Sonics E-Series - Manual (Page 13)

22) Check the diode D26 for a short by using a multimeter on the resistance setting. If it reads below 500 ohms,
replace it (Part no. 824-00012).
23) Inspect the clad around the K2 relay for arcing or any that is blown, especially around the areas where the
big coils plug into the board (#1,2,3,4). If there is any such evidence, remove the bad clad with a razor blade by
peeling it off the board and clean up any burnt material with a dremel tool or the razor blade. Jump any blown
clad with high voltage coax wire. Also check the back of the board for the same thing and repair as stated.