RE: PLA replacement for C64

From: didier derny <>
Date: Wed, 29 Apr 2015 21:32:16 +0200
Message-ID: <000301d082b3$33471e00$99d55a00$@org>
Strange I put a logic analyser, on the 6510...

01 on DATA
No NMI, No IRQ, rdy not used  r/w on read  (all the time)

The same signal on   PHI0, PHI2 and AEC..

I expected to see the 6510 trying to execute random code...

I retried during power up, apparently the 6510 is executing random data but
but r/w seems to be stuck to read.

The rams are cold (totally cold) other chips are warm but not very hot


-----Message d'origine-----
De :
[] De la part de
Envoyé : mercredi 29 avril 2015 18:41
À :
Objet : Re: PLA replacement for C64

On 2015-04-29 17:57, Clockmeister wrote:

>>>> I'm also thinking to the ram ship, but I think I would rather have 
>>>> a garbaged screen with a ram failure
>>> Not really. Only in some specific cases you get this kind of result.
>>> More RAM failures I had to repair manifested itself with no startup 
>>> screen than with garbled content.
> Sometimes the temperature of the RAM chip (or lack thereof) is a dead 
> giveaway especially if the problem is temperature sensitive. I've 
> diagnosed faulty RAM and ROM by touch alone.

That's especially true with the x464 chips. If they run /burning/ hot,
they're surely dead (and no startup guaranteed). It's less common with
x164 but happens sometimes too. As you mentioned - either way.


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Received on 2015-04-29 20:00:05

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