Re: ZIPGS 2-pin Crystal

[andrew.webber2@btinternet.com (Andrew Webber)]

Wayne Stewart <waynes@intergate.ca> wrote in message news:<3D05573B.D5BEB89E@intergate.ca>...
> Andrew Webber wrote:
> 
>  
> > I just snipped the crystal and put in a 32Mhz oscillator. All worked
> > ok :-).
> > 
> > I then put in a 40Mhz oscillator and the system did not start, just a
> > single character appear on screen. I still have to change the SRAMs so
> > I think thats the cause.
> > 
> > Does that sound right?
> 
> Yep, changing to faster SRAM should allow you to get up to around 12mhz.
> After that you may, depending on your luck have to change the 74F00 to a 
> 74HC00.
> 
> 	Wayne


Thought I would update you on my ZIPGS 1.01 upgrade...

I bought 4 converters for SRAM sockets to allow a set of skinny
cache/tag chips to go in (I am not keen to cut and resolder the
sockets). I purchased 4 x 15ns Cypress 32kx8 Cache Chips
(CY7C19915VC)from RS components in the UK (�1.19 each). The converter
sockets I had to sand down the edges to get them all to fit in. That
was fun (not).

Powered up my system (ROM01, Stock PSU, 1MB Ram, SCSI Card) and all
works fine as a 8/64 system with a 65c816-14 chip and a 32Mhz
oscillator.

I decided to put a 40Mhz Oscillator and the system will hang in after
a about 5 - 10 minutes on the Out of this world demo at the same
location. Any ideas why that is? I then tried the 50Mhz oscillator and
the system starts to put GS/OS then bombs out.


I moved the card to my Rom03(Vulcan 40, CCFA Card,5MB Ram) GS and all
seems to work fine (demo was running for over 2 Hours) with a 40Mhz
Oscillator.

I then decided to put a (Still ROM03) a 50Mhz Oscillator in and as
soon as I boot the system I get a Fatal 911 error. Any ideas if this
is ZIP related or Motherboard not being able to cope with the speed?
If i take the 50Mhz chip out and put in a 40Mhz it works. I have read
some posts that this could be the ADB port?

I appreciate your help

Andrew