I have the same problem with K6501.
Red LED (LINE) was burned, and T7and R33 is destroyed.
I am in Croatia. I changed some elements (R33,D1-14,ZD1,ZD2,ZD4,ZD5, C4-C9,Red LED,T1-T6).
Operate with SW1 its works, but when I call the kit is answer but I can not input anything and not hear enything.
Probably due to lightning strike.
Check path from processor via transformer to line connection.