DarrenF
Well-known member
I've been meaning to make up an adapter to try reading my Williams decoder PROMs (like the ones on Stargate, Joust, Robotron, etc. boards). I was waiting until I had enough on my list to order some 24-pin sockets, until I realized I had a pile of 40-pin sockets... duh.
So attached is a pic of the adapter I made for my GQ-4X. I read it as a 2716. Of course, I end up with the data 4x, as the 7641 is only 512 bytes and a 2716 is 2048 bytes.
To build one, just use 2 sockets; bend out pins 18 & 19 and tie to Vcc thru a 4.7K (or anything in the ballpark, it's just a pull-up); bend up pin 21 and tie to GND. Read as 2716.
To verify the data, I just took the "correct" decoder images and copied them over 4 times to make a repeated version, and used it to "verify". (copy /b file1+file1+file1+file1 file1x4)
So attached is a pic of the adapter I made for my GQ-4X. I read it as a 2716. Of course, I end up with the data 4x, as the 7641 is only 512 bytes and a 2716 is 2048 bytes.
To build one, just use 2 sockets; bend out pins 18 & 19 and tie to Vcc thru a 4.7K (or anything in the ballpark, it's just a pull-up); bend up pin 21 and tie to GND. Read as 2716.
To verify the data, I just took the "correct" decoder images and copied them over 4 times to make a repeated version, and used it to "verify". (copy /b file1+file1+file1+file1 file1x4)
