[vcf-midatlantic] Good source for eproms?

Jason Perkins perkins.jason at gmail.com
Fri May 27 13:35:17 EDT 2016

There's a package inspection X-Ray machine at a recycler near me in
VA. It works... and I bet they would take $50 for it.

On Fri, May 27, 2016 at 1:32 PM, Chris Fala via vcf-midatlantic
<vcf-midatlantic at lists.vintagecomputerfederation.org> wrote:
> Oh, hey, somebody need an X-ray machine? Just see Dave! LOL
> On Fri, May 27, 2016 at 11:46 AM, Dave McGuire via vcf-midatlantic <
> vcf-midatlantic at lists.vintagecomputerfederation.org> wrote:
>> On 05/27/2016 11:02 AM, Herb Johnson via vcf-midatlantic wrote:
>> >>   They can be erased with X-rays.  EPROMs were originally designed to be
>> >> erased that way.  There are problems with that approach, however. (hence
>> >> the move to UV).
>> >
>> > The notion that one can plop non-quartz PROMs under an X-ray and erase
>> > them, has been mentioned here, and elsewhere for decades,  as a "could
>> > be done". But I'm not aware this has been, or is, any sort of common
>> > practice, much less an established procedure. I'm aware of 'theory', I
>> > know physics. I'm talking accepted practice.
>>   There is no accepted practice, but you and I know theory and physics,
>> so we know it's possible.  We've also read the documentation you
>> referenced below and know it had been done, and was originally the
>> intention for the product, but the approach had problems, so they moved
>> to an alternative method of erasure.
>> > Wikipedia....EPROM...citation 6...is a May 10 1971 article from
>> > Electonics Magazine by Dov Frohman, who apparently "invented the EPROM".
>> > Google.....
>> >
>> >  http://www.jmargolin.com/patents/eprom.htm
>> >
>> > references the article, and interviews the author later in 1993. The
>> > text say Intel shipped that 1702 EPROM "with a window because X-rays
>> > ....disrupted the structure" of the chip. The Web page has some details.
>> > I"ve not (yet) read the article, or checked the patent.
>> >
>> > This suggests that X-rays were not a production nor a customer practice.
>>   Yup.  But we already knew that. ;)
>> > so: Can you cite a reference I can find also, that shows a product
>> > announcement, or a production data sheet, that says specifically that a
>> > customer can erase a specific PROM product using X-rays of a particular
>> > wavelength and energy for a particular period of time?
>>   No.  I never said there were commercial products or production parts
>> that were intended to be erased with X-rays.
>>   I get the strong impression that you think I asserted that there were
>> production EPROMs which were intended to be erased in the field using
>> X-rays.  I made no such assertion.
>> > I'll grant the possibility this occurred for some very early product,
>> > some early development in the semiconductor lab, or some military or
>> > other specialized application.
>>   I think we can assume it had been done in the development lab because
>> the developer states that it "caused" a problem.  Not "could cause",
>> "may cause", but "caused".
>> > I'll grant some hackers could borrow a
>> > dental X-ray and erase an EPROM - did they do subsequent life-tests?
>> > Even that description would be of interest. Thank you.
>>   I have no idea if anyone has tried it outside of the original
>> development lab.  But I have an X-ray system, I could certainly try it
>> in my lab, or facilitate such experimentation here for others who have
>> more free time than I do.
>>                 -Dave
>> --
>> Dave McGuire, AK4HZ
>> New Kensington, PA

Jason Perkins
313 355 0085

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