1

Usual problem - USB power has gone.

Where is the fuse located on the board? The reduced schematics on the RPi webpage does not show the USB at all.

  • Why do you want to know? – Milliways Sep 20 '18 at 9:46
  • I want replace it with something having a better rating – P__J__ Sep 20 '18 at 9:49
  • If you can't find the fuse (which is clearly visible and labelled in the bottom right hand corner near the power connector) it is doubtful you could replace it - even if you could find a replacement - which would be a poor idea anyway as it is doubtful if the board traces could carry more than 2.5A. NOTE the fuse is clearly labelled on the schematic. – Milliways Sep 20 '18 at 9:58
  • I am not asking about the F1 fuse, Only the one protecting the USB! – P__J__ Sep 20 '18 at 10:05
  • There isn't one! USB Current is supplied through a Current-Limited Power Switch (AP2553?) – Milliways Sep 20 '18 at 10:05
1

As there is no information about it on the RPi website and something definitely has blown up on the board cutting the USB 5V supply, I have decided to measure where the the "raw" USB input is and hardwire it on the board.

Here is my workaround (the wire should be shorter):

enter image description here enter image description here

PP2/PP3 <-----> PP27

  • Don't you risk "starving" the RPi? – Gerard H. Pille Sep 20 '18 at 11:54
  • @GerardH.Pille I do, but the another choice is to bin the RPi. But the proper power + 330u cap will probably sort that problem out. Actually I have connected my USB device (it sources about 300mA) - the RPi is quite heavily loaded ~90-95% but the power looks OK (it is connected to the scope now) – P__J__ Sep 20 '18 at 11:58
  • You do have the problem even if the RPi is not "loaded" ? – Gerard H. Pille Sep 20 '18 at 12:01
  • The problem is that USB power is dead. And this test was only to check if I will not starve my RPi – P__J__ Sep 20 '18 at 12:06
0

On this page there is a nice picture.

https://www.petervis.com/Raspberry_PI/Raspberry_Pi_Dead/Raspberry_Pi_Fuse.html

  • but it is not the RPI 3 only the older version. I have found a lots of old RPi information but nothing about the RPI 3 B (not B+) – P__J__ Sep 20 '18 at 9:40
  • Sorry. Do you mean the 3B does not have the fuse as the 3B+ has? – Gerard H. Pille Sep 20 '18 at 9:55
  • And the yellow 3592 so close to the usb power port? raspberrypi.org/app/uploads/2017/05/… – Gerard H. Pille Sep 20 '18 at 10:00
  • I try t find that one which cuts the USB power. – P__J__ Sep 20 '18 at 11:59
  • That may not be a fuse at all. Perhaps the Pi can manage how much power may go to the USB connectors. – Gerard H. Pille Sep 20 '18 at 17:32

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