I've seen at a couple of GT-300 sites where the B10 error shows up every now and then. Sometimes it will take the machine down and sometimes it will recover and abort the Tri Color tilts. It seems to happen when the fill valve for the main tank shuts during the wash. This seems to effect the top boom home and/or boom pulsers.
I installed an MOV onto the fill valve and it has solved the B10 error. The MOV can be obtained free of charge from any Mark VII Distributor.
If this looks like what's happening at your site, you might want to look into it.