Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!crdgw1!rpi!uupsi!rodan.acs.syr.edu!amichiel From: amichiel@rodan.acs.syr.edu (Allen J Michielsen) Newsgroups: sci.electronics Subject: Re: I'm worried about EPROM labels.... Message-ID: <1991Feb24.165652.29617@rodan.acs.syr.edu> Date: 24 Feb 91 16:56:52 GMT References: <8505.27b915d3@jetson.uh.edu> <13650003@hp-and.HP.COM> Sender: amichiel@sunrise.acs.syr.edu Organization: Syracuse University, Syracuse, NY Lines: 43 In article <13650003@hp-and.HP.COM> panek@hp-and.HP.COM (Jon Panek) writes: >In <8505.27b915d3@jetson.uh.edu>, Larry Liska writes >> The recent postings about light-induced bit changes has given me pause. >>... I have been using file folder adhesive labels to cover EPROM windows. >> are all labels equal, or are there reasons not to continue using thin, >... These paper-based labels have proven completely reliable... >...these EPROMs are inside closed instruments, >Moral: if your parts are lying on a bench, exposed to flourescent lights, > etc, just let your random papers, databooks, schematics, manuals and > sandwich wrappers cover them up. That works pretty well, too. I've been following this rambling discussion from a distance. I too have heard the stories about trade show 'zaps' and don't doubt it's possibility. I do doubt (somehow) the 'reality' of the posts in regards to people who have claims to light power and frequency exposure measurements, as a 'hobby' experiment. The story I'll regale is quite the opposite. I changed dept's at my current employer 5 years ago. For 1 setup, they have a programmable experimental logic 'trainer' (a little microprocessor setup with software & i/o capabilities) used to teach by example real world analog and digital i/o and programming as it might be used for typical engineering control problems (tanks level control, automated machine control, conveyer system control...). This little thing sits on top of a bench and has all of it's cirtuitry exposed for further educational reasons. The bios software is contained in 4 16Kx1 (2716) roms. At that time, this thing was 4 years old. I was mortified to see that NONE of the roms have ANY covers on them at all for even further 'educationa emphasis'. This box is in a low ceiling room, with typical fluorscent lights that remain on 24 hours a day, 7 days a week, 52 weeks a year. These roms have been exposed to this for a total of 9 years now, and none of them have had a single problem. I'll open my door if anybody wishes to make a independant 'site inspection' because I don't believe it either, and I see it every day. Besides that, once a year the lab and equipment is used as photographic props for publication materials, and they do use flashes and reflectors.... I also will quickly add that when I program a chip, I NEVER leave it exposed like that (unless instructed to). I find it hard to believe that ANY rom that is put in a finished product would EVER have a reasonable expectancy to get enough uv light to cause problems. al -- Al. Michielsen, Mechanical & Aerospace Engineering, Syracuse University InterNet: amichiel@rodan.acs.syr.edu amichiel@sunrise.acs.syr.edu Bitnet: AMICHIEL@SUNRISE Brought to you by Super Global Mega Corp .com