jac@andante.UUCP (Jonathan Chandross) (07/09/88)
R. Allen "Urt" Wilkinson (urt@cmr.icst.nbs.gov) Writes: >computer but has stopped. The symptoms are drive activates and >"growns" like it always does but then it continues to spin non-stop ^-- that's spelled "groan". >until I stop it. Joel Sumner (oliver@thelink.UUCP) writes: >when it first came out. It turned out that later it began trashing some of my >Copy-Protected disks and trashing my ORIGINAL unprotected (but write protected) >disks when trying to make backups (i.e. Appleworks). It turned out that it >needed a fix on the board inside the Duo-Disk.. This is a very common problem with an uncommonly simple solution. The 74125 on the logic board in the drive has burned out. This causes the drive to write garbage all over your disk, whether or not it is write protected (look at the schematic -- it's after the write enable/disable circuitry). All you have to do is buy a new 74125 (less than a dollar) and install it. If you open up the disk drive, you'll see a logic board on top of a mechanical drive. The 74125 is in the center of the logic board (there is only 1 on the *whole* board so don't worry about getting the wrong one). Replace it and your troubles will vanish. I have fixed dozens of broken drives this way. An Apple dealer will charge 30 dollars for a 5 minute job. Nice profit. Send me mail if you have any questions. Jonathan A. Chandross rutgers!allegra!jac
kamath@reed.UUCP (Sean Kamath) (07/13/88)
In article <10863@andante.UUCP> jac@forte.UUCP (Jonathan Chandross) writes: >R. Allen "Urt" Wilkinson (urt@cmr.icst.nbs.gov) Writes: >This is a very common problem with an uncommonly simple solution. The 74125 >on the logic board in the drive has burned out. This causes the drive to >write garbage all over your disk, whether or not it is write protected (look >at the schematic -- it's after the write enable/disable circuitry). All you >have to do is buy a new 74125 (less than a dollar) and install it. > >Jonathan A. Chandross I do know that Apple has an authorized fix for DuoDisks. Seems they need to either change/replace/remove a capacitor on the analog card on those babies. I'd check and make sure you have a "good" one. I might be able to get serial numbers, but it should be easy enough through your local dealer. I'm not sure but I recall the stated symptoms match. Sean Kamath -- UUCP: {decvax allegra ucbcad ucbvax hplabs ihnp4}!tektronix!reed!kamath CSNET: reed!kamath@Tektronix.CSNET || BITNET: reed!kamath@PSUVAX1.BITNET ARPA: reed!kamath@PSUVAX1.CS.PSU.EDU US Snail: 3934 SE Boise, Portland, OR 97202-3126 (I hate 4 line .sigs!)