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From: mjw@aluxp.UUCP (Michael Weber)
Newsgroups: comp.sys.cbm
Subject: 1581 Floppy(?) Disk Drive Problem
Message-ID: <937@aluxp.UUCP>
Date: Sun, 22-Nov-87 04:01:24 EST
Article-I.D.: aluxp.937
Posted: Sun Nov 22 04:01:24 1987
Date-Received: Tue, 24-Nov-87 06:37:27 EST
Distribution: na
Organization: AT&T Bell Laboratories, Cedar Crest
Lines: 63
Keywords: 1581 C128 Commodore

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
particular, it looks as though any files written past track 40 were
completely corrupt!  Further investigation on one of the Q-Link discussion
areas showed that others have also encountered problems with this drive but
I could find no official or unofficial comments from CBM in reply.

One person mentioned that a service technician in his area had bought a
1581 and proceeded to replaced each IC in the drive to isolate the problem.
In his particular case, it was the WD1770 drive controller at fault.

Also mentioned was that Commodore will issue a bulletin in the (near?)
future describing the problem and its solution/resolution to all
authorized service centers.

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.  Please note that I
am only repeating the messages I encountered on Q-Link, they are in no
way supported or recommended by myself and definitely did not come from
CBM!

I've only used three disks in this drive to date and the only one that
had enough data written to it to pass track 40 (there are 80 total tracks)
ended up trashed.  With this kind of track record, I'm wondering if I will
ever be able to trust using this drive for anything more than a paper
weight?

Statistics on my 1581 (obtained using X-ray glasses, of course!  I'm hoping
something official happens before the remaining 60 of the original 90 days
expire):

	Serial number:  JA1 011854  (Does this mean over 10K produced?)
	Drive Controller:  WDC '82
			   WD1770-PH
			   00-02 8644
	DOS ROM:  318054-01 (EPROM)
	Disks used: SONY MFD-2DD

Does anyone from CBM care to comment (Fred, Carolyn)?  Given that it
appears my drive was not an 'early production' unit, and that all produced
before it may have the same problems, is Commodore stalling for time to
allow warrantees to expire?  I thought I was purchasing a reliable, high
density disk drive (with over a year of development inside CBM it should
be!).  Even with all the (now) know bugs in the 1541 and 1571 drives, I
personally NEVER lost a disk to these models! 

Let's clear the air on this device.  Is it a reliable, high quality design
or is there a large number of field returns currently being evaluated?
The drive is extremely quick and (in my opinion) should be the primary
drive of any C128 owner but until the data corruption question is resolved
I cannot recommend it to anyone.

BTW, before I'm flamed for not taking it to a repair center, I called one
up and they mentioned that unless I could duplicate the problem, they
would not look at it.  I've spent at least two hours trying to cause a
failure with no success (save with replace, anyone?).  Also, the corrupted
disk DID format correctly before and AFTER the problem.
-- 
Michael Weber					...!ihnp4!aluxp!mjw
AT&T Bell Laboratories
Allentown, Pennsylvania				(215) 770-2732