My screen goes from a normal picture to a green screen with lighter green horizontal lines. Ocassionally, it will switch back to a normal picture, but lately it is taking longer to do so, or it doesn't switch back at all. Sometimes, if I turn the tv off then back on, it will correct the problem.

Hello
The fault to this Trinitron TV is loose soldering ofcourse. Check all the soldering points at the video output card, which can be located at the base of the picture tube. Normally the components fitted on this board will heat up while working, and repeated heating and cooling will make the solder terminals of the componets to get loose contacted. Just pull out the CRT base board from the CRT causiously without make a damage to picture tube pins. Look for any loose solderings at this board. It is quite difficult to detect these loose solder points as some of them will be microscoppicaly small and can be seen with the help of a magnifying glass. Just do what we do at service table. Just resolder all the suspected solder points by applying a little more solder, without making any solder bridge short between adjecent solder terminals. In most cases, nearly 85%, the fault will be cleared out with this process. Check the plug in connection wire [comes from main board to picture tube base board] for any loose connection. Just pull it out from the main board, and reinsert it for at least two times. If any loose connections to this wire connection, this will clear out it. OK.