Sharp PC-3000

Everything about vintage DOS based Palmtops goes in here...
Kyodai
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Re: Sharp PC-3000

Post by Kyodai » Wed Nov 09, 2016 4:50 pm

1. I need to rewrite that paragraph i think. The Sharp definitely will NOT boot from Flash or CF since it needs a driver to utilize these. Also if i remember right it will not boot MS-DOS 6.2 due to some BIOS limitations. I think it could handle DOS 5.0 though. I should play with it again before i rewrite the article. I think it's more than a decade since i last played much with the Sharp.

2. Officially the PCMCIA CF adaptors are "too big" for the slot, but they do fit, even if it's a bit tight. They really just need the drivers.

3. Basically you put the drivers in the local config - you can edit the autoexec.bat and config.sys in Drive D:. As you noticed this works as long as the RAMdisk doesn't get erased or you lose all power.

4. The installer should let you pick the machine type - Sharp PC-3000 is an option, so it's kinda all-automatic for these machines.

5. DOS 3.3 will not be able to handle anything over 32MB. So as it is the 128MB card will not work. Maybe you can partition it and make the first partition 32MB? I haven't tried that though, but i think out-of-the-box the SHarp will prolly treat it as an "Invalid drive". At least I'd expect that.

wintermute
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Favorite Palmtop: Sharp_PC-3000

Re: Sharp PC-3000

Post by wintermute » Wed Nov 09, 2016 6:27 pm

Great, thanks!

Now I am just hoping the HP Omnibook 800ct will be able to read/write both SRAM and the CF card.

Will get a 32MB CF card in the meantime.

Cello
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Favorite Palmtop: SharpPC3100

Re: Sharp PC-3000

Post by Cello » Wed Nov 09, 2016 8:05 pm

Hi Kyodai,

I hope your still monitor this thread.
As a happy owner of a Sharp PC-3000 and a PC-3100 I am really glad I stumbled upon this forum.
But my fear seems confirmed: there is no way the Sharp can use an ordinary PCMCIA-card (or a CF-card in a convertor) unless you first put drivers on it. In order to put drivers on this machine, you need to have a RS232-connector or a SRAM card. I have neither.
SRAM-cards are ridiculously expensive on eBay and RS232-connectors are impossible to find.
So there seems to be only one solution left: to build my own RS232-connector. Tried, but I cannot find any PCB-board that has the correct thickness to fit into the female connector socket.
So ... any help is appreciated.

PS: fabulous collection you list on your site

Cello

Kyodai
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Re: Sharp PC-3000

Post by Kyodai » Wed Nov 09, 2016 9:43 pm

Hi Cello,

thanks for the kind words!

Yeah it's that kinda "bootstrapping" problem, to pull yourself out of a swamp just by pulling the bootstraps.

About the PCB - I would just get one that is a bit thinner. Then you could put "Silver epoxy" on it to make for the contacts, just paint a thick layer of silver epoxy on both sides. After it has dried you can sand it down and cut out the actual contact lines with a sharp knife.

I also thought about the possibility to use DEBUG.EXE to create the flash driver from a listing which would be annoying work, but the only solution to bootstrap the Flash driver out of thin air if you have nothing else but a CF pcmcia adaptor.


Unfortunately that is nearly 400 lines to enter in DEBUG.EXE - probably hours of work, but imho the only solution to get a flash driver (dipssdp.sys) without any other hardware.


http://www.tankraider.com/userup/1478777383.zip


And if you wanna get some training first - here is a VERY short listing to create a little program that lets the speaker beep a bit.

http://www.tankraider.com/userup/1478770644.zip


Let me know if you have better ideas or need more help.



Edit: I tried to compress the driver with UPX and create a new listing. gets it down to under 260 lines. Still enough to make me crazy when i have to input all by hand. I wanted to try it in my Sharp, but guess what - batteries are empty! XD Maybe imma have time to get new batteries and play with it on the weekend.

wintermute
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Favorite Palmtop: Sharp_PC-3000

Re: Sharp PC-3000

Post by wintermute » Thu Nov 10, 2016 3:06 am

Wow, some hard-core stuff here! It is actually a very clever idea and I used to type in much much bigger programs into various 8-bit computers back in the '80s. I might even try this if the Omnibook doesn't save me! :)

EDIT: I typed in your small example and it doesn't beep on my Sharp (yes, all sounds are on)

Kyodai
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Re: Sharp PC-3000

Post by Kyodai » Thu Nov 10, 2016 8:20 am

Well i got the files from here:

http://www.angelfire.com/electronic2/pc3k/pc3k.html

On the bottom of the page is the makedbg program and description. Maybe I'll try it myself i have time (and fresh batteries) this weekend.

Cello
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Favorite Palmtop: SharpPC3100

Re: Sharp PC-3000

Post by Cello » Thu Nov 10, 2016 8:43 am

Wow, those are prompt replies.
Love the internet that enables us to share info on 24 old machinery we respect.

Good idea about entering code in DEBUG. I completely forgot about that alternative. I now remember once doing it for the Atari Portfolio which has a similar Catch-22 problem.
Will try PCB first with your advice to use Silver Epoxy.

Till now I was looking for PCBs that exactly match the same copper line spacing (a defect 128K RAM module for the Cambridge/Sinclair Z88 has the correct spacing of the contacts but that PCB is too thick) or are fully covered with copper, but thin PCBs are impossible to find. Starting from scratch however I could grind a PCB to the proper thickness. I also searched for flat cables with the proper connections, but no results either.
Looks like I found myself a nice weekend task.

Cello
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Re: Sharp PC-3000

Post by Cello » Thu Nov 10, 2016 11:05 am

Turns out that plastic cards like credit cards have the proper thickness to create a DIY RS232 plug for the PC-3000.

Found this idea on a great page:
http://web.archive.org/web/201408211339 ... /index.htm
which was referenced in:
https://kogs-www.informatik.uni-hamburg ... 00046.html

Kyodai
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Re: Sharp PC-3000

Post by Kyodai » Thu Nov 10, 2016 9:35 pm

Hmmm, sounds like it's worth a try.

I got this silver epoxy or "conductive silver". In germany it's sold as "Silberleitlack" - i like this one since it's just one component.


Example:

http://www.ebay.de/itm/KEMO-L100-Silber ... SwnbZYGvvo


You can apply a pretty thick layer and then carefully grind it down with sanding paper to the perfect thickness easily since it's hard after just like 15-20 minutes. And the stuff is soft enough to just "cut out" unwanted areas (the space between the conductive lines) with a scalpel or thin blade. Plus if you make a mistake the silver epoxy makes connecting destroyed lines pretty easy. I often used it where a soldering iron would be to difficult because of the size, but once you get used to it it feels like cheating your soldering iron.

Cello
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Re: Sharp PC-3000

Post by Cello » Fri Nov 11, 2016 9:04 am

Thanks for the lead and the instructions.

Took a dive in my glue box and unearthed a small tube containing "Electrically conductive coating with solid silver".
Sounds like more or less the same stuff.
I'll keep you updated whether this magic substance does the trick.

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