Fuller FD42 Keyboard

Discussions about Sinclair ZX80 and ZX81 Hardware
Tezz
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Re: Fuller FD42 Keyboard

Post by Tezz » Thu Jul 26, 2018 1:40 pm

Thanks for all the replies, I was originally thinking of having a board professionally made but going back to it now I think it should be relatively straight forward to hack one together with strip board sections and a couple of edge connectors. The stumbling block for me could be the vertical connector. I suppose I can epoxy that in place and connect everything with some jumper wires. Perhaps I could also add some brackets to nut and bolt the edge connectors together to make sure they withstand use.

Tezz
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Joined: Thu Mar 09, 2017 8:28 pm

Re: Fuller FD42 Keyboard

Post by Tezz » Thu Jul 26, 2018 1:42 pm

1024MAK wrote:
Thu Jul 26, 2018 7:42 am
If you ask PokeMon, he may be able to supply just the PCB from his extender (see here or search these forums). PokeMon is a member here.

I don't know how suitable it would be for the purpose that you want it for...

Mark
Thanks Mark the parts of the extender board should be perfect for the job.

Tezz
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Re: Fuller FD42 Keyboard

Post by Tezz » Sat Jul 28, 2018 1:14 pm

Hi all,

I've been chatting with Charles in a PM regarding the adapter where he mentioned his TAZ adapter. Charles made a suggestion to look at making a generic adapter with a flex ribbon cable so that it could be oriented in any computer case which sounds like a much better plan.

I did start to vector draw the original Fuller adapter last year prior to actually creating the PCB design in the software (which is all new to me)
pcb_wip.png
WIP Fuller adapter
With the Fuller case and it's internal vertical connector I suppose the adapter could be mounted that way with perhaps a plug in cable in the design to pass through to a second edge connector mounted on the back of the case to replicate the setup of the original adapter.

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gammaray
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Re: Fuller FD42 Keyboard

Post by gammaray » Sat Jul 28, 2018 2:50 pm

I would expect a thicker gauge ribbon necessary and maybe some others have some idea what exactly would be adequate for bus signals.

Personally I am looking at changing the the bus connector to a 2x25 female header instead of card edge and matching with a 2x25 shrouded or box male header connector for peripherals. (Mechanical forming of pins to match current card edge connector pin spacing would be needed)

Permanently soldering the 2x25 female to the main board is my planned conversion for one of my designpaths. But I can see stress on connecting and disconnecting joint may become a problem. Long term use will tell how reliable. I am also interested in determine if there is "rampack wobble" failure with this approach. I would expect none.
5-TS1000,UK ZX81<-Sheelagh, US ZX81, 2-TS1500/KDLX , 3-TS2040 printer, 2-TS2020 cassette decks, ZXPAND+AY, ZeddyNET, ZXBlast, UDG, ZX8CCB, AERCO, BUILDS/REPAIRS ZX Spectrum, ZX80 Minstrel, ZXMAX48 v1 v2, 2-TS-2068, ROM, 16kRAM

Tezz
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Re: Fuller FD42 Keyboard

Post by Tezz » Fri Oct 12, 2018 4:31 pm

Hi all,

Does anyone actually have the correct dimensions of the original Fuller extension board? I will look at making a card template at the weekend to try to judge the size using the photos for reference.

thanks,
Tezz :)

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gammaray
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Re: Fuller FD42 Keyboard

Post by gammaray » Sat Oct 20, 2018 5:24 am

Rectangular version of PCB
FD42 KEYBOARD adapter.jpg
5-TS1000,UK ZX81<-Sheelagh, US ZX81, 2-TS1500/KDLX , 3-TS2040 printer, 2-TS2020 cassette decks, ZXPAND+AY, ZeddyNET, ZXBlast, UDG, ZX8CCB, AERCO, BUILDS/REPAIRS ZX Spectrum, ZX80 Minstrel, ZXMAX48 v1 v2, 2-TS-2068, ROM, 16kRAM

Tezz
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Re: Fuller FD42 Keyboard

Post by Tezz » Sat Oct 20, 2018 1:50 pm

Thanks Charles, the vertical connector is visible in that photo so that's helpful to see.

For anyone else interested also, here's the card template I made last week compared with an actual Fuller extension so I now have the dimensions to start to work on the PCB design in my attempt to replicate it. (the issue 3 board in my half of the photo is a little lower than its correct position as I've not yet drilled the holes for the ports in the Fuller case in that orientation)
fd42 template compared with genuine extension.png

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gammaray
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Re: Fuller FD42 Keyboard

Post by gammaray » Sun Oct 21, 2018 5:04 am

Enclosed is EASYEDA straight thru pcb file done the hard way. No way to mount internally to case. The way I did it with my own library entry also prevented me from easily modifying the bus traces. Will try again using different tools... (Maybe I should do a UTUBE video on how maybe not to layout)

Charles
Attachments
FD42_MAINBUS_STRAIGHT_THRU.json.TXT
(179.73 KiB) Downloaded 15 times
5-TS1000,UK ZX81<-Sheelagh, US ZX81, 2-TS1500/KDLX , 3-TS2040 printer, 2-TS2020 cassette decks, ZXPAND+AY, ZeddyNET, ZXBlast, UDG, ZX8CCB, AERCO, BUILDS/REPAIRS ZX Spectrum, ZX80 Minstrel, ZXMAX48 v1 v2, 2-TS-2068, ROM, 16kRAM

Tezz
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Re: Fuller FD42 Keyboard

Post by Tezz » Sun Oct 21, 2018 5:43 pm

Great stuff, thanks Charles that's much of the design prepared. I'd forgotten that I did find a low resolution photo online last year showing the vertical connector. I will need to create that vertical edge connector part attached to the same PCB design so that it can be sawn off and then soldered in place on the main extension PCB and it should then be good to go. PCB design is all new to me, I guess the vertical connector will need to be manually connected to each trace with individual wire jumpers? or perhaps the traces can just be connected with a simple solder joint between them and some kind of mechanical attachment to ensure it's strong enough to withstand plugging expansions in and out such as a nut and bolt on both sides of the connector.
fuller-zx81-extended.png

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1024MAK
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Re: Fuller FD42 Keyboard

Post by 1024MAK » Mon Oct 22, 2018 2:32 pm

I suggest you use a 2.54mm double row pin header on the larger board with the smaller board soldered in between the two rows of pins.

The track layout on the main board would need to be arranged to accommodate the through holes that the pin header will fit in.

Mark

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