Start with safe basic checks
Test another known-working input and use the remote menu button. If menus are also invisible, the problem is probably inside the television rather than the connected device.
Step 2
A very faint image visible under room light can be associated with backlight failure on an LED television. Avoid opening the panel because screens are fragile and internal capacitors can retain charge.
Step 3
Power cycling once is reasonable, but repeated restarting can stress components. Note blinking indicator patterns and the exact model number for the technician.
When to book a technician
Panel, backlight, power board and mainboard repairs have different economics. Ask for a diagnosis and quote before approving parts.
Disconnect power where the manufacturer instructs. Do not open sealed electrical or refrigerant systems without proper training.