Hi,

It sounds like the connector to the display panel may be a bit lose or need reseating...

The display has a 10way ribbon cable that links it to the DSP board on the rear panel. I have had displays do similar things (i.e. generate random characters, flicker and go off) and had to end up carefully pulling the display unit off the front of the speaker and re-seating the little red ribbon-cable connector on the display PCB. Sometimes there is oxidation on the contacts and they are intermittent.

If you're not confident to do this, find a local tech who can sort it for you.

Cheers,

Steve

Main: 861v6 (LPS), 808v6, UHD722, DSP8000SE Anniversaries, DSP5200HC, DSP7200.2, SW1600, Sky Q, Cambridge Audio BD, Roon, M80
Office: 861v4 (LPS), 818v3, 800v4, HD621, M&K S150P, DSP5500HC, M&K MPS2810 sub x2
Son's system: 861v4, HD621, DSP6000.2, DSP5k.2C, DSP33, F80
Spare: MCD, 100 Series, 200 Series, 500 Series, C15s.