Implemented the weird Intel 82730 text coprocessor just enough to start displaying stuff. It stops here currently, error 32 means "cassette data failed" - might need i186 improvements, it enables an unsupported timer mode (that is used for cassette output): "FD3E7:ERROR! -unsupported timer mode 8013".
Does anyone know of any other system using the 82730? Surely there must be more than one