Toshiba televison picture keeps going yellow

Sounds like the blue is disappearing from your picture. A common cause of this is bad solder connections which can cause the blue signal to be lost at several places. It could also be due to picture tube failure. Sadly, I'm leaning toward tube failure because of your description. Bad solder connections usually take some time to start acting up after you turn on the set, but you say this happens every time within a few seconds. This is typical of a picture tube failure where an internal connection is okay until the tube heats up, and that takes only a short time. A service shop could check the set to make a firm diagnosis, but if the tube is the culprit you should replace the TV. It's not economical to consider tube replacement.