I just took out my Seaward PV150 which I bought when I started doing PV about 4 years ago. I haven't used it much and I need to check for ground faults. It won't work and is flashing an error code. They tell me at Seaward that it will cost $416 plus shipping to get it fixed. Does anyone have a favorite model of insulation tester? I think I would do better to buy a different model.