[vcf-midatlantic] Good source for eproms?

Jonathan Gevaryahu jgevaryahu at gmail.com
Wed May 25 09:05:33 EDT 2016


Hmm. dump it 5 or 6 times, and note what addresses/bits are unstable.
Also, if your programmer supports it, try dropping the VCC voltage from 
5v to 4.95 or 4.90v, this often helps with decayed-floating-gate (aka 
"bit-rotten") eproms, since it affects the voltage threshhold for the '1 
vs 0' comparator per-bit.


On 5/25/2016 9:00 AM, Jason Perkins via vcf-midatlantic wrote:
> Johnathan,
>
> Don't worry, that's the first thing I did. I also found that after a
> couple reads a few bits had flipped!
>
> On Wed, May 25, 2016 at 7:27 AM, Jonathan Gevaryahu via
> vcf-midatlantic <vcf-midatlantic at lists.vintagecomputerfederation.org>
> wrote:
>> Be sure to dump the existing eprom first just to make sure that it is dead.
>> We've lost more firmware revisions than I can count (and yes, even
>> old/obsolete versions need to be preserved) by people just wiping and
>> reburning eproms without checking to see whether the version on it
>> originally was known or not.
>>
>> On 5/24/2016 11:22 PM, Jason Perkins via vcf-midatlantic wrote:
>>> I'm trying to get a Plus HardCard going again. Like many the ROM has
>>> forgotten some of its bits so I want to try installing a freshly
>>> flashed one.
>>>
>>> What's a good source for 7264s? Is it worth trying to get used ones on
>>> eBay? While I'm at it I'd like to track down a 2732 for an Apple
>>> ProFile formatting rom.
>>>
>>> Thanks,
>>>
>>
>> --
>> Jonathan Gevaryahu
>> jgevaryahu at gmail.com
>> jgevaryahu at hotmail.com
>>
>
>


-- 
Jonathan Gevaryahu
jgevaryahu at gmail.com
jgevaryahu at hotmail.com




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