Power Steering

I'm new to this forum and just bought a 76 t-top so I have a few issues with it. The power steering does'nt work. I put a used pump on but that did not fix it. How do I know if I need a new control valve or steering cylinder. Is there a way to check for this ?
Zeeth

i would replace both. make it like new

I have replaced both the control valve and the cylinder. Checked the pump(it has 300 lbs0 of pressure. still no power steering.

the only thing left is a blocked line somewhere. check all lines and hoses for blockages. is there a filter? if so remove it