Rocker86
Posts: 7
Joined: Tue Jun 23, 2020 7:16 am

Raspi 4 power issue

Tue Jun 23, 2020 7:29 am

Dear all,

I am having troubles with powering my brand new Raspberry Pi 4.

If I insert more that 2 usb devices and power it up, that it won't boot and a red led will start blinking.

The funny thing is that these 3 usb devices that I want to use with the raspberry doesn't require to be powered by him, as they are satellite tuners with their own power supplies. Note I am using the original Raspberry power supply usb-c

But this is the most strange behavior: If I unplug all usb devices, power up the raspberry seeing the green light blinking and right after insert all 3 usb devices, then everything is working fine -> raspberry will boot correctly and will recognize all usb devices allowing me to use them.

Initially I thought about a hardware problem of my Raspi4. So, I tried with another Raspi4 with another original power supply and had the same problem. Lastly, I tried to do the same with my old Raspi3 (not 3B+) and it worked immediately without any issue.

So, I assume it is a raspberry pi 4 specific problem.

Is it possible to solve the problem by changing some settings, maybe?

jamesh
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
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Re: Raspi 4 power issue

Tue Jun 23, 2020 8:43 am

What are the devices you are using? Are they all the same, is there a specific one that stops the boot, or does it have to be all three? Do you also have keyboard/mouse plugged in to the USB?
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pfletch101
Posts: 630
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Re: Raspi 4 power issue

Tue Jun 23, 2020 2:44 pm

Rocker86 wrote:
Tue Jun 23, 2020 7:29 am
Dear all,

I am having troubles with powering my brand new Raspberry Pi 4.

If I insert more that 2 usb devices and power it up, that it won't boot and a red led will start blinking.

The funny thing is that these 3 usb devices that I want to use with the raspberry doesn't require to be powered by him, as they are satellite tuners with their own power supplies. Note I am using the original Raspberry power supply usb-c

But this is the most strange behavior: If I unplug all usb devices, power up the raspberry seeing the green light blinking and right after insert all 3 usb devices, then everything is working fine -> raspberry will boot correctly and will recognize all usb devices allowing me to use them.

Initially I thought about a hardware problem of my Raspi4. So, I tried with another Raspi4 with another original power supply and had the same problem. Lastly, I tried to do the same with my old Raspi3 (not 3B+) and it worked immediately without any issue.

So, I assume it is a raspberry pi 4 specific problem.

Is it possible to solve the problem by changing some settings, maybe?
My interpretation of this would be that the USB devices are transiently drawing a lot of power (relatively speaking) at boot. Even devices with their own power supplies may draw some power from the USB socket into which they are plugged. If all three are plugged in when the Pi is powered on, they all draw their startup power simultaneously, and bring down the power line, If they are plugged in (almost certainly one at a time) after the Pi boots, they boot one at a time, and the power drain is within the limits that the power supply can maintain.

Rocker86
Posts: 7
Joined: Tue Jun 23, 2020 7:16 am

Re: Raspi 4 power issue

Wed Jun 24, 2020 7:42 am

Thank you for yours prompt reply :)

@jamesh

I am using the raspberry as a headless network tv server so I don't have mouse, keyboard and monitor connected to it. I plug into the usb ports 2 satellite tuners and a smartcard reader. Both tuners have their own power supplies, when the smart card reader is powered by the usb plug of the Raspberry.

Scenario 1: I unplug the smartcard reader and plug in the 2 tuners: raspi won't boot
Scenario 2: I plug the smartcard reader and only 1 tuner: raspi will boot. After the boot process I can plug the second tuner without a problem and will be recognized by the system.

Probably you will say: ok, so remeber to unplug one tuner if you have to reboot and then plug in it back after the boot process. It's ok...but I prefer a reliable system that will boot correctly and autonomously in every scenario. Surpsingly, the Pi3 will do it but I need more CPU power and gigabit ethernet so..

@pfletch101

Probably developers should tell raspi to retain the needed power for the cpu when system is booting and then pass it to the usb controller? I mean..if Raspi3 can boot with 3 usb devices plugged in, why Raspi 4 shoudn't ? Where could be the problem? (I hope it is not a hardware limitation). By the way, I am using the new Pi4 rev 1.2 board with official power supply

Rocker86
Posts: 7
Joined: Tue Jun 23, 2020 7:16 am

Re: Raspi 4 power issue

Fri Jun 26, 2020 11:28 am

bump

LTolledo
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Location: Anime Heartland

Re: Raspi 4 power issue

Fri Jun 26, 2020 11:46 am

you have not informed us the current requirement of the TV tuners....

Note: max current that can be supplied by the RPi USB ports combined (in any combination) is 1.2A or 1200mA, and its non-negotiable!
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Rocker86
Posts: 7
Joined: Tue Jun 23, 2020 7:16 am

Re: Raspi 4 power issue

Tue Jun 30, 2020 9:54 am

Tuners have their own power supply, so no power is required from Raspberry. Raspy 3 is working, while raspi4 is not, so there is a problem in usb ports of raspi4 for sure

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