Raspberry Pi runs fine, but there is no picture when using HDMI Repair

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Raspberry Pi runs fine, but there is no picture when using HDMI Repair
Device Raspberry Pi
Affects part(s)
Needs equipment
Difficulty
Type


Problem description

Raspberry Pi runs fine, but there is no picture when using the HDMI port.

Pi 3B HDMI Circuit
Pi 3B HDMI Circuit

Symptoms

  • No picture when using the HDMI port.

Solution

  • Test the internal flyback diodes of transistors Q2 and Q5 with a multimeter. The voltage drop should be in the range of 500 to 700mV. If there is a short (0V), the respective transistor needs to be replaced. Its part number is DMG1012T.
  • Use the diode testing mode of a multimeter and connect the black lead to GND (e.g. the metal part of the micro-USB socket). Use the red lead to probe the contacts on top of L4 to L7 (highlighted pink in the image). There should be no reading. If any value is shown while touching any of the four coils (e.g. 1100mV), the HDMI circuitry inside the CPU is probably broken. This fault cannot be repaired.
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