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Newsgroups: comp.sys.cbm
Subject: Re: 1571 troubles (fix!!!)
Message-ID: <1991Apr28.004652.503@vax1.mankato.msus.edu>
From: neusoft@vax1.mankato.msus.edu
Date: 28 Apr 91 00:46:51 -0600
References: <91115.174020PTS102@psuvm.psu.edu>
Organization: Mankato State University
Lines: 51

In article <91115.174020PTS102@psuvm.psu.edu>, PTS102@psuvm.psu.edu writes:
> My 1571's motor seems to be having trouble grabbing the disk- i.e. the
> motor spins but the disk doesn't.  I have to turn the handle VERY HARD
> to get the motor to grab, and as a result I cracked the handle off
> (there's a knob there now).  Also, at the beginning of a read or write,
> the LED sputters as though there's no disk in the drive, but 'catches'
> within a second or so.  I've tried cleaning the moving parts of the handle
> mechanism with limited results.


Hmmmm, this seems to be a very common problem.  Well, I have had the same
problem with the C128D's internal drive, but never thought much of it.  In
fact, I found it quite easy to fix.  The problem is that unlike the 1541 drive,
the 1571 is double sided (Gee mike, but what does that have to do with
anything?).  Well, instead of a second head in the 1541, the other side of the
disk rides on a small felt head to put presure on the read/write head allowing
it to read the disk.  When you close the door without a disk in the drive, no
problem...the head simply rests against this felt pad.  The 1571, on the other
hand, puts the second head in place of this felt pad.  If you were to close the
drive without a disk in it now, the two head will come incontact with each
other (not a good idea since the heads are very delicate).  Well, the way
Commodore chose to eliminate this problem was to simply not let the heads come
down all the way if a disk is not in the drive.

If you wish, take apart your 1571 and take a peak inside (note:  I am not
responsible for people destroying their drives (or themselves) out of their
own stupidity...so unplug the damn thing, and don't do nothing unless your
sure about yourself!!!).  Towards the back of the drive (on the left if you 
look from the front of the unit) is a small plate attached to the heads.  
Underneath the plate is a small lever.  The lever is spring loaded so that when
no disk is in the drive this lever will be underneath this plate.  Now, try to
close the drive.  The lever will prevent the plate from coming down all the
way, thus keeping the heads appart.  If you put a disk in the drive, the lever
should go all the way back, so that when the drive door is closed, the plate
(and the heads) will now come all the way down.  

Sometimes (or in the case of most people...most of the time), the lever does 
not go back all the way, and catches on the edge of this plate, preventhing 
the heads to close down on the disk.  A light tap on the disk, or pushing the 
disk in again after the drive is closed, clears the lever, letting the heads 
fall onto the disk (hence the click).  Well, I was able to fix my drive by
bending the lever up(?) slightly, letting the plate catch on the pointed part
of the lever, which will push the lever back as the drive door closes.  Be
carfull if you try this however...the first time I tried it, I let the heads
fall from the open position to the closed posision (which made a loud 'slap'),
and ruined both heads.  Luckily, I was still able to exchange the computer, so
it didn't cost me anything  :)

-Mike
neusoft@vax1.mankato.msus.edu