Re: Fix for flaky MS-SoftCard Z80 clones

[mh4@deichjugend.de]

On Nov 29, 11:23 pm, Tarkin <Tarkin...@gmail.com> wrote:
>
> The CPU mine came with is:
> Goldstar Z8400A PS
>
> Which I replaced with:
> Zilog Z84C0008PEC
>
> The system is far, far, _far_ more stable now.
> I don't know if it is the fact that it's a CMOS
> part, or if that the chip is faster, or both.
> In any event, it's a cheap fix with immediate,
> practical results.

Of course the old chip can have a defect (or some other glue
chip on the card) and I'm glad you got rid of your problem.

However, I'm thinking of two explanations for the old chip
to fail:
- oxydized pins that just needed better contact
  Did you try putting the old CPU back in? Perhaps several
  extractions/insertions are necessary?
- A CMOS part needs less power than a HMOS one. Perhaps you
  already maxed out your power supply (lots of card?) or the
  power supply is on its way out?
They do not need apply, though, just came to my mind because
I had similar problems once.

bye
Marcus