V840 BIOS Primary Display - no video output

[foobounce]

I have changed the BIOS setting for the 'Primary Display' on a Celsius V840 and now have no video output.
Because I can't see anything I can't use the BIOS to change the setting back. Any ideas how I can get video output back?

Unfortunately, I can't see the BIOS screen now to see exactly what the setting was, but it was similar to:
'Primary display' and there were two options in a drop down that looked specific to my system.

It may be worth knowing that I have a graphics card that can drive 4 monitors (can't recall exact card but can look if relevant). There are two unusual video output ports on the card, a cable connects to one and splits into two DVI connectors. There is no motheboard video out.

The Celsius V840 is about 5 years old and I can't find any docs on the Fujitsu site for it. The only thing I can think of is to remove the BIOS battery. Is there a BIOS reset on the motherboard itself?

Thanks for any advice you can give.

[negotio]

Referring to your primary post https://forum.ts.fujitsu.com/forum/viewtopic.php?f=56&t=47097.

I do know of a reset button although I have not worked with a V840. The idea with the BIOS battery might work, although often the remove of the battery will not clear the settings.

Once upon a time...it was possible to clear even passwords this way

Does the machine boot up the OS?
Maybe Windows does recognize that no display is connected and switches to the correct outputs. Most graphic settings can be set in OS too. So maybe you can connect to the workstation from a second PC via RDP and correct the settings.

I found the manual for the Celsius V series. Unfortunately it is in German
I looked through it, but it does not mention anything about the BIOS. Mostly it just describes the disassembling to renew fans etc.