Dmitri, So do you suggest I send it to someone with a PC3K or try different heads?

Someone told that the terminal could be enabled with some overlays to upload in RAM

Do you have any clue of what this could mean?

Thank you

Cor

I put the heads back in the donor where they came from and they were fine. I also attempted with another headstack and got the same result.
That headstack is also still fine.

I would think that if it was platter damage it would just shutdown. I'm leaning towards ROM damage but it does see the serial and model #.