I have read the related topics in this forum and read the fetch TV users guide again (https://www.fetchtv.com.au/pdf/fetchtv_user_guide.pdf). And I still cannot solve my issue. After I turned on the TV (the fetch tv box is always on and the antenna is connected to the fetch TV box first and then connect to the TV ), and switch to the fretch box HDMI connection source, I always saw the blank (black) screen.
I have tried to unplug the fetch TV box ans waited for 30 seconds, and put the power back on, then I saw the TV screen displayed "preparing the system, please wait ..." And after the message disappeared, the same blank screen show up again.
I also tried turned it back on and press red, green, yellow, blue buttons (and the reverse order) and nothing happened, just the same message ("preparing the system, please wait ...") displayed and then, same blank screen.
And when I press the buttons in the remote, the record button in the box was flashing in blue light and the STB button in the remote was flashing in red light. When no button was pressed in remote, the first two lights were on in blue colour. I think they were (power and Internet). By the way, the Internet connection in my home is fine.
I have put some images below to show my situation. Hope that will help.
It does seem likely your Fetch box is defective. The fact you get the initial "Preparing..." message indicate everything else is working ok. Couple of thoughts:
1) Just to confirm the hard reset sequence is Blue, Yellow, Green, Red individually from Right to Left
2) Check you TV HDMI settings menu. It might have some mode or hdmi power option that you could switch off.
3) Try checking on a different TV. You only need a HDMI cable and the fetch box to see if the unit will boot to the full setup menu.
4) Otherwise contact Optus Live Chat and request they send out a replacement box.
This recently happened to our Fetch TV box too. Could not find a fix, it's simply defective. Have just received a new box in the mail and sending the old one back. You will need to get in contact with Optus to arrange this.