Unable to enter the bios or grub

[donbastiano]

Hi, I "built" my first desktop and I'm having a strange problem.

I can use the monitor, LG 24MP59G, but I cannot see the bios nor grub, at the start I obtain the no signal message and the monitor turn off and sometimes, just before lightdm appears and shows my user, a message about a strange unsupported resolution, 960x1080.
The card is an MSI RX570 Armor 4GB, Tomahawk B350 the MB. With my two televisions, both LG, one HD ready, one FHD, I don't have any problem. I'm using the HDMI cable.

I read different versions of the problem, for instance in this video for a similar monitor, https://www.youtube.com/watch?v=MILk...tqRViIu&t=198s, the cause is said to be the freesync.

Any idea? I would like to understand also why if I try to enter the bios or stay on grub without see anything (i.e. just clicking the arrow down) and then connect the TV, it doesn't work, while if I connect the TV before start the system is ok? What do you think, it is a monitor problem or a GPU problem or even a MB problem or the combination? Or just my problem? ;(
I would like to not give it* back, maybe is not so good but there are very few alternatives.

[aht0]

try DVI or VGA connectors. Haven't found any other "cures".

I have identical reverse issue while using HDMI cable (GRUB/BIOS visible on PC screen, but not in TV).
Also with a Radeon card.

[donbastiano]

The problem is that the GPU doesn't have the VGA while the monitor doesn't have the DVI. The DP has the freesync but I don't have the cable I'm curious about how is possible to have such a problem, what could be the cause

[aht0]

VGA/DVI adapter?

and no. No clue as to why it would happen. Annoying though.

[donbastiano]

Well, for the moment there is a work-around, if the profile of the monitor in use has the FreeSync option ON, the problem is not present, at reboot the BIOS and GRUB are accessible. So I leave the FreeSync always ON, I don't know if there is some side effect i.e on power consumption or image quality

[aht0]

Wattmeter costs about 15-20 euros. Handy little tool.