Superboard II REV B RS232 port has stopped working.

[royedmund]

I followed the Mark Csele instructions for setting up the RS232 port on my Superboard II several years ago and has worked brilliantlyuntil today.
When I use the SAVE command from BASIC the system just freezes and the LOAD command it doesn't freeze but unable to recieve programmes from the RS232 port.
The baud on the external PC is set to 300 baud.

PXL_20240222_111613024.jpg (292.66 KiB) Viewed 327 times

[Mark]

What value do you get when you enter
?PEEK(61440)

Also, are the RX & Tx Clock pins of 6850 (pins 3 & 4) getting a clock signal (16x your baud rate)?