[Coco] My coco3 gallery

[Bob Devries]

My Case Changer PCB has the following chips:

74LS161, 74LS245, 74LS86, 74LS10, MBM2716, and of course, the MC6847.

Besides that, there's 2 resistors (pull-up 10K), 1 10uF tantalum capacitor, 
1 1uF cap, and 3 2-position links (which can be wired out to switches).


--
Regards, Bob Devries, Dalby, Queensland, Australia

Isaiah 50:4 The sovereign Lord has given me
the capacity to be his spokesman,
so that I know how to help the weary.

website: http://www.home.gil.com.au/~bdevasl
my blog: http://bdevries.invigorated.org/

----- Original Message ----- 
From: "Phill Harvey-Smith" <afra at aurigae.demon.co.uk>
To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
Sent: Saturday, August 26, 2006 7:51 AM
Subject: Re: [Coco] My coco3 gallery


> Bob Devries wrote:
>> Phill Harvey-Smith said:
>>
>>> That's cool...guess I should post some piccies of my CoCos/Dragons at 
>>> some point.....
>>
>> Please do. I'm always interested in other computer systems, especially 
>> those which were very uncommon, like the Dragon. I don't think the Dragon 
>> was ever sold in Australia.
>
> Yeah I think they where only sold in the UK, Spain, once DragonData where 
> sold to Eurohard, and under license by Tano in the USA. If you want to see 
> some piccies of some of the rarer Dragons, then check out 
> http://www.dragondata.co.uk
>
>>> You don't happen to have the schematic for the lower case mod do you 
>>> (and a dump of the character rom), I'd like to have a go at making one 
>>> of those sometime.
>>
>> I'll see what I can do on that score. I don't have a schematic, but it 
>> shouldn't be too hard to produce from the PCB.
>
> No, having looked at the data sheet for the 6847, I think I could possibly 
> work most of it out, I can see several chips apart from the 6847, the 
> character ROM, a LS161, which seems to be used to scan each line of each 
> character, an LS245 buffer, a LS86 quad XOR gate, which I assume turns off 
> the extra circuitry when in non-text modes, and another
> chip which I cannot see the part no on :)
>
>> I can dump the contents of the character ROM (if I don't already have it) 
>> on my EPROM burner.
>
> That would be cool, If you can take a good picture from directly above and 
> directly below the board I can prolly trace tracks from there :)
>
>> The PCB sits in the socket of the 6847 VDG chip, and the chip is plugged 
>> into the PCB.
>
> Yeah I have produced several boards using this method, for adding extra 
> stuff (especially in the Dragon Alpha/Professional clone).
>
> Cheers.
>
> Phill.
>
> -- 
> Phill Harvey-Smith, Programmer, Hardware hacker, and general eccentric !
>
> "You can twist perceptions, but reality won't budge" -- Rush.
>
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