[vcf-midatlantic] Good source for eproms?

[Jason Perkins]

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