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From: C506634@UMCVMB.MISSOURI.EDU (Eric Edwards)
Newsgroups: comp.sys.amiga.hardware
Subject: Flakey floppy
Summary: Is it the 8520?
Keywords: floppy, 8520, corrupted disks, Pioneer, Supra
Message-ID: <900829.161641.CDT.C506634@UMCVMB.MISSOURI.EDU>
Date: 29 Aug 90 21:16:41 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Lines: 56

WARNING:  Long, drawn out, hardware problem follows.

I'm having problems with my external floppy drives that I think is caused
by a flakey 8520.

I started out with with a pioneer external drive.  I've always had problems
writing disks formated from other drives.  It would also send out eroneous
diskchange signals (that what it looked like at least) ocasionally.  However,
it would write it's own disks just fine.  The local repair shop checked it
out and the heads are inline and the speed is in spec.

Recently, the Pioneer drive started to corrupt it's own disks.  I assumed
the fault was with the drive so I bought a SupaDrive.  I set up all
possible combinations.

Pioneer df1:  Supra df2:
        Pioneer Reads and writes it's own disk just fine.
                Corrupts disks created with internal floppy
                Diskchange problem SEEMS to be gone.
        Supra   Corrupts all disks (eventually)
                Powering down and backup seems to help but it still
                corrupts the disk.

Pioneer df2:  Supra df1:
        Pioneer Sends out eroneous diskchange signals every 20 seconds or
                so.
        Supra   Not thouroughly tested.

Pioneer df1:  no df2:
        Pioneer just like before.  Corrupts all disks.  Occasional disk
        change.

Supra   df1:  no df2:
        Just like Pioneer.  The supra never sends eroneous disk changes.

In all cases diskcopying will work whether or not other operations work.

In the same time frame that I discovered the problem of the Pioneer
corrupting all disks, the joystick port has ceased to function properly.
There is a constant "turn right" signal.  Joystick works fine in mouse
port.

Given that the 8520's handle both the floppy drives and the joystick ports.
And 8520's are notorious for being the root of joystick problems.
And both problems have occured in a time frame close enough to be the same.
I tenativly point my finger at one of the 8520's.  BUT I've never heard of
a chip problem causing disk problems.

Can someone verify if this is plausible or maybe suggest another
explanation?

Thanks.

Eric Edwards  c506634 @   : "See computer history first hand. Dial up your   :
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