Path: news.uiowa.edu!chi-news.cic.net!newsxfer2.itd.umich.edu!agate!news.mindlink.net!van-bc!pm060.bby.wis.net!user From: dmanzer@wimsey.com (Doug Manzer) Newsgroups: comp.sys.apple2 Subject: Re: Disk II - analogue card... Date: Mon, 29 Jan 1996 16:20:07 -0800 Organization: Online at Wimsey Lines: 38 Message-ID: References: <4eiovf$g3p@yama.mcc.ac.uk> NNTP-Posting-Host: pm060.bby.wis.net In article <4eiovf$g3p@yama.mcc.ac.uk>, duncane@jumper.mcc.ac.uk (Duncan Entwisle) wrote: > I've managed to (i) blow a card by plugging the drive card in while the > machine was on (thicky!) and (2) blow the card in another drive while > swapping drives around to test which drives had blown (double thicky!) by > misaligning the connectors. > > Is there a FAQ or an site with information about fixing the things? Does > anyone have any experience of these (I doubt I can be the only one to be > ham-fisted like this :-) Don't know about a FAQ, but the usual result of plugging a Disk ][ interface card into the Apple while power is on is to blow the 74LS125 on the analog card (inside the Disk ][ drive case). This causes the drive to then destroy (while spinning) all data under the read head of any disk in the drive. If you try to boot a disk with such a damaged drive, one of the following will occur: a. If the head is already positioned at track 0, it will wipe out that track only. In the case of ProDos, this is the catalog track, so the files are pretty well history, unless there's a utility to rebuild the catalog. DOS 3.3 is not as bad, as track 0 is an o/s boot track (it's always the same) so if you put the disk in a good drive you can still catalog and get data from it, but you can't boot (unless you rebuild that track, with Locksmith, etc.) b. If the head happened to be positioned other than track 0, for instance on track 32 then as the drive spins up and the head is stepped back to track 0 it will leave a spiral swath of destruction all through your entire disk, effectively trashing everything. Usually, replacing the LS125 fixes the analog board. To test it, format (and make bootable) a spare floppy disk with a good drive and then attempt to boot it with the repaired drive. If it boots up, fine; if not then there are more problems. Regards, D.M. Path: news.uiowa.edu!chi-news.cic.net!nntp.coast.net!zombie.ncsc.mil!news.mathworks.com!newsfeed.internetmci.com!in1.uu.net!newstf01.news.aol.com!newsbf02.news.aol.com!not-for-mail From: rubywand@aol.com (RUBYWAND) Newsgroups: comp.sys.apple2 Subject: Re: Disk II - analogue card... Date: 30 Jan 1996 08:46:16 -0500 Organization: America Online, Inc. (1-800-827-6364) Lines: 54 Sender: root@newsbf02.news.aol.com Message-ID: <4el7f8$9ao@newsbf02.news.aol.com> References: <4eiovf$g3p@yama.mcc.ac.uk> NNTP-Posting-Host: newsbf02.mail.aol.com X-Newsreader: AOL Offline Reader In article <4eiovf$g3p@yama.mcc.ac.uk>, duncane@jumper.mcc.ac.uk (Duncan Entwisle) writes: > >I've managed to (i) blow a card by plugging the drive card in while the >machine was on (thicky!) and (2) blow the card in another drive while >swapping drives around to test which drives had blown (double thicky!) by >misaligning the connectors. > It would be interesting to do your biorhythm chart for the day on which the above events transpired. >Is there a FAQ or an site with information about fixing the things? Does >anyone have any experience of these (I doubt I can be the only one to be >ham-fisted like this :-) I do not know about an FAQ or EBS for the problems mentioned. Regarding the misalignment, there seems to be a chance that either +12V or -12V ended up going to the board's +5V rail. (See diagram on page 146 of The DOS Manual.) Bad news! On the other hand, it does not seem very likely that the generic drive electronics were zapped. With luck, you fused an input capacitor to a short before any IC's blew. Otherwise, pull the 74LS125 and ULN 2003. Stick 'em on a breadboard and check for correct operation. (The 74LS125 is a common part, easy to replace. The ULN 2003 seems to be 7 TTL inverters. If you can't find one, try substituting inverters from a couple 7404's.) If, with the above IC's checked-out and in place, the board does not work, then, you will need to check/replace the other IC's and the transistors. (The MPSU51, Q1, can be any PNP silicon power transistor with decent gain. Similarly, if a CA3146 transistor array IC is hard to find, you can substitute 2N3905's for the NPN's and 2N3906's for the PNP's.) Of course, the easiest alternative is to buy a couple old Disk II's and swap-in their analog boards. Rubywand