remove the 5v wire completely cutting where shown.

Spectrum 14 rf side


Solder a wire to where the wire from #1 was removed above. Thread through the left hand hole. Will need to be aware to use a wire that will fit through the hole.

Spectrum 15 Composite Wire


Solder the wire to the RCA connector as shown below…. and thats it! Conveniently we can use the RCA connector from the RF unit for composite.

Spectrum 16 Composite Wire


So my Spectrum did not come with a power supply. I chose a 9v 3A powerpack. Use a centre negative plug configuration.

Spectrum 4 PowerSupply


Now everything is reassembled. How good does that look!

Spectrum 17 new plate


Finally a pic via composite. Not that exciting, and please excuse the poor picture. In person you can’t see the swirliness that the camera picks up. Future project will be hooking up a Kempston interface and loading games with a tape emulator via phone.

Spectrum 18 com mod


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