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whit3rd whit3rd is offline
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Default Seeking Opinon on EPROM Problems

On Monday, January 11, 2016 at 12:04:07 PM UTC-8, Geoffrey S. Mendelson wrote:
whit3rd wrote:
I wouldn't waste time erasing/reburning old parts (are they UV EPROMs, or flash, or EEPROM?), I'd just
program a flash replacement. The parts are cheap enough, and 'the better part of a day' is not.


The 27 series EPROMs are about $1 each from Chinese vendors on eBay. These
are used, erased and "tested". New ones in small quantities (yes, they are
still made) are around $40 each.


Electrical drop-in replacements in flash are not unavailable; 5V, 128k x 8bit Flash is
under a buck a chip at DigiKey, in PLCC packages that can be mounted in a socket
on an adapter to your (probably) DIP-style sockets.

If there's many sizes, though, it could be awkward to adapt to some of the old parts sockets.
It looks like the 32-pin DIP is still available, in 1M, 2M, 4M bit sizes. "SST39SF040-70-4C-PHE"
is the 4M version.