Page 4 of KNB1 Noise Blanker "Assembly and Operating Instructions": "the toroid core for inducton L2 is marked with an orange dot to differentiate it from L1. Be sure to use the correct cores in the following steps. Problem: both cores are the same with neither having an orange dot. Advise please. Many thanks. 73 Charlie WA4HKN K1-4 #1074 ===================