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From: wjt@wp3b01.UUCP (Bill Taggart)
Newsgroups: comp.sys.cbm
Subject: Re: 1581 Floppy(?) Disk Drive Problem
Message-ID: <452@wp3b01.UUCP>
Date: Mon, 23-Nov-87 08:08:59 EST
Article-I.D.: wp3b01.452
Posted: Mon Nov 23 08:08:59 1987
Date-Received: Thu, 26-Nov-87 19:50:41 EST
References: <937@aluxp.UUCP>
Reply-To: wjt@wp3b01.UUCP (Bill Taggart)
Distribution: na
Organization: AT&T Communications
Lines: 42
Keywords: 1581 C128 Commodore
Summary: Replace WD1770 with WD1772

In article <937@aluxp.UUCP> mjw@aluxp.UUCP (Michael Weber) writes:
>Has anyone noticed any problems with thier 1581 "floppy" disk drive?  I've
>owned mine for about a month and found that it managed to trash a disk
>while I was using it during a heavy download session on Quantum Link.  In
> ...
>One message described that the WD1770 drive controller should be replaced
>with a WD1772 controller chip (a real pain, the 1770 is NOT socketed).
>A 47 ohm J1 jumper resistor would also be necessary.
>-- 
>Michael Weber					...!ihnp4!aluxp!mjw
>AT&T Bell Laboratories
>Allentown, Pennsylvania				(215) 770-2732

I had this same problem with my 1581, but it only really
manifested itself in the CP/M mode.  I could duplicate it in
the C128 mode by having one of the devices connected to the
serial port turned off.  Also in the C128 mode I had many
"DRIVE NOT READY" errors -- including right after successful
disk accesses.  I emailed my problem directly to Fred Bowen
at CBM and he was extremely helpful and responsive in narrowing
in on the cause of the problem.  I don't know if CBM has
issued an 'official' fix for the problem -- but I fixed it by
replacing the WD1770 with a WD1772 and adding a 47 ohm
resistor at J1 as described on QuantumLink.  The drive no
longer trashes the directory in the CP/M mode and the "DRIVE
NOT READY" errors are much less frequent -- although they
still occur if I have been using the drive constantly for more
than two or three hours.  After the 'fix' I have never lost
any data and find the drive to be reliable.

As an aside Michael, would you please email the name of the
repair shop in Allentown that said they might look at the
problem for my future reference.  I called all over New Jersey
and Eastern Pennsylvania looking for a repair shop that would
look at the problem -- they all refused, and some were quite
nasty about it.  That's why I elected to fix it myself -- it
took me less than an hour.

-- 

	Bill Taggart
	{uunet | ihnp4}!wp3b01!wjt