Plus keyboard not working

fred1212

Tinkerer
Jul 27, 2022
129
23
18
HI everyone
I have a Plus board that boots and the mouse works but not the keyboard. So far I have -
sounded the tracks from the keyboard socket to the TSG and the SCC(6522) and they are all good
Sounded through a keyboard cable as above
tried 2 known working keyboards
socketed and replaced the TSG and SCC
Anyone suggest what to look at next?
Thanks in advance