Rock64 Power Supply Polarity
#1
Hi Folks,

Have just got a Rock64, not with the power supply though, so have picked a suitable one up from my
local electronics store. Does anyone know what the power supply pin polarity should be ?

Tip positive or tip negative ? Would rather not blow the board up ;-) I did look at schematics but electronics was
never my strong suit :-)

Thanks again !
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#2
(09-22-2017, 01:31 PM)marillionkb5 Wrote: Have just got a Rock64, not with the power supply though, so have picked a suitable one up from my
local electronics store. Does anyone know what the power supply pin polarity should be ?


hi,  the polarity of the Rock64 power supply is  +5v center,   ground sleeve.
marcushh777    Cool

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#3
Lovely, thank you very much !
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#4
(09-22-2017, 02:12 PM)MarkHaysHarris777 Wrote:
(09-22-2017, 01:31 PM)marillionkb5 Wrote: Have just got a Rock64, not with the power supply though, so have picked a suitable one up from my
local electronics store. Does anyone know what the power supply pin polarity should be ?


hi,  the polarity of the Rock64 power supply is  +5v center,   ground sleeve.

So there are three pins on the barrel jack connecting it to the board. The center of the barrel jack is the rightmost pin if looking into the jack. The center pin contacts the sleeve of the barrel jack, so does that mean this pin is the ground pin? In that case, where is the -5V pin?
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#5
those plugs are always grounded twice.
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#6
(12-16-2017, 04:52 PM)Lamensis Wrote: those plugs are always grounded twice.

Oh ok. So if I was desoldering the barrel jack and connecting it straight to a power supply, I would use one ground pin for the -5V and one for the actual ground?
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#7
No. What is your goal? you can not make a 3 pin device out of a 2 pin. see this:
[Image: niedervolt-steckverbinder-buchse-einbau-...=520&y=520]
the double ground connection of the plug is internal.
so you can either use +5V and GND or change the polarity to -5V and GND, but keep in mind that the second solution will fry your board.
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#8
There are no -5V anywhere on the board... why does this keep coming up? DC input is a positive 5V potential difference vs GND....
Come have a chat in the Pine A64 IRC channel >>
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#9
(12-18-2017, 08:30 AM)xalius Wrote: There are no -5V anywhere on the board... why does this keep coming up? DC input is a positive 5V potential difference vs GND....
good question. several new members raising the issue of -5v.  so maybe because some other boards they know about and think those boards have -5v they come to the rock64 forum knowing very little about the board and start making assumptions? i've noticed just about the same thing with the issue of supplying 5v to gpio, that has been raise in several threads by i guess folks from rpi and others reading that it is done. of course it is done by many but that does not mean it is good thing to do. rock64 has some voltage and surge protection on the proper 5V in connector line and does not have that on the 5v gpio lines. as well as any diodes on the proper 5v line will of course mess with 5v from gpio. i'm sorry for being crass by mentioning this but it is entirely possible for nutrition and energy to be supplied to the human body by putting a feeding tube in the anus. but usually folks just eat and take supplements via oral, the mouth. so, apply 5v energy via designed inputs and not designed outputs.
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#10
(12-18-2017, 09:33 AM)dkryder Wrote:
(12-18-2017, 08:30 AM)xalius Wrote: There are no -5V anywhere on the board... why does this keep coming up? DC input is a positive 5V potential difference vs GND....
good question. several new members raising the issue of -5v.  so maybe because some other boards they know about and think those boards have -5v they come to the rock64 forum knowing very little about the board and start making assumptions? i've noticed just about the same thing with the issue of supplying 5v to gpio, that has been raise in several threads by i guess folks from rpi and others reading that it is done. of course it is done by many but that does not mean it is good thing to do. rock64 has some voltage and surge protection on the proper 5V in connector line and does not have that on the 5v gpio lines. as well as any diodes on the proper 5v line will of course mess with 5v from gpio.  i'm sorry for being crass by mentioning this but it is entirely possible for nutrition and energy to be supplied to the human body by putting a feeding tube in the anus. but usually folks just eat and take supplements via oral, the mouth. so, apply 5v energy via designed inputs and not designed outputs.

The -5V is neutral. Most adapters have a +5V, -5V (neutral), and ground. Personally, I do not like to refer to the neutral as -5V, though that is how it is refferred to in other posts on this forum. The barrel jack on the board has 3 pins connecting it to the board. Is the third pin for structural integrity then?

(12-18-2017, 10:57 AM)nmhart322 Wrote:
(12-18-2017, 09:33 AM)dkryder Wrote:
(12-18-2017, 08:30 AM)xalius Wrote: There are no -5V anywhere on the board... why does this keep coming up? DC input is a positive 5V potential difference vs GND....
good question. several new members raising the issue of -5v.  so maybe because some other boards they know about and think those boards have -5v they come to the rock64 forum knowing very little about the board and start making assumptions? i've noticed just about the same thing with the issue of supplying 5v to gpio, that has been raise in several threads by i guess folks from rpi and others reading that it is done. of course it is done by many but that does not mean it is good thing to do. rock64 has some voltage and surge protection on the proper 5V in connector line and does not have that on the 5v gpio lines. as well as any diodes on the proper 5v line will of course mess with 5v from gpio.  i'm sorry for being crass by mentioning this but it is entirely possible for nutrition and energy to be supplied to the human body by putting a feeding tube in the anus. but usually folks just eat and take supplements via oral, the mouth. so, apply 5v energy via designed inputs and not designed outputs.

The -5V is neutral. Most adapters have a +5V, -5V (neutral), and ground. Personally, I do not like to refer to the neutral as -5V, though that is how it is refferred to in other posts on this forum. The barrel jack on the board has 3 pins connecting it to the board. Is the third pin for structural integrity then?

I actually just answered my own question. The 5V barrel wall adapter for the rock64 (or pretty much any barrel adapter) has only 2 wires, thus it is +5V and either neutral or ground, whatever you want to call it. Usually when you hook up electronics to +5V and ground (with larger electronics), it causes a short in the breaker. But I guess with this board, the returning voltage is so minimal that it doesn't matter

Here is a website that explains all this positive, negative, and ground scenario
https://electronics.stackexchange.com/qu...l-and-grou
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