Your Android headunit has been running flawlessly for a couple of months, and then suddenly, it’s not working. There is a black screen and no display, but it doesn’t work now.
Check for power
Every Android headunit needs power. The 12v system powers the head unit, and you need to check for a 12v supply being present at the headunit loom and the GND or earth also being present to make a circuit.
Fuses protect the 12v circuits, and several fuses can be involved in the supply to the Android headunit. Checking for 12v at the head unit plug is a fast way to check all those fuses in one test. If you have a 12v supply at the power pin of the headunit, then your fuses are good.
No power at the rear of the headunit or on the can bus box can indicate a blown fuse. You would need to change the fuse and see if it blows again. Check for a trapped or chafed supply cable if the replacement fuse also blows.
All tests passed the black screen.
If your power checks are passed, you get a good 12v supply to the power plug; look for the CAN BUS BOX if there is one. The can bus box can control the on/off of the Android headunit, so try a replacement CAN BUS BOX if you suspect this could be faulty.
If you have power to the headunit and there is no can bus box, you could have one of the many non-working Android head units. They follow a familiar pattern: working ideally one moment, then just not working, a black screen. No sound and no picture are due to a bad motherboard.
Magic Reset Button (RST)
You can try pressing the reset (RST) button if you can find it. This will power-cycle the headunit. You have probably tried unplugging the power connector from the headunit while testing for the 12v supplies being present, but pressing that tiny button with the end of a SIM eject tool just one more time can help you feel that you have tried everything.
The Android headunits are not unknown to fail very quickly, and although some struggle for years, quite a few only make it to 18 months or so. The repair cost can outstrip the cost of replacement, and after 18 months, the technology has moved on anyway. This could be a good excuse to replace it with a later model, just as you would with a phone.