I had the same problem with a 3B. Does the red power LED come on? If not, the fault is a low voltage detector chip running off the USB power socket +ve power connection.. The output during normal voltage should be a '1' indicating a voltage above the trigger point and this turns on a transistor that lights the red led.
The chip can fail with a '0' output which holds the LED off and causes the OS to report low voltage. The Raspi, otherwise works as normal.
Search out the simplified circuit schematic for your Pi and look for the transistor driving the red LED. The three pin SMD chip driving this transistor is the component in question. You will find the component number on the diagram and find it a few mm away from the red LED on the board.
The markings on the diagram are what you need to source replacements. The markings on the SMD component are misleading. I managed to get some at a low price from China.
If you have dealt with SMD components, you will find it fairly easy to replace because there is space around it. The only problem I found is that the adhesive holding the SMD to the board prior to soldering was difficult to release.
The chip can fail with a '0' output which holds the LED off and causes the OS to report low voltage. The Raspi, otherwise works as normal.
Search out the simplified circuit schematic for your Pi and look for the transistor driving the red LED. The three pin SMD chip driving this transistor is the component in question. You will find the component number on the diagram and find it a few mm away from the red LED on the board.
The markings on the diagram are what you need to source replacements. The markings on the SMD component are misleading. I managed to get some at a low price from China.
If you have dealt with SMD components, you will find it fairly easy to replace because there is space around it. The only problem I found is that the adhesive holding the SMD to the board prior to soldering was difficult to release.
Statistics: Posted by royleith — Fri Apr 05, 2024 8:50 pm