E74, 1 flashing red light
The E74 fault is also a common Xbox 360 fault. I have repaired a lot of Xbox 360’s that have had this fault. People say the the main cause is the ANA/HANA chip but other say not. All the ones I have repaired have not had a problem with the ANA/HANA chip, it has been down to the GPU yet again, It is sometimes dry/cold solder underneath the GPU but usually, E74 is a failing GPU.
Click for E74 Repair (GPU Replacement)
Other Error with a single red light are
E45: (unknown)
E64: E65: E66: DVD Drive Error, Drive firmware error
E67: E68: E69: E79 Hard Drive Error… It could be a problem with the Hard Drive itself or a problem with the internal connection to the hard drive, Try removing the hard drive and playing without it or check the connection on the hard drive.
E71: possibly a dashboard update error, Bad nand, bad nand flash or Southbridge Problem
E72: (unknown)
E73: Ethernet port problem, But mainly GPU problem
E75: Network IC problem
E76: (unknown)