'63 GE B&W clarity troubles

[jpdylon]

I would look to the tuner section first if its becoming grainy and snowy. Sounds like an RF tube that's going bad after it heats up. Also check the IF and video strip as mentioned. i doubt that its related to the vertical section because the grainy picture leads to the rolling and instability. I would also look at the sync and AGC sections. You may have a faulty AGC delay line as well.