[vcf-midatlantic] Good source for eproms?

Jason Perkins perkins.jason at gmail.com
Fri May 27 13:43:10 EDT 2016

Perhaps we are drifting off topic here... the machine that's local to
me is from the late 70s. It has no camera system, you put your face up
to a viewing window and peer in (!!!).

I'd want to be sure I wasn't irradiating myself before using the machine.

On Fri, May 27, 2016 at 1:37 PM, Dave McGuire via vcf-midatlantic
<vcf-midatlantic at lists.vintagecomputerfederation.org> wrote:
>   FYI, at least one "package inspection" X-ray machine is identical,
> except for the sticker on the front, to a model marketed to assembly
> firms for weld inspection and PCB inspection.  Mine is such a machine.
> Needless to say it was a very good deal. =)
>   These are awfully, awfully heavy though...much more so than their size
> would suggest, due to all the lead.  Be careful.
>                -Dave
> On 05/27/2016 01:35 PM, Jason Perkins via vcf-midatlantic wrote:
>> 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
> --
> Dave McGuire, AK4HZ
> New Kensington, PA

Jason Perkins
313 355 0085

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