[Coco] [Color Computer] CoCo 2 questions.

[Bob Devries]

If this coco2 has the sockets for two RAM chips, you can fit 2x 4464 chips
to make it 64K, if it isn't already at 64k.

If the coco2 is fitted with a daughter board with 8 chips on it, then 8x
4164 chips are needed to replace them, or, remoce the daughter board, and
use 2x 4464 chips instead.

Have you checked that all the chips are securely plugged into their sockets?

----- Original Message -----
From: "Phill Harvey-Smith" <dragon at aurigae.demon.co.uk>
To: <ColorComputer at yahoogroups.com>
Sent: Friday, May 13, 2005 3:55 AM
Subject: [Coco] [Color Computer] CoCo 2 questions.


> Hi,
>
> Just got myself a cheap, (£4.99) CoCo 2 off ebay, not working at the
> moment, but I intend to fix that :) I have a couple of questions :
>
> 1) It seems very different from the CoCo 1, much more compact, and seems
>   to have some different chips. Does anyone know where I can get a
> circuit sheet for this, I have the CoCo 1 tech ref, but this seems to
> different.
>
> 2) There are a couple of chips with numbers I don't recognise they are :
>
> HD61J204P / TCC1000, a 28 pin chip on the bottom left of the board.
>
> SC7331P, a 40 pin chip in the top middle of the board, next to the 6821,
> this seems to be connected to the keyboard, so I assume it's a PIA, but
> that's a number I don't recognise.
>
> 3) There seem to be some wire links to select between 16K and 64K rams,
> assuming that I can get some 64K, what type does it need (41464s at a
> guess) ?
>
> Also the machine seems to have a 74LS785, rather than a 74LS783, I have
> tested this in my Dragon test board and it works ok, but wondered what
> the difference was ?
>
> Thanks.
>
> Phill.
>
>
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