CPU3:not online

[flipjay]

Unsure why but my rpi3 locked up yesterday when using remote VNC client. The pi shut down by itself.

Reverted to a plugin monitor and mouse/keyboard option. Attempts to power now shows CPU3: issue but boot process continues normally. When the PI home screen displays there is no keyboard or mouse available. After approx 20 seconds a small red square appears in the upper right corner of the screen. I have no control of the system, so am unable to attempt repair.

Does this mean thhat CPU3: has been damaged? If I am forced to replace the mother board and I use the current chip will I retain my files?

[mfa298]

Unsure why but my rpi3 locked up yesterday when using remote VNC client. The pi shut down by itself.

Reverted to a plugin monitor and mouse/keyboard option. Attempts to power now shows CPU3: issue but boot process continues normally. When the PI home screen displays there is no keyboard or mouse available. After approx 20 seconds a small red square appears in the upper right corner of the screen. I have no control of the system, so am unable to attempt repair.

Does this mean thhat CPU3: has been damaged? If I am forced to replace the mother board and I use the current chip will I retain my files?

The red square indicates the Pi is overheating. If there's anything plugged into the GPIO header then it might be worth removing it. You may also want to check what's running on the Pi.

If the worst has happened and the SoC is damaged then you could probably move the SD card to a new Pi and have it just work. There's always a possibility however that the issue is with the SD card rather than the pi itself (there have been a few cases of SD cards getting very hot and burning)

[flipjay]

Thanks for quick reply. Good to know meaning of small red square.
I have unplugged everything from GPIO bus, also mouse and keyboard. The system still shows cpu3 not on line as the first item in booting. Proceeds as normal through entire boot sequence, displays home screen. With in 1 minute a yellow box appears at top right of screen and within 30 seconds it turns to red. Sure enough the SoC heat sink is hot to the touch

My conclusion - order new RPI board. Sure hope SD card transfer works!

Question 2. I understood the SOC would automatically shut down on overheat instead of burn out?

[wh7qq]

Question 2. I understood the SOC would automatically shut down on overheat instead of burn out?

Automatic protection is sorta like a parachute...if you are falling out of an airplane, you hope and pray that the @#!$## thing works but they do fail from time to time.

[drgeoff]

The GPIOs are relatively easily damaged by electrical abuse. The damage usually spreads within the chip often leading to complete failure. The overheating and missing CPU3 may be signs that your RPi3 is on that path.

Before replacing it you should attempt to ascertain why this one has failed. You risk the same fate befalling its successor.

[flipjay]

Thanks for the warning. I am using the pins as follows:
4 ports out to a JBtek 4 Channel DC 5V Relay Module - never more than two active
2 (sda and slc) to BH1750FVI Digital Light Intensity Sensor Module:
1 port to input (12 volt 50,000 ohm potentiometer tap at 3.5 volts)
I have tied a rpi ground pin to ground of this independent 12 volt source

Also using Raspberry Pi Camera
Running headless using VNC server over local network

And the suspected culprit:
powering (using 5 volt bus pin) a small LED flashlight.
on continuously (for camera image quality)
At rated 4.5 volts the measured draw is 170 milliamps.

I will move this to an independent power source before I burn up another RPI with my stumbling around.
Any other obvious problems?

[RaTTuS]

show your wiring...
I suspect you have put more than 3.3v onto the GPIO or tried to pull ore than 16mA