[comp.sys.ibm.pc.hardware] My 386 hangs at 25MHz, but not at 20MHz

evil@arcturus.uucp (Wade Guthrie) (08/09/90)

I just purchased a 386 (purchased w/ hercules-compatible graphics,
a microsoft mouse, a single floppy, but no hard disk) and, separately,
an Adaptec 1542B SCSI controller (which controls the floppy and. . .) 
and, from a third party, a Seagate ST1096N hard disk drive.  

I can boot my machine at 20MHz and run Windows 3.0 and Word For 
Windows (I still haven't bought my C compiler and devlopment kit) 
all day long; no problem.  If I boot at 25MHz, the system hangs.  
Not always at the same point, mind you, (it seems to hang in the 
middle of a hard or floppy disk access -- disk access light on but 
nobody home -- but not always) it usually doesn't get past the 
"white screen" on windows, but the other day it got into Word 
before it hung.  Last night, it hung on boot-up with a "cannot find
IBMBIO.COM" message.  I couldn't install Windows at 25MHz, I had
to do it at 20.  Figuring that it might be a Windows thing, I borrowed
a C compiler and tried to load it at 25MHz; it got about five disks
in before it stopped.

I have tried the ASPI4DOS driver -- this don't work.  I've tried
all three windows modes (the "best" being 386 Enhanced); they all
react the same way.  I've read the readme file for windows and
alternately tried adding and deleting the flags in the config.sys
as well as the line recommended in the .INI file.  Whimper.  I
even tried making sure that the IO address space wasn't multiplexed
between two devices; nada.

Please Help.  Thanks.
-- 
Wade Guthrie (evil@arcturus.UUCP)    | "He gasped in terror at what sounded
Rockwell International; Anaheim, CA  | like a man trying to gargle while
My opinions, not my employer's.      | fighting off a pack of wolves"
                                     |                Hitchhiker's Guide

ruhtra@turing.toronto.edu (Arthur Tateishi) (08/11/90)

In article <1990Aug9.163309.16138@arcturus.uucp>, evil@arcturus.uucp (Wade Guthrie) writes:
>I just purchased a 386 (purchased w/ hercules-compatible graphics,
>a microsoft mouse, a single floppy, but no hard disk) and, separately,
>an Adaptec 1542B SCSI controller (which controls the floppy and. . .) 
>and, from a third party, a Seagate ST1096N hard disk drive.  
>
>I can boot my machine at 20MHz and run Windows 3.0 and Word For 
>Windows (I still haven't bought my C compiler and devlopment kit) 
>all day long; no problem.  If I boot at 25MHz, the system hangs.  
>Not always at the same point, mind you, (it seems to hang in the 
>middle of a hard or floppy disk access -- disk access light on but 
>nobody home -- but not always) it usually doesn't get past the 
>"white screen" on windows, but the other day it got into Word 
>before it hung.  

My guess at the problem would be that the busclock setting is too high.
The setup for AMI BIOS lets you decide between different bus-clock 
speeds and I wonder if changing the setup from CLKIN/2 to CLKIN/3, or
whatever, would solve the problem. CLK/2 would run the bus at 10MHz or
12.5 MHz which I feel may be just enough of a difference to cause
intermittent problems with slow things like drives.

-- 
``Sex and drugs? They're nothing compared with a good proof!''
                                - A Cambridge student  (r.h.f)
Arthur Tateishi                 g9ruhtra@zero.cdf.utoronto.edu

davidsen@crdgw1.crd.ge.com (William E. Davidsen Jr) (08/14/90)

In article <1990Aug9.163309.16138@arcturus.uucp> evil@arcturus.uucp (Wade Guthrie) writes:

| I can boot my machine at 20MHz and run Windows 3.0 and Word For 
| Windows (I still haven't bought my C compiler and devlopment kit) 
| all day long; no problem.  If I boot at 25MHz, the system hangs.  

  I suspect a bus speed problem. Try slowing it down or adding a wait
state. Hopefully you can change the speed of the bus separately.
-- 
	- bill davidsen (davidsen@crdgw1.crd.ge.com)
	GE Corp. R&D Center; Box 8, KW-C206; Schenectady NY 12345