[Coco] Coco2 video

Bill Pierce ooogalapasooo at aol.com
Fri Jul 29 14:33:11 EDT 2016

The Coco 2s with the motherboard model number ending in "2B" are the models with the true lowercase. They were the last Coco 2s built before the release of the Coco 3.
The lowercase was never supported by RSDOS, even on the Coco 3 which "featured" true lowercase, though OS9 (L1 & L2) supported lowercase on all Cocos, even as "reverse text" on the originals.
There were several "fixes" that allowed true lowercase in RSDOS (ADOS comes to mind), as well as a hardware fix to make it permanent, but very few programs ever used it due to Tandy's "backwards compatability" policy.
The older Cocos "could" be refitted with "6847T1" chip, but it's not an easy task. The chips have different pinouts and things have to be added to make it work. There was 2 Rainbow articles on the 6847T1 chip & mod.
Rainbow Sep '86 "Turn Of The Screw" - "A Look At The Coco 2B" - page 125
Rainbow Oct '86 "Turn Of The Screw" - "Hardware Fix For The VDG" - page 161



Bill Pierce
"Charlie stole the handle, and the train it won't stop going, no way to slow down!" - Ian Anderson - Jethro Tull


My Music from the Tandy/Radio Shack Color Computer 2 & 3
Co-Contributor, Co-Editor for CocoPedia
Global Moderator for TRS-80/Tandy Color Computer Forums

E-Mail: ooogalapasooo at aol.com



-----Original Message-----
From: Zippster <zippster278 at gmail.com>
To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
Sent: Fri, Jul 29, 2016 2:10 pm
Subject: Re: [Coco] Coco2 video

Most of them will have the standard MC6847, which won’t support lowercase.It’s possible to add an external character ROM board to upgrade those, with something like this… <https://sites.google.com/site/thezippsterzone/mc6847-vdg-projects/mc6847-external-character-rom/a-final-cpld-version-of-the-mc6847-external-rom <https://sites.google.com/site/thezippsterzone/mc6847-vdg-projects/mc6847-external-character-rom/a-final-cpld-version-of-the-mc6847-external-rom>>However, most software will expect no lowercase to be available on the system.- Ed> On Jul 29, 2016, at 11:03 AM, RJ Lilko <rjlilko at randing.ca> wrote:> > I am looking to purchase a coco2 from eBay as there are a lot of them. But my reading indicates that early models didn't have the video chip to produce lower case, right? Were the early models upgradable? I assume I have to be careful in making sure what product code version I am getting, right?> > Sent from my iPad> > -- > Coco mailing list> Coco at maltedmedia.com> https://pairlist5.pair.net/mailman/listinfo/coco-- Coco mailing listCoco at maltedmedia.comhttps://pairlist5.pair.net/mailman/listinfo/coco

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