RCM - RETRO COMPUTER MUSEUM

GENERAL => FOR SALE / WANTED => Topic started by: Phu on January 27, 2011, 01:56:28 PM

Title: For sale (conditionally): Acorn Atom Colour Cards
Post by: Phu on January 27, 2011, 01:56:28 PM
I have put together the design for the Atom Colour Card (adds colour composite video output and RGB output to the otherwise monochrome Acorn Atom) and have this ready to send for PCB fabrication.

I'd like to build at least one for RCM's Atom, but it will stab a hole in my finances to get just one board made. So for this to be a realistic endeavour, I'd need at least 5, preferably 10 orders paid up front.

If your're interested in these boards, the cost will be £35 per board and includes shiny new PCB, new components and a composite video connector. Add £3 for a BBC Micro-style RGB socket connection.

Any interest?

-- Richard
Title: Re: For sale (conditionally): Acorn Atom Colour Cards
Post by: Panther on January 27, 2011, 04:28:41 PM
I'd love one, just not at the moment, as the finances are stretched to say the very least  :'(
Title: Re: For sale (conditionally): Acorn Atom Colour Cards
Post by: questor on January 27, 2011, 08:42:23 PM
I need to get an Atom first :-)
Title: Re: For sale (conditionally): Acorn Atom Colour Cards
Post by: IanS on January 27, 2011, 11:10:42 PM
Any interest?
Put me down for one, maybe two.

Are you going to publish your design?
Title: Re: For sale (conditionally): Acorn Atom Colour Cards
Post by: Phu on January 27, 2011, 11:30:42 PM
Its the same circuit as the original Atom Colour card, its just that they are so rare they are a bit hard to get a hold of :)

Once you have the board, all the components are still off the shelf, with the exception of the 6847 which you get from the Atom itself anyway.

-- Richard
Title: Re: For sale (conditionally): Acorn Atom Colour Cards
Post by: IanS on January 28, 2011, 12:10:31 AM
Its the same circuit as the original Atom Colour card, its just that they are so rare they are a bit hard to get a hold of :)
So this - http://www.stairwaytohell.com/temporary/atom_pcb_atomcolourboard.gif
Any pics of PCB design, does it match the original - http://www.xs4all.nl/~fjkraan/comp/atom/colourCard600x369.jpg ?

Title: Re: For sale (conditionally): Acorn Atom Colour Cards
Post by: Phu on January 28, 2011, 08:49:00 AM
Aye, the same circuit. As I say, its a bit difficult to get hold of, hence the DIY approach...

The circuit layout is largely the same. A few bits are in exactly the same place, but I've tried to keep it close.

No pics yet, I haven't had the board made (need money). But (if and) when I get them done, I'll be happy to post pics of a blank board and a populated board for your delight.

-- Richard
Title: Re: For sale (conditionally): Acorn Atom Colour Cards
Post by: IanS on January 28, 2011, 08:43:17 PM
Any pics of the board layout (from pcb design package)?
Title: Re: For sale (conditionally): Acorn Atom Colour Cards
Post by: centrespot on August 29, 2011, 09:47:27 PM
Did you take this any further?
Title: Re: For sale (conditionally): Acorn Atom Colour Cards
Post by: Phu on August 30, 2011, 09:18:46 AM
Unfortunately I didn't get enough interest to warrant having the complicated double-side board manufactured (trying to home etch them would be a right pain).

However, I believe Prime has these on his to-make list, so you might want to ask him if he has any.

-- Richard
Title: Re: For sale (conditionally): Acorn Atom Colour Cards
Post by: Prime on August 30, 2011, 10:40:13 AM
However, I believe Prime has these on his to-make list, so you might want to ask him if he has any.

I have a couour card designed and the first batch where built and have all been taken, I'm going to be producing another batch at some point in the near future, but am trying to sort out a couple of the little niggles with the first version before getting some more made.

Oh, and my colour card is SCART RGB only (0.7v) and not TTL, and does NOT change the scanrate from 60Hz to 50Hz, if you can live with these then you should be fine.

Cheers.

Phill.
Title: Re: For sale (conditionally): Acorn Atom Colour Cards
Post by: Phu on August 30, 2011, 11:52:23 AM
Phill,

I've still got my design on file, designed from the original colour card schematics with the RGB and composite video out. I can provide you with gerber and drill exports if you think it might be worth your while. I can also furnish you with some design screenshots and a 3D simulation so you can size it up.

Its designed to take up the same space as the original card and use the same 6847 replacing mechanism.

-- Richard
Title: Re: For sale (conditionally): Acorn Atom Colour Cards
Post by: centrespot on September 02, 2011, 09:30:05 PM
Richard,

I would be interested in receiving your design schematics etc. and investigating this further.

Frank
Title: Re: For sale (conditionally): Acorn Atom Colour Cards
Post by: Prime on September 04, 2011, 12:48:00 AM
I initaially tried building a copy of the YUV->RGB portion of the Acorn card and found it to be hard to adjust to get propper colour and had lots of descrete components.

Having since had a play with a real Acorn colour card I found that this also had the same problem, also the 60Hz->50Hz circuitry has the undesired effect of introducing a big block of white lines
at the bottom of the display area in colour graphics mode.

This is why I designed my own colour card which is based on a single surface mount chip, and also has the advantage of replacing the 12 2114s with a single 8K chip (note you can use a 16K or 32K
but only 8k is mapped, though I do bring the additional address lines to a header).

Cheers,

Phill.