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