[Coco] Coco 1 question
jmichea at cogeco.ca
Sun Nov 22 12:21:25 EST 2009
You may be right. I can't get this unit to turn on at all. It seems
completely dead. Oh well, I'll keep it for parts. I'm not a "techy" so I
can't fix it.
Thanks for your help everyone.
----- Original Message -----
From: "Bruce W. Calkins" <brucewcalkins at charter.net>
To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
Sent: Sunday, November 22, 2009 7:22 AM
Subject: Re: [Coco] Coco 1 question
> Jeremy Michea wrote:
> I picked up a Coco 1 and with manuals and 6 rompaks for $10 at a charity
> garage sale today and I looked at the model number on the back - 26-3004A.
> I can't find much info on this particular model. How much memory would
> this unit have and what's the difference between it and the 26-3004?
> The CoCo 1 was for the most part known by the board revision letter.
> There are a few "C" boards in the wild with the "D" board being the first
> in major production. "D" and earlier are more difficult to upgrade to 64k
> use what with trace cuts and adding jumpers. All that considered, I keep
> any unmodified "D" boards as is for the historical value.
> The "E" boards only need a couple jumpers added to make user of a spare
> gate on the 74LS02 for the upgrade to 64k. They are more common than the
> earlier boards.
> The last variant of CoCo 1 was the "F" or 285 boards. It did not have a
> letter after the board number but the board number ended in 285. It
> supported 64k with built in jumpers.
> As to the 26-3004A designation? That would most likely refer to the
> Extended Basic ROM in a later model CoCo 1. Without any other data I
> would guess it is the "F" or 285 board with Extended Color Basic.
> Powering it up, if it does not blow a capacitor or two will show on the
> boot screen the Basic ROM version and level. A PRINT MEM command will
> give the available RAM. You won't know unless you open the case, look and
> decipher the RAM markings or enter PRINT MEM. As Robert stated; "with 32K
> RAM you will get 22824." However I believe that would be for a system
> that has a Disk controller installed. Non disk systems should show around
> 12584 for a 16k system, or 28968 for a 32k system using Extended Color
> Basic. Color Basic only systems will show more available RAM and Disk
> Extended Color Basic used up another 6k.
> Also be aware that a few of the early "F" / 285 board units had a timing
> issue and would crash about the time they warmed up. There is a fix, but
> to the best of my knowledge it is out of stock. Someone else may have
> some data on that. I have one that I never did get fixed. I keep it for
> spare parts for my other "F" /285 board CoCo 1.
> Bruce W.
> Coco mailing list
> Coco at maltedmedia.com
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