Path: news.weeg.uiowa.edu!news.uiowa.edu!hobbes.physics.uiowa.edu!zaphod.mps.ohio-state.edu!howland.reston.ans.net!agate!dog.ee.lbl.gov!ucbvax!CS1.PRESBY.EDU!sebugg From: sebugg@CS1.PRESBY.EDU (Stephen Buggie) Newsgroups: comp.sys.apple2 Subject: Re: Ancient Boards Message-ID: <9304271724.AA02830@cs1.presby.edu> Date: 27 Apr 93 17:24:17 GMT Sender: daemon@ucbvax.BERKELEY.EDU Distribution: world Organization: The Internet Lines: 11 Regarding the Disk ][ drive that spins but does not step across the tracks, I had a similar problem with a Disk ][ which was ciured by replacing the 74LS125 chip. (During the problem that, that disk drive also prevented the other disk drive from operating.) If that does not work, then replace also the ULN2003 chip. These are commonly available low cost chips. Stephen Buggie 888888888888888888888888888888888888888888888888888888888888888888888888888 88 Stephen Buggie Psych Dept Presbyterian College Clinton SC 29325 88 88 sebugg@presby.edu voice: (803) 833-8337 or 833-1632 88 88 IIe/IIc loyalist 88 888888888888888888888888888888888888888888888888888888888888888888888888888 Path: news1.icaen!news.uiowa.edu!news1.chicago.iagnet.net!iagnet.net!newsfeed.internetmci.com!206.229.87.25!news-peer.sprintlink.net!news-pull.sprintlink.net!news-in-east.sprintlink.net!news.sprintlink.net!Sprint!151.164.1.34!swbell!not-for-mail From: Rubywand Newsgroups: comp.sys.apple2 Subject: Re: Need help with dead Disk II drives Date: Sun, 30 Nov 1997 19:48:29 -0600 Organization: Southwestern Bell Internet Services, Richardson, TX Lines: 39 Message-ID: <3482176D.35ED77D2@swbell.net> References: <34809db2.14805181@news.mindspring.com> NNTP-Posting-Host: ppp-207-193-10-68.hstntx.swbell.net Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Trace: nnrp1.rcsntx.swbell.net 880940810 2345 (None) 207.193.10.68 X-Complaints-To: usenet@nnrp1.rcsntx.swbell.net X-Mailer: Mozilla 4.04 [en] (Win95; I) Bob Danielson writes ... > > They chatter for about three seconds when first powered up , then just > merrily spin along indefinitely with no attempt to find the boot > sector on the diskette. > > Is there anything I can try at home before biting the bullet and > trying to buy replacements? > You could try some tests; but, they're more trouble than the fix tries, so we'll just cut to the chase. Basically, it sounds like Drive 2 does not know when to stay OFF. There are three fairly high-probability places where a glitch may cause this to happen: 1. The 74LS132 on the Disk ][ Controller card may have a blown gate or some pins may be making poor or no contact. Try unplugging and re-socketing the IC. This usually takes care of bad contact problems. (Or, you can replace the 74LS132 IC with another 74LS132 or 74132. A 74LS00 or 7400 may work, too.) Also unplug and re-socket the 9334 and 556. 2. The ULN2003 IC on the Drive 2 main circuit board may have a bad gate or may have developed some poor pin-to-socket contacts. Remove the drive cover. Unplug and re-socket the ULN2003 IC. (Directly replacing a blown ULN2003 could be difficult. If you do not mind doing some rewiring, a couple 7404's should get the job done.) 3. Drive 2's cable may have developed a short between pins 14 and 16. Mark the position of the cable at the Controller card and at the Drive 2 circuit board and unplug the cable at each end. Use an Ohm meter to check for shorts between adjacent pins. If you find a short between 14 and any other pin you can try repairing the cable or cutting out line 14 and running a new lead; or you can get a replacement cable. Rubywand