Amplifier transformer broke?

I have a 12 month old amplifier called Prosound, a Taiwanese
manufacturer, which has stopped outputting audio.

The electronic display appears to be fully functional, which is powered
by one main transformer. There are 3 main leads coming from it,
yellow/green, black, and the display power. The display power is
obviously working, the yellow/green is out putting 30V and 60V, however
the black lead is not reading anything.

Question. Could a transformer blow if it still outputs various other
voltages? If not, what else could it be? I've checked the fuses and
they're still ok.

Help appreciated.

Darren

.