28 pin IC adapted to 24 pin socket

[+hueyjones70]

I recently read a post that described a homebrew method of adapting a 28 pin IC to a 24 pin socket. I remember that it involved jumpers between some of the pins and that's all I can remember. Can someone direct me to that topic or does anyone have knowledge of this method. I am interested because I have BASIC C on a 28 pin IC and I would like to install it in an Atari 800XL without having to use an adapter board.

[+Nezgar]

An adapter is pretty much a requirement to use a 28 pin 2764 EPROM to replace the original 24 pin 2364 BASIC Mask ROM in an 800XL.

 

The 600XL motherboard actually has thru holes for a 28 pin socket, and a few jumpers can be moved to allow it to use a 2764 EPROM directly.

 

If you dont want to purchase an adapter, you can try building one yourself with 2 stacked sockets, take a look at this page: https://ist.uwaterloo.ca/~schepers/sockets.html

[+hueyjones70]

I have been using adapters but I have also been using a piggyback ROM setup for a dual OS.  I have to solder resistors on the side of the piggyback next to the adapter and the adapter has to be cut in order to fit in beside the piggyback setup. As I was typing this I just visualized a way to move the resistors out of the way.

[Kyle22]

You can also use a 24 pin 68764 / 68766 EPROM, but they have gotten quite expensive.

https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=68764+eprom&_sacat=0&LH_TitleDesc=0&_osacat=0&_odkw=68766+eprom

https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=68766+eprom&_sacat=0&LH_TitleDesc=0&_osacat=0&_odkw=68764+eprom