[vcf-midatlantic] Good source for eproms?

Dave McGuire mcguire at neurotica.com
Thu May 26 00:48:50 EDT 2016


  Yup, "OTP" EPROMs.  There are microcontrollers of that sort as well, same
chips in different packaging.  Quartz windows and ceramic packages (which
are essentially required for quartz windows) are expensive, whole plastic
is cheap.  The idea is to develop and debug on erasable EEPROMs, then move
to OTP for production with no PCB changes.  Of course most of that has been
supplanted by flash memory technologies now, but EPROMs are still around.

                    -Dave

-- 
Dave McGuire, AK4HZ
New Kensington, PA



On May 25, 2016 7:14:46 AM Jason Perkins via vcf-midatlantic
<vcf-midatlantic at lists.vintagecomputerfederation.org> wrote:

> The EPROM on the drive now doesn't have a window. I thought that means
> it's only one time programmable?
>
> Dave, I'll drop you a line off-list. Thanks for the offer!
>
> -J
>
> On Tue, May 24, 2016 at 11:54 PM, Dave McGuire via vcf-midatlantic
> <vcf-midatlantic at lists.vintagecomputerfederation.org> wrote:
>>
>>   Yes.  The problem with EPROMs forgetting their contents is charge
>> leakage from the floating gates, not chip failure.
>>
>>   I have a metric assload of EPROMs (literally thousands) of nearly
>> every type, especially the really common ones like 2764s, if anyone
>> needs them.
>>
>>               -Dave
>>
>> On 05/24/2016 11:52 PM, Ian Primus via vcf-midatlantic wrote:
>>> Even if an EPROM has gotten corrupted, the chip itself should still be
>>> fine. Just erase and reprogram. I've yet to have a problem with doing
>>> this, it's quite rare to have a dead EPROM.
>>>
>>> Almost every EPROM I have has been scavenged from some sort of junk
>>> board or another. 2764's and 2732's are quite common, should not be
>>> hard to find.
>>>
>>> -Ian
>>>
>>> On Tue, May 24, 2016 at 11:22 PM, Jason Perkins via vcf-midatlantic
>>> <vcf-midatlantic at lists.vintagecomputerfederation.org> 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,
>>>>
>>>> --
>>>> Jason Perkins
>>
>>
>> --
>> Dave McGuire, AK4HZ
>> New Kensington, PA
>
>
>
> --
> Jason Perkins
> 313 355 0085





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