My first proper computer was a rubber key ZX Spectrum 48k. This was a very popular choice in the early 1980s and I well remember my Dad bringing it home from Boots one day after it having been on order for a long time. Over the years since I have always hung on to it although following a resurgence of interest in the early 90s I messed around with it a bit which led to me replacing the top with a new keyboard as my original one had become very scratched and the keys stopped working. Also somewhere along the line the motherboard was also changed, so actually there’s not much left of my original machine now.
After digging it out, I was pleased to find it had stayed in pretty good nick. It doesn’t have the original power supply (I remember accidentally melting it when doing some experiments many years ago) but other than that is complete. It started up first time but perhaps predictably the keyboard had failed again.
I remember when this happened to me back in the early 90s, and I had really no idea what had happened or what to do about it. I ended up getting hold of a home-made external keyboard which I found in my school physics lab which worked perfectly, although sadly I no longer have it after a much regretted clearout when I was a teenager and this stuff all seemed so ‘1980s’ and boring.
It’s now very easy to get replacement membranes from eBay and other sellers which are apparently much better quality than the original. Replacing the membrane can be tricky and it depends a bit on how old your Spectrum is and what design was used. The case screws release the keyboard assembly from the top, but the ribbon cables need to be carefully detached from the motherboard by pulling them out.
The actual membrane is underneath the rubber key mat, which is in turn held in place by the metal template which has the key markings on it. On my old Speccy it was held on with double sided sticky tape which was surprisingly difficult to remove and I ended up making a right mess of it with it getting bent out of shape. At some point in the past I swapped out the broken one for a new top casing and on this one there are metal pegs which hold it on which need pulling straight:
Then it’s simply a matter of pulling the old membrane out, threading the tails of the new one through and replacing the rubber mat on the top:
Then it’s simply a matter of putting it all back together again, and as expected everything worked fine. On to the next!
Universal Discovery Methodology 