Apologies all,
previous message XTAL frequency wrong
trim
> BAUD_LOOPS      EQU     D'251'  ;1200 BAUD @ 5.58 MHz trim (transmit parity de
mo)
SHOULD READ:
BAUD_LOOPS      EQU     D'251'  ;1200 BAUD @ 3.58 MHz

ie a 3.58 MHz common colour burst crystal or resonator.