dk'tronics 4K Graphics ROM

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Alistair
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dk'tronics 4K Graphics ROM

Post by Alistair »

Got the above chip in my ZX81. Not sure if it's a common thing or not but it was installed by a mate whose ZX81 I bought when he moved on to being a Spectrum owner.

The manual indicates that there are 8 separate graphics character sets that can be used (including the standard Sinclair set) and also the ability to create two sets of user defined graphics.
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mrtinb
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Re: dk'tronics 4K Graphics ROM

Post by mrtinb »

Martin
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Alistair
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Re: dk'tronics 4K Graphics ROM

Post by Alistair »

Yep, that's the one, based on the manual I have.
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gammaray
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Re: dk'tronics 4K Graphics ROM

Post by gammaray »

Are there complete schematics available? I saw some through the link but not sure if that is enough to reproduce.
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XavSnap
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Re: dk'tronics 4K Graphics ROM

Post by XavSnap »

Are there complete schematics available?
It's a basic ROM expansion, base on the $2000 offset.
A single IR redirection to the $2000 memory bloc.

Just get a ROM expansion card set at $2000 to $3FFF (low memory)
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XavSnap
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Re: dk'tronics 4K Graphics ROM

Post by XavSnap »

Internationals pictures...
xur3.JPG
xur3.JPG (51.2 KiB) Viewed 4803 times
xur1.JPG
xur1.JPG (69.9 KiB) Viewed 4803 times
xur2.JPG
xur2.JPG (72.15 KiB) Viewed 4803 times
Xavier ...on the Facebook groupe : "Zx81 France"(fr)
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1024MAK
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Re: dk'tronics 4K Graphics ROM

Post by 1024MAK »

gammaray wrote:Are there complete schematics available? I saw some through the link but not sure if that is enough to reproduce.
I have reverse engineered a schematic, but it only exists as a hand drawn draft on paper at the moment. When I have time, I will redraw it in a CAD program and then post it in this thread. You will have to wait for a while though, as I am rather busy at the moment.

Mark
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sirmorris
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Re: dk'tronics 4K Graphics ROM

Post by sirmorris »

Is it done yet?
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1024MAK
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Re: dk'tronics 4K Graphics ROM

Post by 1024MAK »

:lol:
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp

:!: Standby alert :!:
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb :!:
Looking forward to summer later in the year.
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XavSnap
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Re: dk'tronics 4K Graphics ROM

Post by XavSnap »

but it only exists as a hand drawn draft on paper at the moment.
This ????
mak.jpg
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Xavier ...on the Facebook groupe : "Zx81 France"(fr)
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