The only official power supply is 2A https://www.raspberrypi.org/products/un ... er-supply/Redsandro wrote:I have the official one, and it "sucks". It barely takes one amp. It says it can provide one amp, but I've never measured anything above 800mA.
The problem seems to be more technical: Both inputs seem to be limited on the Pi. What hardware component do I need to solder off and bridge in order for this limitation to be gone?
Hold the warnings. A high quality power source (which the official Pi one is not) outputs a steady level of power.
It's a long time ago. I think I purchased this in 2012. It was from a company called Farnell Element 14.klricks wrote:Which RPi model do you have and what was attached to the RPi when you got the 800mA measurement?
I mentioned 1b (or b1) in the TS, but I honestly don't know anything beyond that. Here's the cpuinfo:RaTTuS wrote:what model of Rpi?
Code: Select all
processor : 0 model name : ARMv6-compatible processor rev 7 (v6l) BogoMIPS : 2.00 Features : half thumb fastmult vfp edsp java tls CPU implementer : 0x41 CPU architecture: 7 CPU variant : 0x0 CPU part : 0xb76 CPU revision : 7 Hardware : BCM2708 Revision : 000d
Forgot to measure. I was only interested in amps because none of my power supplies could satisfy the Pi from single power source alone, even though they can output 2.1 amps. So I know that the Pi limits this, and was curious to see. I think this Pi is "old" and needs to be "fixed".what is the voltage as measured on the test points ?
Thank you, this is very valuable information.klricks wrote:On the RPi B Rev 1 there are polyfuses on the USB ports F1 and F2 near the USB ports. These were removed in later versions. I think they are rated at 180mA and would not allow higher power devices such a WIFI to work. They also block 'backfeeding' from the USB ports. You can remove F1 and F2 and short the pads with a wire or just leave them in and solder a wire jumper across them. This will make a B Rev 1 like the B Rev 2.
The main fuse F3 is rated at 750mA. The RPi will be unstable if you attempt to draw more than that. Your RPi will probably work after fixing F1 and F2. If not, you can decide what to do with F3, or you can power from the GPIO pins which bypasses F3.
I cannot reproduce this right now because I don't have the right cables to backfeed from USB alone so the Pi plus the dongle are fed through this one power supply. But I'm using a Charger Doctor:Burngate wrote:You seem pretty sure your Pi is taking 800mA; how are you measuring this? Putting anything in series with the power supply is going to reduce the 5v
suggest that is is a later version with 0 ohm resistersRedsandro wrote:..
Hardware : BCM2708
Revision : 000d[/code]...
You hero! That works? I had never thought of that. I was cutting precious USB cables to connect to other power (like PC PSU).rpdom wrote:you could power via a 5V and GND pin on the GPIO. That will bypass the input fuse (but you'll have no protection).
I suddenly started using the Pi's that I have for 2 - 3 years now, so I am pretty new with it. What are considered "the" test points?RaTTuS wrote:measure the voltage on the test points
http://elinux.org/R-Pi_Troubleshooting# ... r_problemsRedsandro wrote:RaTTuS wrote:measure the voltage on the test points
It's much easier to see if you can boot an operating system.Redsandro wrote:Is there a way to see what version Pi something is just looking at the board?
Code: Select all
[email protected] ~ $ cat /sys/firmware/devicetree/base/model;echo Raspberry Pi 2 Model B Rev 1.1
I'm fairly certain that you're incorrect w.r.t. "The dongle adds about 300 mA". This is based upon extensive tests I performed upon three such devices when they first became available:Redsandro wrote: ...
But I'm using a Charger Doctor:
The dongle adds about 300 mA.