Fanuc issues

New here. Have an older Andi Stratos/SUP CNC, with a series Oi-MB Fanuc main processor. Had run great for years, but then began to stop recognizing or performing certain commands, such as tool change commands. Eventually stopped performing tool changes completely. Would get to that specific command in the program, and just freeze. No error codes, just stop. Tech support has been contacted numerous times, with no real progress. I eventually had to begin writing separate programs for each tool, and run them independently. Then, the program would run fine for a few runs, then would begin to freeze at the tool speed command. Once again, just stop, no error codes. After "resting" for a couple of hours, I could usually get it to run for a few more pieces. Also, since I had to manually change tools, I would need to enter M97 and M94 commands manually also. Now, Those commands are freezing up too. I enter the full M97 command for the current tool in the spindle, the 'go' light turns on, and nothing happens. The command does not leave the screen for me to enter the next command, just freezes. I suspect a Fanuc issue, but am at a loss for what to do.

Any help would be greatly appreciated. Thanks.