ZX Spectrum Plus / 128k keyboard

A place to discuss the ZX80's and ZX81's younger brother - the Sinclair ZX Spectrum
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PokeMon
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ZX Spectrum Plus / 128k keyboard

Post by PokeMon »

Due to a request on the german board I am actually working on a keyboard pcb with tactile switches for the ZX Spectrum Plus and Spectrum 128k models. This should be available in mid of december I think - just in case there may be interest in these boards here, too. It will cost a bit more than the standard spectrum keyboard as there are more switches and some additional components on the backside (analog switches and some diodes). The difference to the 48K-KDLX would be a few pounds only, I think.

The pcb replaces the plastic or metal plane at the backside of the keyboard (no need together with the stable pcb) depending on the version of the corresponding models.
48P-KDLX_BS.gif
48P-KDLX_BS.gif (27.16 KiB) Viewed 3456 times
48P-KDLX_TS.gif
48P-KDLX_TS.gif (9.36 KiB) Viewed 3456 times
48P-KDLX_TC.gif
48P-KDLX_TC.gif (35.9 KiB) Viewed 3456 times

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1024MAK
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Re: ZX Spectrum Plus / 128k keyboard

Post by 1024MAK »

Hmm, I have some ZX Spectrum+ machines awaiting keyboard repairs. I would be interested in one of these to try ;) :D

Mark

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PokeMon
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Re: ZX Spectrum Plus / 128k keyboard

Post by PokeMon »

So the first test of the circuitry looks good - not 100% passed as my magnifying lamp died and need a new luminescent tube.
Hard for me to work without. :shock:

I did the calculation of the project and the board is bigger than the 48K-KDLX and has about 50% more tactile switches.

The complete set (construction kit) consists of
2 layer pcb, 256x99 mm (10.0 x 3.9 inches)
58 ALPS tactile switches SKQGFAE010
2 flat cables to connect keyboard to the molex receptacles
5x 74HC4066 analog switches
4x BAT54A duplex diodes
11x BAT54C duplex diodes
1 capacitor 10uF/16V
4 resistor network 5x 100k

The complete set will be offered for GBP 24.00 nominal price on sellmyretro later and all preorders will have a discount of 20% which results in effective price of GBP 19.20. I think this is a fair deal for all supporters of this project. Shipment will be GBP 2.90 for all international orders.

Schematic is attached here as well.
All people interested in preorders may leave an informational post here or give me just a PN. Thanks.
Expected to be available for delivery in mid of december.
Attachments
48P-KDLX - Schematic.pdf
(178.03 KiB) Downloaded 223 times

XorA
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Re: ZX Spectrum Plus / 128k keyboard

Post by XorA »

Looks good, I have at least one of those machines that needs a new membrane anyway so Ill take one!

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PokeMon
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Re: ZX Spectrum Plus / 128k keyboard

Post by PokeMon »

OK - thanks. 8-)

fatbob_gb
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Re: ZX Spectrum Plus / 128k keyboard

Post by fatbob_gb »

I am interested in one please.

XorA
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Re: ZX Spectrum Plus / 128k keyboard

Post by XorA »

BTW if you did a QL version I bet you would get interest. The default QL keyboard is truly horrible :-D

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PokeMon
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Re: ZX Spectrum Plus / 128k keyboard

Post by PokeMon »

Well - I think about changing my name from PokeMon to KeyboardMan. :mrgreen:

XorA
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Re: ZX Spectrum Plus / 128k keyboard

Post by XorA »

PokeMon wrote:Well - I think about changing my name from PokeMon to KeyboardMan. :mrgreen:
Gotta catch them all!

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