Galaxy S4 refuses to turn on, no display output or vibration

Hello, I have a Samsung Galaxy S4 which refuses to turn on. Regardless of whatever I have tried, the phone will not boot into ODIN mode, fastboot, recovery, or the OS. The display, notification LED, and speakers are all not outputting anything. The phone does not vibrate (it does normally when turning on) either.

The only sign of life is whenever the phone is charging, the area around the camera becomes slightly warm.

I have tried, without any success:

• Swapping a known good battery from a friend's S4
• Trying to boot the phone while plugging it in
• Trying to boot into recovery/ODIN mode (Power + Home + VolUp / VolDown)
• Pulling the battery, holding the power button for 30 seconds, leaving the phone for half an hour, and reinserting the battery

My question is whether there is any way to at least diagnose which component of the phone is faulty, so I can buy replacement parts.

Logic board pictures: