I had reception problems when my TT was new. I found that when they put some of the ends on the cables at the factory, they simply cut through the shield and connected just the center wire.
So you may want to check them with an ohm meter. Disconnect the cable at both ends and measure between the center wire and shield. It should be open - no reading on the meter.
Then short one end by placing something metal between the center wire and shield. Measure the other end and it should show very low resistance - maybe a couple of ohms.