3-1-1-1 - Check if the indicator lights on the control board and the power LED on the mini PC are lit. 

• Result 1 - The control board and the mini PC are lit. 
  Start 3-1-2-1.
  
  
• Result 2 - The indicator lights on the control board are not lit. 
  Start 3-1-1-2.
  
  
• Result 3 - The power LED on the mini PC is not lit.
  Start 3-1-1-4.

3-1-1-2 - Measure the voltage at the “b25_24V in” connector on the control board. The expected reading should be 24V.

• Result 1 - The reading is 24V. 
  Start 3-1-1-4.
  
  
• Result 2 - The reading is not 24V. 
  Start 3-1-1-3.

3-1-1-3 - Replace the power supply (see SOP here) and verify successful machine startup and touchscreen functionality.

• Result 1 - The touchscreen works fine. 
  Issue close.
  Root cause: The power supply fails.
  
  
• Result 2 - The touchscreen is still blank. 
  Start 3-1-1-4.

3-1-1-4 - Measure the voltage at the "b35_J_PC_PWR (Power)" connector on the control board. The expected reading should be 12V.

• Result 1 - The reading is 12V. 
  Start 3-1-1-6.
  
  
• Result 2 - The reading is not 12V. 
  Start 3-1-1-5.

3-1-1-5 - Replace the control board (see SOP here) and verify successful machine startup and touchscreen functionality.

• Result 1 - The touchscreen works fine. 
  Issue close.
  Root cause: "b35_J_PC_PWR (Power)" connector on the control board fails.
  
  
• Result 2 - The touchscreen is still blank. 
  Start 3-1-1-6.

3-1-1-6 - Replace the mini PC (see SOP here) and verify successful machine startup and touchscreen functionality.

• Result 1 - The touchscreen works fine. 
  Issue close.
  Root cause: The mini PC fails.
  
  
• Result 2 - The touchscreen is still blank. 
  Start 3-1-2-1.

3-1-2-1 - Confirm that the HDMI cable, power cable, and touch (USB) cable of the touchscreen are properly connected at both the screen end and the Mini PC (Raspberry Pi) end.

• Result 1 - All cables are correctly connected. 
  Start 3-1-2-3.
  
  
• Result 2 - The cable(s) is loose or disconnected. 
  Start 3-1-2-2.

3-1-2-2 - Reconnect the cables properly. Then, verify touchscreen functionality.

• Result 1 - The touchscreen works fine. 
  Issue close.
  Root cause: Cable(s) is disconnected.
  
  
• Result 2 - The touchscreen is still blank. 
  Start 3-1-2-3.

3-1-2-3 - Remove the touchscreen from the neck (leave the cables connecting with the touchscreen), and verify touchscreen functionality.

• Result 1 - The touchscreen works fine. 
  Replace the excessively long screws and, upon reassembly, ensure the screen functions correctly. Issue close. 
  Root cause: Short circuit caused by contact between the screws and the screen bracket.
  
  
• Result 2 - The touchscreen is still blank. 
  Start 3-1-2-4.

3-1-2-4 - Connect the cables to a new touchscreen and verify touchscreen functionality.

• Result 1 - The touchscreen works fine. 
  Issue close.
  Root cause: The touchscreen fails.
  
  
• Result 2 - The touchscreen is still blank. 
  Start 3-1-3-1.

3-1-3-1 - Measure the voltage at the "b37_J12V1(Power)" connector on the control board. The expected reading should be 12V.

• Result 1 - The reading is 12V. 
  Start 3-1-3-3.
  
  
• Result 2 - The reading is not 12V. 
  Start 3-1-3-2. (If you've done the control board replacement in the previous step, escalate to FAE directly)

3-1-3-2 - Replace the control board (see SOP here) and verify touchscreen functionality.

• Result 1 - The touchscreen works fine. 
  Issue close.
  Root cause: "b37_J12V1(Power)" connector on the control board fails.
  
  
• Result 2 - The touchscreen is still blank. 
  Start 3-1-3-3.

3-1-3-3 - Replace the original HDMI cable with a new/functional one, and verify touchscreen functionality.

• Result 1 - The touchscreen works fine. 
  Issue close.
  Root cause: The HDMI cable fails.
  
  
• Result 2 - The touchscreen is still blank. 
  Escalate to FAE.