Looking at the pic it is definitly a horizontal hold problem. What I can't tell is whether there is also a vertical hold problem? Does the monitor roll vertically as well? If so these fail at the same time almost always due to a problem with the sync connection and the cap kit alone will not fix it although it may fix other issues. Look to make sure the sync connector or its wires are not loose. The sync connector runs from the game board to the monitor and is accompanied by the R,G,B, and ground connections. If this is not the original monitor for the game than this can be the problem. Depending on the game, the horizontal and vertical syncs can be seperate or combined into composite sync before being connected to the monitor. This connection may have to be modified to accomodate the swapped monitor usually by either adding or removing a jumper. Common symptons of a sync connection problem are a picture that can't quite be adjusted to hold or sync. Often it will sync momentarily then begin rolling again and have a very narrow adjustment range. Your monitor shows a horizontally rolling picture, but due to the much faster horizontal refresh rate (15,500hz) than the vertical(60hz) the human eye can't track it.