The picture is only comming in as a small band across the tv

Hello
The vertical scan output section of your Symphonic is faulty. This type of fault may occur either by the defect of output IC or its terminal soldering loose contacts or capacitor problems. Just open your TV, and locate the vertical output section, and the IC used there. It will be a small IC usually screwed onto a metal heatsink, to radiate heat out from it. Resoder all the terminal solderings of that IC, by applying a little more solder, without making any solder bridge short in between its terminals and see the effect. If it does not helps, replace the capacitors used in that section. Replace them all with same type. There will be 5 or 6 of them. If this also doesn't helps you, replace the Vertical Output IC, with same type and number. Ok.