Re: Some II+ Questions. (ProDOS etc.)

["Tom Zuchowski" <tzuchow@attglobal.net>]

I don't have personal experience in doing a 6502/65C02 swap, but I do
industrial digital electronics repair for a living and I have never heard of
a case where you could not swap the "standard" NMOS version of a VLSI chip
with the CMOS version. There are no doubt a few instances of such
compatibilities, but I assure you that they are very rare, and they will be
very narrow in their scope. On the whole, the biggest differences to the
user between NMOS and CMOS IC's is that the CMOS version consumes far less
power and it is generally able to utilize a larger scope of supply voltages.

I can't imagine ANY way in which a 65C02 could damage a II+ motherboard. As
for the ROMs/EPROMS, they are virtually 100% interchangeable electronically,
though the CMOS versions consume a LOT less power. The timing requirements
are a little different and the 65C02 may not work, but it can't possibly
damage the motherboard. Let's remember that any time you mess with a
motherboard you are running a risk of damage, especially on our old, old
Apple II stuff. I can probably come up with a half-dozen different things
that might have killed Cliff's II+, but I don't think it had anything to do
with electronic incompatibility with the 65C02.

Tom Zuchowski


"Stephen Shaw" <stephen@apple2.org.za> wrote in message
news:9h51ft$39s$1@venus.itns.co.za...
> Very doubtful that the 65C02 caused the II+ to die.
>
> On Fri, 08 Jun 2001 16:51:22 +1000, John L wrote:
>
> > On Thu, 07 Jun 2001 22:37:19 -0700, Cliff Allo <cliffallo@qwest.net>
> > wrote:
> >
> >>Because the 65C02 may have a different resistance or voltage
> >>requirement from the stock 6502, you risk burning your ROMs if you
> >>simply swap the CPUs. At least that's how I killed my ][+.
> >
> >
> > Can anyone here confirm or deny this ?
> >
> > I have a ][+ running with a  65c02 - no apparent problems.
>
> --
> The reason computer chips are so small is computers don't eat so much.