My friend borrowed my Xbox 360. After playing Skyrim for while he called me and asked what to do when the Xbox started showing a message "HDMI Mode not supported." I really didn't know what to tell him because I was not using HDMI for my setup. I suggested to look for solution online. I don't know what happened afterwards, but yesterday he brought it back and when I plugged it into my TV (using the RCA cable, you know the Yellow, White and Red) the screen first started showing snow-like lines and then it stayed mostly black. I could hear that the Xbox was working, and I could switch menus (they were making familiar sounds), I could also restart it and open the DVD tray, but I couldn't see anything on the screen. I also tried toggling the TV - HDTV switch on the cable itself, but that didn't help.
Can someone tell me what's going on and if there's a way to fix it?
PS. I remember that right before giving it to him I installed the latest (now is Jan. 2013) dashboard update by logging in to my Live account.
PS2. I tried resetting the display by holding down Y and right trigger while console loads. It doesn't do anything. The console restarts but the screen still remains black with these running lines across.
PS3. I also have another Xbox 360 (without an updated dashboard), so if I plug it in using the same cable, everything works fine.
Originally posted by peluynati: depending on what model it is, i would say its a light or 3 away from RROD! that is usually the sign when the GPU has lost contact with the board!
Thanks for the reply. Hmm. It doesn't show the RROD on the front though?
I had a similar issue happen before. What likely happened is that your friend tried an HDMI cable, which switches the dashboard input type...kind of like "upgrading" the desired input to HDMI. His TV wasnt supporting the HDMI signal, however (sometimes the signal can confuse the tv at times, depending on models such as the Sharp Aquos models. A quick turn off and back on of the tv usually solves that problem), so when you got the system back it is now expecting the new input. There is a setting in the video options of the console to switch it back, but the trouble is that you have to see it to change it (unless you can remember exactly what input is needed to choose it and switch).
My advice is to try your friends house again with his HDMI cable, and take yours as well. Switch back to composite, and when the screen asks if you can see it, choose yes and take out the HDMI cable. Normally you can just do a reset like you tried, but the new dashboard may not take input types into account. *shrugs*
