As far as I know, you can not disable only one USB. When you turn USBs power off, also the Ethernet port turned off. I don't know if there is a way to disable USB/Ethernet in config.txt, but in cmd line you can do it with:
echo '1-1' |sudo tee /sys/bus/usb/drivers/usb/unbind
To enable the ports use:
echo '1-1' | sudo tee /sys/bus/usb/drivers/usb/bind
This is an exercise in futility!
Disabling devices will make very little difference in power usage, which is mainly determined by processor load.
About the ONLY device which will have any affect is WiFi.
You should consider a Pi3A+ which has lower consumption and no USB hub or Ethernet.
Supplying 5.5V to a Pi should not cause damage, although it is inadvisable. See https://raspberrypi.stackexchange.com/a/99653/8697
Test the voltage on Pin 1 (3.3V) - if this is absent the Pi is dead. NOTE be careful to avoid accidentally shorting 3.3V to any other pin - this is invariably fatal!
PS Measuring anything on a Pi with a multimeter on the ...
I have used a micro USB to USB C adapter to power my Pi4B. I used a 2 amp 5V wall-wart to provide the power. Please be aware that I only use my Pi's headless so my current requirements may be less than yours.
I am currently powering the Pi4B via the 5V and ground pins on the expansion header (using a 5V UBEC powered from a 12V laptop PSU).
For connecting two USB SSD/HDDs, does an Rpi USB Hub need any external power?
I measured the idle current and write current of a 1TB SSD, and a2TB HDD.
SSD's idle current is 0mA, and write current around 180mA
HDD's idle (spinning) current is 170mA, and write current 200mA ~
My conclusion is that for hobbyist's ...
The Pi3B+ can supply up to 1.2A total across the 4 USB ports. See Raspberry Pi Power Limitations.
This assumes the Pi power supply is adequate.
Whether this would be adequate for 2 SSD drives, depends on the drives.
My experience is that the voltage from the USB ports often falls below that required for power hungry external drives, so a powered hub is ...
So you doesn't have power on the 3.3V.
You may have made a shortcut, and fried the 3.3 power supply regulator. One way of trying to be sure of that (and verify the CPU), would be to power the board with an external 3.3V power supply (of good quality)
So remove all the wire who may have started the problem, and try to boot the board this way…
If the power ...
Even with 50 years experience as an Electrical Engineer I wouldn't poke at a 0.1" header with a multimeter probe (although the 50 years experience probably taught me the hard way).
Attach Du-pont leads to the pins, and measure the flying leads.
Test the voltage on Pin 1 (3.3V) - if this is absent the Pi is dead.
Connecting Pin 39 and 40 will not cause any ...
The Pi has 3 "components" the CPU, GPIO and Video Core which are relatively independent.
Even when the Pi is shutdown the Video Core continues to run, and the GPIO pins retail their state; only the CPU is not running.
The 3.3V is supplied by separate circuitry and will be present while ever the Pi is connected to a 5V supply.
The best way to reliably ...
This howchoo post shows how to connect an LED to show the status of the Pi. The LED is steady on when the Pi is running, and off after shutdown.
Add this line to /boot/config.txt, and reboot
Connect the TxD pin (GPIO pin 8) to the positive lead of a 2 or 3 volt LED.
Connect a ground pin (e.g. GPIO pin 6) to a 330 ohm resistor, ...
I don't see that connecting pin 40 (GPIO21, aux SPI SCLK) to ground would have any bad effect.
Most GPIO are set as inputs. Connecting an input mode GPIO to ground or 3V3 is normal operation and has no bad effect.
If the GPIO was set in output mode and set high then it might damage the GPIO if connected to ground for an extended period. I don't think a ...
The best option is a good quality power supply, as cheap brands may say they are rated at 2.4 amps, when they don't actually supply that much. Based on the numerous bad experiences i've had with 3rd party chargers, i'd highly recommend buying the official one from the foundation!
Whether that is adequate for the hard drive is another question. I haven't ...
How can we tell apart 3rd party chargers that would work with RPi4?
You can either rely on reviews or ask the seller and take their word for it, or you can get the supply, test it, and return it back if it doesn't perform. Obviously, in the latter case you'll want to buy it from a place where you can return it for free.
There is no way to tell from the ...
Use a PoE Hat:
Third-party USB-C charging devices can be cheaply wired, potentially destroying connected devices as well as starting fires. A safer alternative is to power your Pi using PoE which beyond reducing these risks, offer additional benefits:
Using a PoE Hat is easy to setup and enables you to:
Emplace a Pi at a much greater distance ...
The spec specifically states that:
A good quality 2.5A power supply can be used if downstream USB peripherals consume less than 500mA in total.
Using a 2.4A power supply with the Pi 4 and a 2.5" HDD is going to be borderline assuming a typical power rating of the 2.5" drive of about 1.8W to 2.7W (see here). From the above statement - after all it really ...
The power management IC (PMIC, see section 3) is a MXL7704 with an input voltage range of 4.0 V to 5.5 V and an absolute maximum rating of 6 V that must not be exceeded.
Considering that the downstream USB ports are directly connected to the 5 V power rail the 5 V supply should also comply with USB electrical specifications: 4.45 V to 5.25 V ...
I've successfully run the official POE Hat and the official touchscreen. It would only work if I ran the screen off the GPIO 5v/Ground GPIO pins to the screen, which required a GPIO pin extender module (so the pins push through the POE HAT). I've seen notes online that some people have soldered the 5v/ground pins from the bottom of the Pi to make for a ...
Let's take a peek at the Pi 3B schematic. I'll assume you'll use the micro USB input.
Maximum reverse input voltage: 5V
Anything past -5V would probably result in catastrophic failure of the BCM857BS (V_EB absolute maximum rating violation on pins 2 and 1, but then, there are resistors.)
Absolute maximum input voltage without peripherals: 6V (but I wouldn'...
As many have already mentioned, do NOT use higher voltage. It'll fry your device. Rather try a charger/power supply that can power up to 3amps of current at 5V. You may have a hard time finding those, and even if you find, you'd see that most Chinese adapters are wrongly advertised, hence will not actually provide 3 amps. So unless you have a fast charger (...
If you want an actual button pusher for educational/entertainment needs, then you can ignore this answer.
Given your description, I would assume that this physical button is a normally open push button (NOPB) with two wires going to it. In this case, I would think you could come up with a simpler solution that involves tapping one or both of those wires. ...
The problem of building a proper power supply for the Raspberry has been discussed at lots of places, and the canonical answer is to buy the official Raspberry power adapter.
I just bought one myself, price was not too high, something like 14 euro, and this includes a contribution to some charitable projects. It is rated 5.1 V and 2 A, and has pretty thick ...
While the other Anwsers are correct as in 'you should not provide any higher voltage then 5.25V', the solution to your initial problem (yellow thunderbolt sign) is to use a power supply which provides a higher current. the official raspberry pi power supply is labeled at 2.5A
And in my experience (running a >100 RasPi research network) a 2A power supply is ...