How exactly do PAL chips get programmed?

"Teo Zenios" wrote: depends. old original pals were fuse-link and hence OTP (one time programmable). At some point "GALS" came along which could be erased and reprogrammed (they are more like eeproms in their technology as I recall). In most cased you could replace a PAL with a GAL, as long as the speed of the part was correct. What's the part? if it's something like a 16L8 or a 22V10 then you should have no problem. It is possible to 'program' a pal such that it can't be read. If your pal has had this done you are out of luck. If it hasn't you should have not problem reading the contents. I actually had one and did some things with it but it was such a long time ago that I have no recollection, sorry. I do remember it ran a demo very quickly (I think it did fractals on the screen). I don't remember having to replace a pal, however. And I used it on a IIfx. -brad