Path: utzoo!mnetor!uunet!seismo!sundc!pitstop!sun!decwrl!ucbvax!CORY.BERKELEY.EDU!dillon From: dillon@CORY.BERKELEY.EDU (Matt Dillon) Newsgroups: comp.sys.amiga Subject: Re: Have you had a lot of bad floppies lately with your A500? The answer! Message-ID: <8805100305.AA09860@cory.Berkeley.EDU> Date: 10 May 88 03:05:11 GMT Sender: daemon@ucbvax.BERKELEY.EDU Lines: 23 :with that disk even with many writes. These symptoms seemed to indicate :that there was a problem with many of my bulk floppies. HOWEVER, THIS :CONCLUSION WAS WRONG!! My problem turned out to be the A500 power supply. :My configuration is: : : A500 with .5M extra memory (A501 look alike), one extra 3.5" : floppy (not the A1010) which is an IBM floppy made to run on : the Amiga using a couple of 74LS chips as has been discussed : on the net, and a standard A500 power supply. : :I substituted an IBM 150 watt power supply for my A500 power supply and haven't :had a bad disk yet. (I noticed that I had to reformat some of the previously Sounds like either you forgot some bypass capacitors on the LS TTL or you were overloading the poor A500 power supply with the combination LS TTL and foreign disk. Have you checked the amount of power the floppy + support LS TTL is pulling? An IBM 150 watt power supply could certainly (appear to) fix both problems. Where are you pulling the 5V for the LS TTL from? How many chips and of what type are they? Are they *all* LS? Apart from simple LS gates (4-8 ma avg), some of the MSI LS parts pull 80+ ma! -Matt