Re: CBM720 heads up

From: A. Fachat <afachat_at_gmx.de>
Date: Thu, 30 Oct 2014 07:18:31 +0100
Message-ID: <1495fb48738.279a.b4d1f2b66006003a6acd9b1a7b71c3b1@gmx.de>
Hi,

Am 30. Oktober 2014 01:32:18 schrieb Rhialto <rhialto@falu.nl>:

> On Wed 29 Oct 2014 at 23:48:35 +0100, Christian Dirks wrote:
> > I think this may just be a faulty video RAM ( 2k x 8 SRAM at U29) or the
> > 74LS157 at U15.
>
> If the RAM is faulty, then typing commands into the garbled area won't
> execute (properly). If the RAM is ok but the display is faulty, it will.
> Commands that you type are first stored in screen memory, until you hit
> return.

As the commands work and scrolling reveals the previously hidden screen 
content I suspect either the address multplexer or the CRTC itself. I'll 
check that today or tomorrow.

André
>
> -Olaf.
> --
> ___ Olaf 'Rhialto' Seibert  -- The Doctor: No, 'eureka' is Greek for
> \X/ rhialto/at/xs4all.nl    -- 'this bath is too hot.'



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