I think he was adding solder to bypass the blown ps17 fuse. Why he wont just answer anyone I can't grasp. Possibly he really didn't fix it and just showed a working one at the end
Its ipa also kown as isopropyl it drys quick with no left over oils or moister so its used to clean motherboards and ports so insure its cleaned effectiflly and safely but still buy labeled ipa for cleaning electronics coz some can b concentrated for different purposes like removing paint for sticky shit