I worked at an Apple repair facility that was part of a large county agency serving public school districts. We didn't charge a minimum fee, so we typically did the job while you watched. Pushing all of the chips back into the motherboard was called "the laying on of hands." The other quick fix was taking a pencil eraser to the edge connector of the disc controller board, which was known to use inferior gold plating.
I remember people were horrified when the IBM PC came out with soldered-in chips, but IBM published a solid report showing that the chips were more reliable than the sockets.
Oh IBM's first MCA PS/2 PC's had a wonderful issue in some models. They used a daughter card to present the expansion slots. Many had a habit of placing the monitor upon the top of the case (as was norm back then) and a gentle tap would momentarily wiggle that daughter card due to the case bearing the monitors weight and cause the system to lock right up.
Solution - don't put the monitor upon the PC case was not a happy solution for many, but was the solution.
I remember people were horrified when the IBM PC came out with soldered-in chips, but IBM published a solid report showing that the chips were more reliable than the sockets.