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From: jboggs@inco.UUCP (John Boggs)
Newsgroups: comp.sys.ibm.pc
Subject: Installing 3.5" 1.44M floppy drive in XT clone.
Message-ID: <7946@inco.UUCP>
Date: 9 Apr 90 17:27:07 GMT
Organization: McDonnell Douglas Electronic Systems, McLean, VA
Lines: 33

Last week I bought a new floppy disk controller and a 3.5" 1.44Meg
drive for my XT clone.  The installation was fairly simple but I ran
into a problem.  The controller documentation (SYSGEN Omni-Bridge)
was excellent and provided a lot of info on drives in general but it
lacked one significant point.

When I installed the new drive, I wanted it to be the A: drive so I
removed my old A: drive, left the old B: drive in place, and installed
the new 1.44M drive as A:.  When I booted the system, the new A: worked
fine but the old B: kept giving me a "not ready" error.  The SYSGEN
manual talked about cable terminators (terminating resistors) and said
that, when mixing a 5.25 and 3.5 inch drives, the terminator should be
in the 5.25 no matter whether it is first or second on the controller
cable.

When I put the terminator in, neither drive worked.  After messing with 
different things and re-checking all jumper and switch settings I decided
to switch the drives around (let the 5.25" be A: and the 3.5" be B:).
When I did this, everything worked fine but only if I left the terminator
out completely.

Can anyone explain what was going on here.  It all works now, but I'd
like to understand it so I won't make the same mistake the next time.

Thanks,

JB

-- 
John Boggs

McDonnell Douglas Electronic Systems Company
McLean, Virginia, USA