Having more of a look at your picture just makes me more confused.

Like I said, the 6.6V feed around the tuners is only measuring 3.68V. This is obviously causing the output (meant to be 5V) measuring only 2.67V.

What could possibly be causing that 6.6V feed to be so low?

I noticed in the picture of the external tuners, there is one connection that requires 5V to the external tuners. In my mind, that may be a reason why my DVB-T tuners are not working.

Regards,
Hoffy.