[comp.sys.xerox] Proble w. Dandelion

chris2@cosmo.UUCP (Christoph Heeb) (08/28/88)

Is there anyone who's able to give me some assistance to the follow-
ing problem.
My problem is on a Dandelion which we decided to run as a server.
The problem occurs at the moment I try to format or I try to do a 
new disk checck out. To this moment the system detects a 'microcode-
fatal-error page 112 cyl. 0.
The error vanishes if I use a HSIO-PWA with a newe revision-level.
Then it's possible to format the disk; no problems.
The old HSIO I first used was from a 29Mb Server which I now use,
after some hardware changes, as a 42Mb Server!
So my question is:
Does anyone know about such porblems and the second, is it pos-
sible to do some hardware revisions on the HSIO by myself, to use 
the old HSIO with the 42Mb Rigid-Disk?
The not running HSIO-PWA is 140S24754  /091981
The running is             :140S24757  /110584
Perhaps a ..755 would also work the right way, I don't know!
Thanks for any assistance and help.
Regards chris

darrelj@SM.UNISYS.COM (Darrel VanBuer) (08/30/88)

The problem you are running up against is almost certainly due to the different
data clock rate used by the two disk drives.  The 29 MB disk uses a slower
data rate plus a 6% missing sector to hide timing marks.  To change a it
may require some combination of new crystals, retuned PLL, and new ROMs.
I expect even Xerox would have a hard time changing it at this late date.