tv repair

If you don't know what you are doing don't mess with it. Take it to a television repairman. CRT television run on very high voltages that can kill you if you don't know what you are doing.

That being said, are you running off of a cable box? Satellite? are you sure it's the tv that isn't getting the channels?

Are you missing channels 2-6, or 7-13? Are these OK and 14-22 are missing? The age and design of the tuner can make a difference in what causes the problem. You could be missing a band switching voltage. Many Tuners use a phase locked loop IC that fails often causing these symptoms. The black line is usually caused by an Electrolytic Capacitor in the vertical oscillator circuit that has either opened or changed value. This can be exceptionally difficult to troubleshoot. The quickest method is to bridge each suspect capacitor with a known good one (Use a 10uF 350 V Cap). Larger Values can cause severe damage to critical circuitry. If the bad cap has large capacitance, the 10 will show significant improvement though it may not restore full deflection. This must be done very carefully using an isolation transformer. Hot Chassis TV's can be a death trap. If you have not been properly trained, don't even think about trying it.

try it but don't try it?

If Guest had been trained he would be posting his own answer, maybe.

Maybe guest can say how long he did get lower channels before I didn't get lower channel, and what a lower channel is for him. And if anything happened which might have affected the antenna, and if he checked antenna and connections. Poorer reception on the low end of the channel range is not unusual. Best to try to solve one problem and hope (but not expect) it fixes the other. The tuner problem might be easier to solve if something if affecting "normal" reception as Guest has come to understand normal at his locale.

Since there are 2 problems check all power supplies. This is usually a good first start anyway. Other suggestions are good.