[Coco] New Coco3 owner

Bob Devries devries.bob at gmail.com
Sat Aug 5 01:28:18 EDT 2006

PAL Coco3 should have a connector which looks the same as the video and 
audio connector, coming out in a hole marked RF OUT. There should also be a 
channel switch
These comments apply to the Australian PAL Coco3. Other's may be different.

I have seen these pulled out with rough treatment of the coco.

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: "Gene Heskett" <gene.heskett at verizon.net>
To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
Sent: Saturday, August 05, 2006 3:07 PM
Subject: Re: [Coco] New Coco3 owner

> On Saturday 05 August 2006 00:47, Joel Ewy wrote:
>>Mark McDougall wrote:
>>> Hi all,
>>> Having at one time owned an original silver Coco 1 during its hey-day,
>>> I've
>>> been a lurker on this group for about 2 years now.
>>> ...
>>> More recently I've become more interested in the Coco again,
>>> particularly since I started my FPGA emulation based on John Kent's
>>> CPU09 core. I've even
>>> submitted an article which should appear in the next CocoNutz eZine!
>>    I've been itching to get into FPGA computing as well, but haven't
>>managed to save up my pennies yet.  The possibilities are endless.  If
>>you had a system with a couple of FPGAs you could implement all kinds of
>>hardware and even special purpose processing right there on the chip.
>>With a 6809-ish CPU running at 12MHz, plus the capability to do things
>>like MP3 or JPEG encoding and decoding in hardware you have the best of
>>both worlds -- the simplicity of a CoCo-like system coupled with more
>>modern performance.  With modern FPGAs you can (or so I read) change the
>>logic functions as fast as you can write SRAM.
>>> ...o my utter delight I was offered the chance to give a PAL 128K
>>> Coco3 a new home - which I picked up yesterday afternoon about 2 hours
>>> drive
>>> away from where I live. It is in pristine condition and never been
>>> opened (until last night). Attached was a Tandy FD-500 disk controller.
>>> ...
>>> A few questions tho'...
>>> It doesn't appear to have an RF connector in the back, despite the
>>> existence
>>> of the metal can around what would/should be the RF modulator and the
>>> channel switch. Should it have one? Has someone pushed too hard and
>>> snapped
>>> off the connector and pushed it into the can?
>>    I've never had my hands on a PAL model, but the NTSC CoCo 3 most
>>definitely has a connector for the RF modulated output.  On the NTSC
>>model it's an RCA jack.
> Humm, maybe pal models have a scart jack?  Never saw one myself though.
>>> What sort of quality should I expect from the composite output?
>>> Admittedly,
>>> I've become used to seeing the output from MESS and my FPGA board
>>> (VGA) but
>>> I didn't expect washed-out colours and fuzzy text.
>>    Composite out on the ones I have is marginal.  Games are generally
>>fine.  32- and 40-column text are quite readable.  80-column text is
>>pretty blurry.  You can make out the words, but I wouldn't try writing a
>>novel without an RGB monitor.  In my experience the colors haven't been
>>washed out.  That might be a monitor issue.  Essentially I would use a
>>composite monitor or TV for games and similar things, or for programs
>>designed for the 32-column screen on the CoCo 1 or 2, but for anything
>>involving 80-column text, such as word processing, programming, et
>>cetera, I would use an RGB monitor.
>>> BTW I've since learned that the FD-500 requires a 12V supply and hence
>>> requires a multi-pak on the Coco 3.
> Which I'm not sure I understand the exact reason that so-called 12 volt
> line was left out of the coco3.  The official reasons was that the power
> supply was approaching meltdown in the coco3.  The rs232 pack derives its
> +-12 volts from an internal switching supply running off the 5 volt line
> obtained from the coco3, and thats a much much heavier load.  It was
> usually made by Aztec, and which I usually disconnect and bypass as mine
> runs in a multipack anyway.  I've also had them go up in smoke!
> But, the current draw needed by the 26-3022 from the 12 volt line is
> miniscule, ISTR according to ohms law it's a fraction over 1 milliamp.  So
> it could be restored just for that use with a relatively simple jumper in
> the coco3, getting around 8-9 volts somewhat noisey voltage to the
> 26-3022.  If thats not enough, a slight readjustment of the calibration
> pot should bring it into range.
> As the current draw is so low, I think rather than grabbing the 8 or 9
> volts from the collector of the 5volt pass transistor, I think I'd add a
> smallish diode right off the transformer, and another filter capacitor,
> maybe 47uf by 16 volts, thereby getting a much cleaner voltage. The ac
> ripple at the collector of the pass transistor can be a couple of volts,
> potentially effecting the 26-3022 even if its readjusted.
>>> Anyway, it's quite exciting to have a *real* Coco in my collection
>>> now. At
>>> some stage I'll look into getting a compatible disk controller (are
>>> any 3rd
>>> party *floppy* controllers considered "better"?) and also a 6309 and
>>> SuperIDE controller (I need to see what all the fuss is about
>>> Nitros09)! Would also love to play Nickolas's Donut Dilemma and Pacman
>>> Tribute on it too!
>>> Regards,
>>Have fun with it!
> -- 
> Cheers, Gene
> People having trouble with vz bouncing email to me should add the word
> 'online' between the 'verizon', and the dot which bypasses vz's
> stupid bounce rules.  I do use spamassassin too. :-)
> Yahoo.com and AOL/TW attorneys please note, additions to the above
> message by Gene Heskett are:
> Copyright 2006 by Maurice Eugene Heskett, all rights reserved.
> -- 
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