Re: Transwarp IIe revisited

[mdj <mdj.mdj@gmail.com>]

On Dec 8, 2:37 pm, Linards Ticmanis <ticma...@gmx.de> wrote:
> Michael J. Mahon wrote:
> >> I've not yet been able to get Ultima V to work correctly with the card,
> >> so I guess I'll try exchanging some RAMs. How fast do they have to be?
>
> > Look at the number(s) after the dash and you'll find the speed.
>
> They say -15, which I guess means 150ns. I swapped the chips with some
> of those on a "Slinky" card (also 256x1 at 150ns) and the problem got
> considerably worse, even though all involved chips passed both the
> Slinky's and the Transwarp's own self tests.
>
> Also, if the 65C02 runs at NTSC color carrier frequency as I assume, its
> phi2 lasts only about 140ns.
>
> I suspect that the 150ns RAM on the card was maybe not originally there,
> and that it is simply too slow.

FWIW, my card has 80ns RAM on it. I imagine someone has swapped the
RAM at some earlier point, 150 is way to slow

You can probably get by with 120ns, but with 80ns and even 60ns parts
commonly available, why risk it ?

Matt