replace an EPROM with an EEPROM?

[Roger Heflin]

On Fri, 29 Jan 1999 Tedscj at aol.com wrote:

> Has anyone tried to replace an Eprom with and EEprom?
> Specifically, Replace the 27c256 in a Memcal with a 28256?
> Does anyone know if it would work?  or is the pinout somehow different?
> The reason I'm interested in doing this is because it would be more economical
> and efficient.
>

I would be interested in this answer.    That would accelerate the
erasing and reprogramming cycle quite a bit.
 
> Also, what do people do about removing and replacing their Eproms from the
> Memcals when reprogramming them?  Do you solder in ZIF sockets?
> 

Get a IDC wire wrap socket, and modify it with a dremel type tool, (it
is already the correct width and spacing to plug a memcal into, the
slots are wrong though, and it won't be long enough) and modify it to
allow you to plug the memcal in.   Bend the wire wrap socket's legs
enough to plug it into the programmer, and then just leave it there
and plug the memcal into it.   You will only have about 1/2 of the
memcal plugged into the IDC socket and the rest will be unconnected,
but nothing left is part of the prom.  YOu will need to figure the
correct way to plug it in (both the socket into the programmer and the
memcal into the socket) I have done then and used it to read out my
memcals, to do the erasing you would have to take off the top of the
memcal, and the window cover and put the whole thing in the eraser.


> I want to start lookin at and modifying my Memcal, but have never done any of
> this stuff before.
> 
> Thanks,
> Ted
>