"myfathersson" wrote in message
...
Does anyone know if these two cartridges are in any way interchangeable
please?

I have a few 540As which do not fit the 320A slot: Can I change the end
pieces to make them fit or is there less to this similarity than meets the
eye?


You are right. Just change the two end pieces.
To avoid separating the two parts of the cartridge, change one by one, not
both at the same time.