Re: TransWarp GS ROM question

[spec@vax2.concordia.ca (Mitchell Spector)]

In article supertimer@aol.com (Supertimer) writes...

>spec@vax2.concordia.ca (Mitchell Spector) wrote:
> 
>>    I'm about to acquire a ROM chip for my currently non-functional
>>TransWarp GS board, incase I decide to repair and upgrade it some-
>>time in the near future. The person with the 1.5 ROM claims unlike
>>his 1.8 ROM, the board gets unstable above 10 MHz and causes problems 
>>with ProTERM 3.1 at 7.8 MHz and above (apparently the 1.8 does not).
> 
>This person is absolutely wrong.  I and at least two other csa2
>readers have NO such problems with 12.5Mhz TWGS units
>possessing 1.5 ROMs.

    That's certainly welcome news to hear.

>Most likely, your friend had bad static RAM chips.  He or she
>probably upgraded to a 32k cache at the same time as the
>1.8 ROM upgrade.  It is not the ROM's fault.

    That was my first guess. The only other possibility is that
the EPROM's data has been corrupted in some way, but hopefully
that won't turn out to be the case.

    Incidentally, are the SRAM's on a typical 8K daughterboard
fast enough to support 10, 12 or 15 MHz?

>By the way, I seriously suggest that before you give your
>2 TWGS units the 9th degree that you try replacing the
>CPU chip.  In older TWGS units, the 65C816 were very
>flaky because the old design was pushed to the limit.  You
>keep saying how your Zip GS is better and all that.  Stop to
>think about what is logically the most different...the Zip GS
>has a redesigned 65C816.

    Not a bad idea, how much does a 65C816-14 currently cost?
(Is Alltech and WDC still the only source?)

Mitchell Spector
spec@vax2.concordia.ca