No signal from MacBook Pro '12

[kiwiflip]

I have this old MacBook Pro 13.3" from 2012 with a broken screen.

It still boots, but I can't see anything on the screen. A year ago or so I bought the HDMI adapter and plugged it into an LCD screen, and it was working fine, then suddenly it stopped working. When I plug it in now, there's no signal on the LCD screen. I guess there's no key you press on the MacBook to switch to an external screen...?

All the suggestions I find when googling assumes the laptop screen is already working (software updates etc).

Is there anything I can do?

 

[DeltaMac]

When you say the MBPro has a broken screen, is it visibly cracked? Do you get anything at all on that screen, Does it light up at all?
If it is not cracked, and you have what appears to be a black screen --- have you tried shining a bright light into the screen, just to see if any desktop menus or icons are visible on the screen (and the real problem is that the backlight has failed, so the screen is very dim, visible, but probably not usable.

Do you see ANYTHING on the external screen?
Try that with the lid closed: Boot the system, give it a couple of minutes to stabilize.
Connect the external screen, and wait another few seconds for it to recognize that external display.
Plug in a USB keyboard and mouse, then close the lid.
Then, press a key on the USB keyboard to wake the system.
Do you now see anything on the external screen?