X1 12v trigger output question.

Hi peoples 🙂
I have an X1 preamp, I have never used the 12v amp turn on.
I have lent the preamp to a friend who wants to use this but it doesn't seem to function.
Hes put a dvm on the terminals, then selected 'amp on' through the menu.
But the voltage stays at zero.

From the owners manual.
"The rear mounted pair of five-way binding posts are intended to control the on/off function of our own X series power amplifiers from the X1's front panel, or via the four button remote. When the preamp mode "Amp" is selected it allows the user to switch a nominal 12 volts DC at maximum draw of 50 milliamps to these binding posts."

Are we doing something wrong ?
Or does it sound like there's a fault ?
Personally I suspect there's a small transistor that's failed.
But without the unit on my bench, It's just a guess right now 🙂

Thanks.