We just had an issue where the touch screen went completely unresponsive (same time as the robot control board died).
Out of nowhere the system shut down and wouldn’t restart. Swapped out pendants with another robot and discovered the touch screen issue. swapped out SD cards to rule that out for the startup problem.
Sent in the pendant for repair or swap. Waiting for that and a new control board.
If it’s a CB serie robot you can disconnect the RS-232 cable plug in the controller from the motherboard which is the TP touchscreen cable, not really long term fix but if somehow the touchscreen is jammed pressed it might help you out using a mouse in the meantime. Check section 5.3.5 of the CB service manual.