danknasty
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Testing voltage on the pi B+

Mon Aug 18, 2014 11:33 pm

How do you test the voltage on the pi b+ since it does not have the test points tp1 and tp2.

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mahjongg
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Re: Testing voltage on the pi B+

Mon Aug 18, 2014 11:45 pm

It has test pads (not holes) on the bottom, marked PP3 (GND) and PP7 (VCC).

seen here in the bottom right hand corner (open picture in new windows to enlarge somewhat):
Image

P.S. PP1 is VCC before it goes to the polyfuse!
So powering the PI by soldering wires to PP3 (GND) and PP1 (+5V) is functionally the same as powering the PI through the microUSB, but its possible it will invalidate the guarantee if you solder directly to the board. Also the PI isn't protected this way against reversing VCC and GND, and reversing them, (putting -5V into the PI) will immediately destroy your PI!

Surjit
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Re: Testing voltage on the pi B+

Thu Aug 02, 2018 7:52 am

Hi mahjongg,

I have a power supply connected to PP3 (GND) and PP7 (VCC), which Drops to 4.6 V for 4nS and come back to 4.75V. I have some time SD Card corruption issue. Could this be an issue?

According to,

https://www.raspberrypi.org/documentati ... d-cards.md

GPIO VCC must be above 4.75V and in One of your post,

viewtopic.php?t=45819

You have said the SD Card will still work till 4V because of internal 3.3V Regulator.

Please let me know whats your view on this.

Many thanks.
Regards,
Surjit

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RaTTuS
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Re: Testing voltage on the pi B+

Thu Aug 02, 2018 8:32 am

make a better PSU that does not drop , or fatter cables
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jamesh
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Re: Testing voltage on the pi B+

Thu Aug 02, 2018 12:29 pm

Thread necro, closing.
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