Remove W138 from TB2-3.
Remove W12 from TB1-19.
Remove W13 from TB1-18.
Remove TB2 by removing two mounting screws.
Remove cathode lead of SCR from TB2-1.
Remove gate lead of SCR from TB2-3.
Remove SCR mounting nut, washer, and Iockwasher.
Apply thermal compound (Item No. 3
Install new SCR with washer, Iockwasher, nut.
Connect cathode lead of SCR to TB2-1.
Connect gate lead of SCR to TB2-3.
Replace TB2 to rear panel with two mounting screws.
Connect W138 to TB2-3.
Connect W12 to TB1-19.
Connect W13 to TB1-18.
Replace top cover.