Finding a TSX Node on an M800 suggests it's a takeover / replacement in the first place, as IIRC TSX Nodes were 'compatible' with the M Common Platform series but not the recommended item for new jobs.
Although admittedly it could just be someone using up older expander stock when the new panels came out. After all at a push these panels will even work backwards as far as the old 2 Zone TS expander, or LEC6 with caveats!
(The replacement, an MS Node, will emulate a TSX node, or even a TS900 node, if required)
Do you know for sure it has always worked before the crash?
And are you adding the nodes in the proper way by using the 'Equipment' menu etc...? Apols if you are familiar with the panel, but not TSX.
My experience with the M and x5 series has only ever been with the later MS Nodes, which require a fair amount of jumper config over and above other systems.