Ti Desktop starts with white display

[Infra]

OK so I bought a Virus TI as defective VERY cheap, to fix it yourself
The previous owner wrote following on the official Virus forum.

"Just tried starting my Ti Desktop after it's been in (climate-controlled) storage for 4 years and it starts with a white display. It does seem to work partly because the leds change when I press the program button so it looks like it changes program but I can't get any sound out of it.

I searched the forum and found this thread Can't start/update my virus TI Desktop and tried the suggestions there but no luck.
The Virus control center has no problem communicating with the device and reports it as having the latest OS."

Any ideas? I want this baby up running