Did you ever get this Fixed? I am also having an issue with a TAC 20. Same issue. However it does not have an 188 board. 6300RD3 CPU board and 6300RE3 mother board.
That’s a TAC20-03. If the GET doesn’t clear it up you’ll probably have to replace the CPU. You could try re-loading the software if you had a backup but definitely do a transfer download ASAP. With any luck the job file will be okay when you load it in the new board.