My tv write 3AMOK on the screen , when you press Any button ,it write 3AMOK What is the problem HITACHI

If you have a Hitachi remote HL02121, that means your TV model number is either 32PD7800 or 42PD7800.
According to the Owner's Manual the HDMI connector is activated by going to AV6.
While in the TV mode on the remote, press the '' button with the AV6 above it. That will tell the TV to use the HDMI input.
IF you don't have access to the TV remote, there are INPUT SELECTION buttons on the TV near the Lower Left hand Corner of the cabinet. Press the INPUT SELECTION button until AV6 is displayed on the screen (HDMI Input)

smps supply cant repair by check continuty on cable,,,power supply board faulty,,,should replace or repair by an expert professional

go to homme button reset settings ,,or try by restart the tv

Try unplugging the TV for 2 minutes and remove the batteries from your remote for 2 minutes also.

Just try to reset HDTV. If available and accessible, try using the reset buttons before using the steps below. Using the reset buttons can save time.
1. Unplug the TV power cord from the power outlet.
2. Unplug any connected devices (DVD, Set-top boxes, etc...)
3. Press and hold the TV power button for five seconds.
4. Plug the TV power cord back into the power outlet and turn on the TV.
5. Open the on-screen menu to confirm that the TV is responding again.
6. Turn off the TV and reconnect the devices.
7. Turn on the TV.

Regards:
VOTIT

A simple TV remote app, applications for your streaming device (such as Roku or Chromecast), and general streaming service apps are available (such as those for Netflix or Hulu). The app (s) that will be most beneficial to you will be determined by whether you primarily use your smart TV or a streaming device.

Digital main board.

unplug unit for 1 minute turn off main power button plug in then press main power button and try!

lift lid on front of tv just above the red power light. press the far right button labelled select. press exit to remove menu. use up and down arrows to navigate. you can download user manual from hitachi.com website.