When we've purchased Ross chips for Sparc 10 and 20 machines, the 
seller didn't know which machine we were going to install in.  PROMS were
provided with the chips, and they've worked in both 10 and 20 machines.
The advice is good, change the PROM, test, then change the chip.
-Brian
On May 30,  9:26am, Harald Barth wrote:
} Subject: Re: Ross question
} 
} > We do have a Sparc-20 at work with the Ross PROM upgrade... does
} > anyone know whether a copy of this PROM would work in the Sparc
} > 10??? Or do I have to locate a Sparc-10 version? 
} 
} I think so. I have exchanged PROMs between SS10s and SS20s and did not
} have a problem with it so far. A good test is to first change the PROM
} (with the SM41 module still in place), see if that works and then go for
} the upgrade. The PROM should allways manage older CPUs.
} 
} If nothing else helps I could fix a PROM for you that works for the
} Hypersparcs I have. I'll trade that for any N scale model railroad
} car by Microtrains or Roundhouse. So now you know that :-)
} 
} Harald.
} 
>-- End of excerpt from Harald Barth