Plus 4 PLA versions and keyboard issue

[USA_Joe]

I have two Plus 4 computers. The one I recently acquired on ebay had a bad PLA, so I ordered a modern replacement. I received it over the weekend, and installed it today. The Plus 4 booted up with no blank screen like it had before. But when I try to use a cartridge or try the keyboard, neither worked.

So I swapped in an original PLA from my other Plus 4, and everything worked fine. Then I took the modern replacement PLA and put it in the Plus 4 that had the original PLA in it, and it boots and works fine (cartridge and keyboard). So with the PLA's swapped, both units work fine. When I put the replacement modern PLA back into the most recently acquired Plus 4, it goes back to having issues.

Is there different versions of the KERNAL out there that might be causing this? I'm at a loss as to why this is happening.

Thank you!

Joe

[MCes]

Hi Joe,
I'm interested in getting information on the "not very functional modern PLA" and... how did you solve it?

Thanks

[USA_Joe]

Sorry for the delay. I've been helping a friend who lost her house in one of the LA area fires.

I basically left what works alone, and moved on to other projects. I never did easily find what the issue was.

Joe