iMac Intel 21.5" EMC 2805 Looping chime on booting
I finally fixed my imac. Here is steps:


I bought a new EFI chip from https://macunlocks.com/
I changed chip on mainboard my imac. 
Finally my mac was opened but lanuage was chinese and ask me efi password(new chip has no efi pass.)
Reset PRAM with CMD + Alt + P + R how to reset PRAM
Fixed! Imac living after 2 months later.


I founded solution and similar situation from here.