Problem with 9836C floppy drive--resolved, but I'm not sure why!

From: Stan <swperk_at_earthlink.net>
Date: Sat Jan 25 18:49:00 2003

Hi Tony and everyone,

Thanks for the suggestions. All of the floppies that I substituted looked
absolutely identical to the one that wasn't working.

The last thing that I did was to try another floppy drive data cable (it's
the standard PC-style dual floppy cable with the 34-pin IDC connector on the
controller end and the card edge connector on the other end). When I simply
replaced the original cable on the left-hand drive with the new one, the
problem remained. When I swapped the cables to each drive (right going to
left and left going to right), it worked perfectly! I assume that there must
be some sort of drive select or other difference between the two floppy
drives, but why the right one works in either location, and the left one
works only as the primary (right-hand) drive is beyond me.

After I convinced myself that everything was now okay, I physically
interchanged the floppies (left to right and right to left) and took the
opportunity to examine them very carefully to look for differences. I saw
none. Even the date codes were identical! I'm not saying that there aren't
any differences--in fact, there must be--but there wasn't anything obvious
to me.

The only difference with the 9836C that I notice now (besides the obvious
lack of an error message at startup) is that the LED on the floppy
controller board labeled "TR00" (those are zeroes) is no longer illuminated
after the POST. I assume that is a Track 0 seek failure indicator, but I'm
just speculating.

Whatever the case, I'm delighted that it's fixed! Thanks to everyone for
their help and suggestions!

Regards,
Stan

From: ard_at_p850ug1.demon.co.uk (Tony Duell)
Subject: Re: Problem with 9836C floppy drive
To: cctalk_at_classiccmp.org
Date: Fri, 24 Jan 2003 19:06:48 +0000 (GMT)
Reply-To: cctalk_at_classiccmp.org

> series of high and low pitched beeps (low, low, high, low, high, high,
low).

I assume that's some kind of error code, which would be useful if the
video side was malfunctioning. Anyone have a table of them?

> After that, it is able to load an OS (HP BASIC) and run fine, with the
> exception that the left-hand floppy drive is inaccessible.
>
> I've taken a known good floppy drive, floppy controller, and even the CPU

I assume you checked that the replacement drive was configured the same
way (link settings, termination resistor pack) as the old one?

What about the cables to this drive? Have you checked it's getting power
(IIRC there's a conventional 4 pin power connector in there). Have you
tested/swapped the data cable?

-tony
Received on Sat Jan 25 2003 - 18:49:00 GMT

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