Hello OM-s

I have recently bought an Yaesu YR-901 CW-RTTY decoder with the user
manual.
I connect it from the composite video output to a monitor.
But always when I turn it on the screen is full of a mix of occidental
and japanese characters. The reset/clear buttons do nothing. Always
the same. When incoming signal the screen does not change but the
vumeter seems to work.

Is the memory of my device broken ?

Please help.

73-s from Iñigo. EB2DTP-EC2AHB
eb2dtpATea2rcf.com