From time to time we get a message saying a PAL we have doesn’t work. Usually when this happens there is little we can do as we no longer or never did own the PCB. On this occasion however we found a resolution.
Kyle point out that the file we had for Super Pacman 1M didn’t work for him. He claimed the equations for the PAL didn’t include the use of input pins 5 and 6. To back up his words with a schematic showing then attached.
The strange thing about this is he also dumped the PAL in his programmer and got the same output file as the original dumper (Channelmaniac) did.
From here Kyle built the 27C020 adapter and bruteforced his PAL chip. This time he got something that did work.
His recreation is now available for download in place of the old one.
I have a suspicion the Topmax programmer has a little bug in the handling of PAL10L8 chips although the other dump supplied by Channelmaniac supplied does work without issues so who knows.