Hi there !
I’ve downloaded the Zynthian image here for my Zynthian Kit v4.6
https://os.zynthian.org/zynthianos-last-stable.zip
Twice.
Burned the image with raspberry tool :
Burned with Etcher
And my Zynthian don’t want to turn on, the screen doesn’t lit, red and green LED of the raspberry pi 4 are on.
… i’m afraid of one particular thing: I didn’t find anyone else with this same problem.
What should i do ?
I just completed my Zynthian late last night. I booted it up and it sat there for the longest time with a black screen. I looked through the back and I could see a red LED lit and the build instructions say it could take a long time. So I just let it sit and came back about 30 minutes later and it was up and running. Once up and running I checked for updates and let that go on for a while.
Did you verify all of your cable connections? How long did you let it sit before you determined it wasn’t working as expected?
Thanks for the answer. I let it on for five to 10 minutes maybe. I will try more.
I have checked the cables one more time too yes 
Did you had the same result as me when puting the images to the SD card ?
I couldn’t read the message on the screen (I only understand English). But using Etcher I flashed the image with no issues. If the latest stable isn’t flashing clean, that could be your issue. SD card issue?
Sorry I can’t help more. But the first boot may have been longer than 10 minutes. I was VERY nervous that I wired screwed something up and fried it. My suggestion is to boot it up and come back later. Watching it nervously will drive you crazy. 
Good luck!
The message say that what is written doesn’t seem 100% as it should after checking.
It’s the very first time that I see this message in my diy life.
17 minute now and still powered with no screen
I hope it will be okay before I leave home, and if not I will certainly buy a new SD card !
I’d try reflashing the image again. If it failed the check, that sounds like your problem. I can confirm that I used the same image and it flashed and verified 100%.
Ok. I will try a third micro-sd holder, in an other computer and see where it goes.
34 minutes and still black
If it’s still not coming up, take the kit apart and share photos of the connections.
Hi @Wapata , you will ended up with a non working setup so long you can’t write correctly the image to the SD card.
Also check that the image that you have downloaded is not corrupted.