From: Alan Pearce <kiwiantipodean@googlemail.com>
To: "piclist@mit.edu" <piclist@mit.edu>
Sender: "piclist-bounces@mit.edu" <piclist-bounces@mit.edu>
Date: Tue, 23 Mar 2021 12:17:59 -0700
Subject: Re: [EE]: 27xx64 EPROM Programmer
Thread-Topic: [EE]: 27xx64 EPROM Programmer
Thread-Index: AdcgGsVH9ZQ4taitSzC1bOdcOeL8/w==
Message-ID: <20210323191759.6cf1221a@raspberry>
References:
 <CAEBHKadKw+madL4A5Af2fUpO6Q_pheqB3OonTSAeDJiYoAN=HA@mail.gmail.com>
	<6059391D.25105.322DF01E@brent.eds.co.nz>
	<CACZQxzPeTgCQYgLNYff-Wm5W=jpt1aFaaOkMHUd9b55y3ZdO6w@mail.gmail.com>
	<BYAPR02MB40551EEA131B547BB0791E5DDC649@BYAPR02MB4055.namprd02.prod.outlook.com>
	<CACZQxzNJMfi41s=QHJLbJQmZ+=On0id2tn-pxcjbqDh5CGiXrw@mail.gmail.com>
In-Reply-To:
 <CACZQxzNJMfi41s=QHJLbJQmZ+=On0id2tn-pxcjbqDh5CGiXrw@mail.gmail.com>
Reply-To: Microcontroller discussion list - Public. <piclist@mit.edu>
Accept-Language: en-US
X-MS-Exchange-Organization-SenderIdResult: Pass
X-MS-Exchange-Organization-PRD: mit.edu
X-MS-TNEF-Correlator:
received-spf: Pass (protection.outlook.com: domain of googlemail.com
	designates 209.85.218.45 as permitted sender)
	receiver=protection.outlook.com; client-ip=209.85.218.45;
	helo=mail-ej1-f45.google.com;
dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed;	d=googlemail.com;
 s=20161025;
	h=from:date:to:subject:message-id:in-reply-to:references:organization
	:mime-version:content-transfer-encoding;
	bh=50Zms7qt55/wWA/9mL/PYrZD7iNZB43KA37UXi8/quQ=;
	b=eVLfr0VtucMKlO0M2ZRiwDLSI8W91uVipqFRbv6S81QgVJV6dBEs/WpcI/1M08bkWZ
	0PbUPccPoV3TgKqgOphlHg7vfFGVylV38+/Xx4CiAcrWgSGnM+OdWPA2Orq6LZmKO6b3
	4x7gu+9pR1tuO0uNRNs9hinWZgejVNfOtnXp76gOzAk50h4GKCBwjigJ1R19s/vtwO4J
	5xE8TQsGk4ZH4DQGhP1C/d7U8/tlQ3SBzGfW/u+WsPrq/W2+vhkagHiY1CNgKvqL6zZ6
	ofQvIdgjlzUvQWwNDRrKxq6Xw8UNU/5RhDZi84Q7u36z+lIgGKmNBevheIg14RIzfwik	23Wg==
authentication-results: spf=pass (sender IP is 209.85.218.45)
	smtp.mailfrom=googlemail.com; mit.edu;	dkim=pass (signature was verified)
	header.d=googlemail.com;mit.edu; dmarc=pass action=none
	header.from=googlemail.com;
errors-to: piclist-bounces@mit.edu
list-id: "Microcontroller discussion list - Public." <piclist.mit.edu>
list-post: <mailto:piclist@mit.edu>
x-beenthere: piclist@mit.edu
x-mailman-version: 2.1.6
x-received: by 2002:a17:907:ea3:: with SMTP id
	ho35mr6317919ejc.219.1616527082086; 	Tue, 23 Mar 2021 12:18:02 -0700 (PDT)
x-topics: [EE]
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0

On Tue, 23 Mar 2021 18:42:19 +1300
RussellMc <apptechnz@gmail.com> wrote:

> On Tue, 23 Mar 2021, 17:21 Bob Blick, <bobblick@outlook.com> wrote:
>=20
> > Regarding unapproved methods of erasing EPROMs, I have permanently
> > damaged some using both sunlight and germicidal lamps. =20
>=20
>=20
> Interesting.
>=20
> While cause of failure is hard to establish without forensic analysis
> ( if then) we were not of the impression that we lost any from
> sunshine erasure once we started ensuring that they were well
> protected against electrostatic damage. When UV exposed they seemed
> to be far more ESD sensitive when UV exposed.

I lost one (a 2708 IIRC) due to sunlight erasure. It had a clear window
which was a little convex on the outside and my theory was it acted as
a lens to focus the sunlight on the chip. Probably not a problem if the
window is 'frosted' as some EPROMs are.

I am also reminded of a story told at a NELCON conference I attended in
Wellington, where one of the presenters (from Australia IIRC) had been
involved in manufacture of a dummy body for the purposes of training
X-Ray technicians. The purpose was to have a system that could produce
a reasonable representation of working lungs while under investigation.
He managed to make a suitable machine based around an Intel 8080 board
IIRC. The machine was working great in its first test under the x-rays,
except that after a little while a limb would twitch, then resume
normal operation, then something else would twitch, and so things went
as time passed until eventually the whole mannequin was running rampant
on the X-ray table. So back to the workshop where it was determined
that the EPROMs had erased under the X-Rays. A permanent fix was made
by substituting bipolar fuseable link PROMs for the EPROMs.
--=20
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.