Some of these blog posts are put together from several Patreon posts, written as I am going along. Sometimes I only end up using bits of those in the posts that end up on here. This is one of those occasions. That was meant to be the main focus of the post, but ended up getting cut out altogether. Well now you can read about it.
When I was writing the post that became "ZX Spectrum future proofing" (http://blog.tynemouthsoftware.co.uk/2023/08/zx-spectrum-issue-2-future-proofing.html), the plan was to feature that as a small part of another post. Just show the voltage regulator and composite mod and get back to the other post, but you know how things go, that one grew into a large post of it's own.
The main feature of the post was meant to be this "Lo-Profile Professional" keyboard I picked up on ebay a couple of years ago that I finally got around to unboxing and trying out.
I had been looking for one of those for a while, as a friend of my Dad's had one of these in the 1980s and I learned BASIC programming on that, so it would be nice to have one of those again.
However this one was listed as "spares or repair", and indeed, is unfortunately an accurate description.
I was aware that there had been some mods made from the pictures in the listing, but I was hoping to be able to cover those, like I did with the Oric Atmos with the big hole in it's case. (http://blog.tynemouthsoftware.co.uk/2022/11/oric-atmos-repair.html)
I had assumed these were from back in the 1980s, but it looks like this might have had more recent work.
I don't have a date for these, but I would guess maybe 5-10 years ago, the website does not seem to be active any more, and the Tindie store where these would have been sold is gone.
It was missing a Spectrum board inside, but I had a ZX Spectrum on the bench needed some work, so I planned to fix up the Spectrum and then test it out in this case.
There is a lot of space in there, I think it would have been intended to fit the power supply inside, and maybe other accessories. (like this one featured in my post on the 80K Spectrum mods - http://blog.tynemouthsoftware.co.uk/2020/03/a-zx-spectrum-with-80k-of-ram.html)
Time to test it out. It is sort of working, but it looks like the keyboard PCB is warped. The key sections screw on and interlock together, and none of them seem to sit properly any more, so don't make good contact.
That is as many keys as I got working. Not sure if I will be able to solve all the mechanical issues to get this going again. (photo taken with the original capacitor composite mod before I redid it with the video buffer board).
Some are missing due to a couple of broken wires on the connectors, others don't sit right and don't register at all. Others had to be removed as if the screws were tightened down, the keys always reads as pressed, so they only work if you partly tighten the screw, which is not really a solution.
I am wondering if I might be able to designed a new keyboard PCB for it?
It's a little strange in that it is single sided, but has overlaid traces on the top to make it dual layered?
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Hope to have a better solution soon.
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