Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uflorida!ukma!tut.cis.ohio-state.edu!rutgers!att!lzaz!hcj
From: hcj@lzaz.ATT.COM (HC Johnson)
Newsgroups: comp.sys.atari.st
Subject: Re: MMU GLUE chip clip 0 files message
Summary: Don't drop it, fix it!
Keywords: Disk Errors Hardwr Bug
Message-ID: <401@lzaz.ATT.COM>
Date: 3 Feb 89 15:31:20 GMT
References: <1029@sdcc15.ucsd.edu>
Organization: AT&T ISL Lincroft NJ USA
Lines: 29

In article <1029@sdcc15.ucsd.edu>, pa1575@sdcc15.ucsd.edu (pa1575) writes:
> Does anyone know a better solution to a flaky MMU/GLUE soket besides
> the "three inch solution" in BYTE a few years ago. My ST has been
> debilitated twice in three months to extent that  had to open it up
> and push the chips hard to reseat them. Ug . Now I am getting the
> flaky 0 files message that we have all come to know and love. I do
> have a chip clip that came with the machine but ....

I've two experiences with this kind of problem, on the Atari 800 and ST.

The underlying problem is that chips in sockets make imperfect connections.
Most chips, including all with tinned (silver colored) pins are meant to be
soldered, and will  oxidize in a socket.

The easiest fix is to :
1. remove the chip.
2. clean its pins (or bumps for a MMU) with care. NO sandpaper, but rubbing
   with a cloth is useful.
3. reinsert the chip.  The sliding of the contacts across each other is
   the important part.

The ST has 2 chips that are square, like the MMU.  The contact pressure on
the chip is quite low, so it is also possible that there is such a poor 
contact that it doesn't clean up when the chip is pressed back in.
There is no pat solution to this.

Howard C. Johnson
ATT Bell Labs
...lzaz!hcj