I have a Raspberry Pi 4B and have installed RetroPie on it (by flashing the image provided on the RetroPie site). In the beginning, connecting to my LG smart tv (43UM7600PLB) worked fine. After a while, I needed a couple of tries (it would say 'no signal', and then I'd fiddle with the cables, and in the end it would work). Bot nowadays, I can't get it to work at all. I keep getting 'no signal', no matter which HDMI port I choose on the tv, on the Raspberry Pi, and no matter in which order I plug the HDMI and power cables.
However, everything works perfectly fine on my 10 year old full-HD Panasonic "dumb" tv, and also on my cheap Acer computer screen. So the Raspberry Pi and RetroPie themselves seem to work just fine.
I've seen comments that not shutting down the device properly might break things, and to fix that I would need to re-install the SD card. But if that were the case, would things still work on these other displays?
I've googled around and tried all the things I could find. I connect the HDMI cable to the port closest to the power cable. I've tweaked
config.txt in various different ways, including
hdmi_force_hotplug=1, various combinations of
hdmi_group that people recommended in various forums.
The other day I enabled SSH and looked at the output of
pi@retropie:~ $ tvservice -l 1 attached device(s), display ID's are : Display Number 2, type HDMI 0 pi@retropie:~ $ tvservice -n [E] No device present pi@retropie:~ $ tvservice -s state 0x6 [DVI CUSTOM RGB full 4:3], 1024x768 @ 60.00Hz, progressive
So it looks like it doesn't recognise the tv at all, and now I'm at a loss for what to try next.
What could be the cause of this behaviour, and how can I fix it?
UPDATE after Dmitry's answer:
I have edited
config.txt and set
config_hdmi_boost=9. Now, if I ssh into the device and do
tvservice -n, it says
device_name=GSM-LG_TV in the console.
The tv itself still says 'no signal', though.