Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!mcsun!ukc!dcl-cs!gdt!exspes From: exspes@gdr.bath.ac.uk (P E Smee) Newsgroups: comp.sys.atari.st Subject: Re: Wanted: Chinon Floppy Drive Horror Stories Message-ID: <1990Aug29.100251.11916@gdr.bath.ac.uk> Date: 29 Aug 90 10:02:51 GMT References: Reply-To: P.Smee@bristol.ac.uk (Paul Smee) Distribution: comp Organization: University of Bristol c/o University of Bath Lines: 56 In article ralph@laas.fr writes: >Some time back there were numerous postings concerning the (in?)famous >Chinon floppy drive. As I remember, many people had problems with its >media change detection. > >What were the conlusions of those postings? My new Mega 4 ST has a >Chinon Rev B F-354 EAA drive in it. It has been sent back to the >dealer to fix the `media change problem'. I'm curious as to what >official solutions that were made available. I worked up a fix for the problem mechs at the time when Cumana was using them. I wrote to Cumana describing the problem and my fix; I got a letter back saying they'd discussed it with Chinon and my fix was 'suitable and appropriate'. Don't know if the publicised it. IF you are comfortable with taking your ST apart, what you do is: Remove the drive mech. Looking into it, you'll see there are 2 little pin switches, one of which is located where the write-protect hole in the disk is, and a second right next to it. The first is the write-protect sense switch; the second is a 'disk present' switch. The internal circuitry of the Chinon drive means that the WP switch state doesn't get sent to the ST unless the disk present switch is closed. The 'fix' is to make the disk-present switch be permanently closed. The way to do this is to solder a small jumper wire across its terminals on the bottom of the drives PC board. In my drive, both switches were in a single unit, but it was obvious which set of terminals went to which side. NOTE --- I don't know if all Chinon drives with the problem are constructed the same way, so neither I nor anyone else I've mentioned can be held responsible if you try this and it breaks things. All I will commit to is that it worked fine for me... I've fixed 2 Chinon mechs that way. (It's a good way to get a reliable CHEAP mech -- there are a lot of them flying around, presumably because people have discovered they don't work on STs. Unless you perform the trivial modification.) ALSO NOTE -- Not all Chinon drives have the problem. In particular, Cumana claimed that they were going to switch to a different model of Chinon mech which worked properly in this regard. >Suggestions are also appreciated. Is there a good test program for >this problem? Please try to reply to me directly and I'll summarize >if anyone else is in the same boat, and interested. There's a simple test _procedure_. Put a write-enabled floppy (little window closed) in the drive, and pop up a directory-listing window. Take the floppy out, reinsert it (or any other write-enabled floppy) and hit ESCape. If the drive spins, you're OK. If the drive does not spin, you've got the problem. The problem mechs only do the wrong thing with write-enabled disks. To be sure, try this several times . -- Paul Smee, Computing Service, University of Bristol, Bristol BS8 1UD, UK P.Smee@bristol.ac.uk - ..!uunet!ukc!bsmail!p.smee - Tel +44 272 303132