no screen but have volume?

If it a crt type, then probably a safety resistor has blown on the HT line feeding the tube base. The HT line is fed from the loptx so if you are not qualified then take to shop and mention the feed from the loptx to tube base. It could also be the loptx itself, depending on model, as some have audio power from psu, others loptx powers audio.but probably the safety type resistor has aged and gone. If unqualified please take to shop, as dangerous voltages are generated in line stage, and mains voltages in power supply.
I am a qualified British television engineer...

Terry
May 2012

Just a thought but have you checked your scart lead, if you are using one - mine sometimes comes loose and instead of using 0 to access my Virgin box, I have to use 57 ?????????
As I said, just a thought.

Wendy
May 2012