Newsgroups: comp.sys.3b1
Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!sci.ccny.cuny.edu!jeffrey
From: jeffrey@sci.ccny.cuny.edu (Jeffrey L Bromberger)
Subject: Re: Formatting blues
Message-ID: <1991Apr4.133755.5525@sci.ccny.cuny.edu>
Followup-To: comp.sys.3b1
Summary: I am using the 74s02
Keywords: format XT2190 hang
Organization: City College of New York - Science Computing Facility
References: <1991Apr1.023108.22419@sci.ccny.cuny.edu> <1991Apr2.155122.23817@sci.ccny.cuny.edu> <1991Apr3.021828.11340@ceilidh.beartrack.com>
Date: Thu, 4 Apr 91 13:37:55 GMT

In article <1991Apr3.021828.11340@ceilidh.beartrack.com> dnichols@ceilidh.beartrack.com (DoN Nichols) writes:
>	Replace the 74ls02 with a 74S02 or a 74F02 and your cable-length
>sensitivity will go away.  The 74ls02 is marginal, at best, when driving the
>data separator on the 3b1/7300.  With the 74ls02, I could see the pulses
>going INTO the chip with a logic probe, but not see them coming OUT of the
>chip to the data separator.  (One brand of 74ls02 from my stock gave LOTS of
>HDERR's, another very few, and the 74F02 or 74S02, none, even with nearly a
>foot of cable!)

Well, I did that.  Way back when.  It *is* running with the 74s02.  The
ls02 just didn't cut it.  But, even with the s02, the cable between
the motherboard and the expn board still made a difference.  Nearly 4
megs a day difference :-)

>	Do you have the enhanced diagnostics disk?  It should be able to
>format either drive, and anywhere up to the full size of the drive.  (I
>understand that the /etc/iv may be restricted in maximum size unless it is
>modified, but I have always used the diagnostics disk.)

I am using the new diagnostic disk to do the format.  As I said, the
drive works!  It only refuses to format on the machine with the
upgrade board.  It will format down to 67Mb on an old 7300, but that's
without either the 5.1 or 2010 parts.

What I've finally decided to do is to beat upon my stock machine, and
put in the DRUN and the p5.1 (from brian botton).  That will at least
get it to format.  Then the question comes down to this, how to
tighten up the icus board?  Would bypass caps make a whole lot of
difference?  Maybe shortening the ECO wires from the motherboard?

>	Good Luck

Thanks, I'ma gonna need it.  Especially once I dump my other 2
machines, leaving me only the ICUS upgraded one.  Let's hope I can
figure this one out before June - I have a new second drive coming
then.

j
-- 
Jeffrey L. Bromberger
System Operator---City College of New York---Science Computing Facility
jeffrey@sci.ccny.cuny.edu			jeffrey@ccnysci.BITNET
	Anywhere!{cmcl2,philabs,phri}!ccnysci!jeffrey