did u check the A/C, defrost, cycle running pressures....i have had a ton of indoor TXV's cause defrost problems. on that CB19 it may be a what i call a double barrel type, if so it will be 3/8 flare fitting on liquid line. there is a kit for these..56j19 is probley the TXV, NOT 100% on that. the kit is seperate, its just a few brass fittings with gaskets.