Issue with HDMI monitors and Raspberry Pi

[sgbaird]

I have a cocopar monitor, and the Raspberry Pi 4B for the science jubilee wasn't displaying. The monitor worked with my laptop, and the RPi 4B worked with a different monitor. Found https://forums.raspberrypi.com/viewtopic.php?t=34061, and I think the following should work:

I presume, you have installed your selected OS on SD card. Boot sector of the SD card is normally accessible from Windows, so you can edit file config.txt. What you maybe need?
Add into config.txt this line:

hdmi_force_hotplug=1
I experienced similar problem on one older LCD TV and this procedure helped.

[sgbaird]

Even with trying the other settings mentioned in the post, no luck. Maybe if I set that boost parameter to nine..