Re: strange 2001N fault

From: Gerrit Heitsch <*gerrit_at_laosinh.s.bawue.de*> Date: Tue, 20 Feb 2018 17:34:22 +0100 Message-ID: <c545e752-ed83-513f-0319-0201e49b4330@laosinh.s.bawue.de> · gerrit_at_laosinh.s.bawue.de

On 02/20/2018 11:53 AM, Francesco Messineo wrote:
> Hi all,
> in case someone doesn't read vcfed forums, my 3032 developed a strange fault:
> 
> http://www.vcfed.org/forum/showthread.php?62202-3032-(2001N)-strange-fault
> 
> The thread link is just to recap what I've found and what I did, so I
> don't have to type all again here ;-)
> Ideas welcome, I'm just scratching my head. This is probably where a
> logic analyzer is needed badly.
> It seems to me there're unintended writes on some ram locations (not
> so random, address wise) and it makes me think about VSP crashes on
> C64.
> Any idea where to look for a fault?

Address multiplexer? I think on those boards they used the 74LS153 which 
contains two 4-to-1 multiplexer. Also check their control circuits.

  Gerrit

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